Grow Lights

Grow Lights

Grow lights have revolutionized how hobbyists and professional cultivators alike think about their options when it comes to growing plants.  It used to be the case that gardeners, farmers, and herbalists had to work within the fairly strict natural constraints of seasonal growing cycles, which greatly limited what kinds of plants could be grown in each location.  Today, though, it is not uncommon for growers to harvest their crops year-round.

Those who are just beginning to dip their toes in the water when it comes to indoor growing are often overwhelmed by the sheer number of options available to them when it comes to grow lights.  They don’t have to be, though.  Ultimately, each type of light has different pros and cons and is used in different circumstances, so all growers have to do to determine which of them will be the best fit is to consider all of the relevant details.

This article will offer a brief introduction to grow lights and how they are used, followed by a helpful breakdown of the different kinds of lights available and the pros and cons of each of them.  It will then offer some insight into energy savings credits and offer some best-practice advice for those who are new to indoor growers.  This information will allow even novice growers to begin their next season with the confidence that they have chosen the perfect light fixtures for their unique applications, so let’s dive in.

The Basics

What all grow lights have in common is that they are designed to stimulate plant growth indoors by providing the light required to facilitate photosynthesis.  They can be used year-round, or they can be placed in greenhouses to supplement the natural sunlight still available to plants by ensuring that they receive enough light to grow.  Without that extra light, plants grown in the winter would be impractically long and spindly even if they were being grown in full daylight.

The primary difference between different types of grow lights is the kind of light that they provide.  Some mimic the sun as accurately as possible, providing a light spectrum, color, temperature, and spectral outputs that is nearly identical to natural light.  Others are designed to mimic certain conditions under which plants will be better able to germinate or flower, providing more specific ranges of light spectrum, color, temperature, and lumen output.

There is no universal advantage to either sticking with one type of light that can be altered to provide different light value or changing the light source throughout the season.  Growers will need to have some idea of what kinds of plants they intend to cultivate prior to looking into grow lights, to begin with. 

Not sure exactly what kind of plants will be grown and just trying to get an idea of whether indoor grow lights will really provide a practical solution?  Those who are looking for more general information about grow lights and their many advantages can skip to the later sections of this guide.  For now, though, let’s take a look at the different categories of available lights.

High-Intensity Discharge (HID) Lights

HID grow lights feature large bulb systems designed to produce light through an ignition process.  There are three kinds of HID lights used for growing plants.  These are known as high-pressure sodium (HPS) lights, metal halide (MH) lights, and hybrid lights that use a combination of these technologies.

This category of grow lights has been growing substantially in recent years thanks to the high lumen-per-watt efficiency of HIDs.  Different types of HIDs produce different spectra of light, but all of them work on the same general principals.  They work by creating an electrical arc between two tungsten electrodes, causing the gas inside of the bulb to be ignited.

The general advantages of HID lights are that they provide high light intensity, are adjustable, and offer the highest yield per watt out of any category of conventional grow light.  That doesn’t make them perfect, though. Not all growers find their high yield constitutes enough of an advantage to overcome the several disadvantages associated with this class of lighting.

One of the largest disadvantages is that there is always a possibility of burning plants due to the fact that HID bulbs produce more heat than many of their alternatives.  They also require a good deal of additional equipment, including ballasts and reflectors, and the bulbs must be replaced over time.

Double-Ended (DE) Lights

DE grow lights are slightly different from the HID lights described above.  They still require ballasts, but instead of connecting to just one ballast port they actually connect to both ends.  This helps to explain their name.

Lights that form a single connection point to a ballast tend to become less efficient over time, while DE lights maintain 90% efficiency even after 10,000 hours of use.  It is important to note, however, that their general efficiency is reduced by nitrogen contact.

The best-known type of DE light is the high-pressure sodium (HPS) lighting system, although HPS lights can also be single-ended.  The double-ended kinds of HPS lights are often used in hydroponics, although they can certainly be put to good use in other indoor growing scenarios, as well.

The primary advantages of grow lights are their longevity, as noted above, and their slim design.  This feature allows them to provide more light than their single-ended counterparts and helps to spread the light more evenly across the plants.  The fact that DE lights don’t have metal, as do their single-ended counterparts, also means that all of the light produced is able to be transferred unhindered to the plants.

The primary disadvantages of DE lights are the efficiency reduction noted above and the fact that like HID lights, they can wind up burning plants.  DE lights can also be more expensive than their single-ended alternatives, especially when growers purchase the newest and most advanced models.

Fluorescent Lights

Quite popular among modern growers, fluorescent lights are cooler than both HID and DE lights.  This makes fluorescent grow lights perfect for propagating crops. 

Unfortunately, they’re less ideal for supporting plants in flowering or vegetative states, which means they can really only be used in conjunction with other types of grow lights.  The fact that they remain so popular despite this obvious disadvantage is a testament to how effective they truly are.

These lights are calibrated by diameter.  This helps to explain the “T” rating typically found after the name of a particular fluorescent bulb.  The “T” actually represents 1/8th of an inch, which means that a T5 fluorescent bulb will be 5/8ths of an inch in diameter.

As noted above, fluorescent lights are less than ideal for flowering and vegetative phases, which means they should really only be used for the specialized purpose of propagation.  The result of their inefficiency, when used in the later stages of growth, is that they also have the disadvantage of providing smaller yields per watt than other lights.  The ideal solution is, of course, to purchase fluorescent grow lights in addition to whatever lighting type growers choose for the remainder of their plants’ growth cycles.

The advantages of fluorescent lights are often considered to make them worth buying just for the propagation phase.  They’re long-lasting, energy efficient, able to cover a large surface area, and much more affordable than their alternatives.  Since fluorescent lights don’t produce as much heat, they may also be the only option for those growing in particularly short spaces.

LED Lights

LED lights are the comparative newcomers to the grow light game.  Many growers remain hesitant about purchasing these lights due to their higher initial cost, preferring to wait until their increased popularity makes LED lights more affordable.  Over time, though, even growers who purchase LED lights today will find that they will be provided with a solid return on their investments.

LED grow lights are energy-efficient and boast the lowest power costs of any grow light available on today’s markets.  They’re also long-lasting, which helps to make up for their higher cost over time, as well.  Other advantages of LED grow lights include their higher light production, the comparatively wide light spectrum that they provide, and their ease of use.

While many indoor growers find that LED lights are well worth the investment, not all of them find that the pros of LED lights outweigh their cons.  In addition to being more expensive due to their recent emergence on the market, they’re also less efficient than some of their alternatives for plants in their flowering phases.  On average, when they are used across a plant’s entire growth cycle, LED lights provide a slightly smaller yield per watt than their more conventional HPS alternatives, too.

Ceramic Metal Halide (CMH) Lights

CMH lights and their closest relatives the light emitting ceramics (LECs) are types of single-ended HID lights.  They’re both composed of ceramic elements and insulation and they’re both able to produce plenty of light to support even the vegetative and flowering stages of plants.  What most growers really like about CMH lights is that they are able to mimic natural sunlight very effectively in comparison to their alternatives, making them solid choices for all-purpose grow lights.  Single-ended CMH and LEC lights, which are so similar they’re actually interchangeable in most systems, also last longer than double-ended lights.

While these lights compare reasonably favorably to other lighting types, they’re not perfect.  They do require magnetic ballasts and they produce a good deal of heat, which often necessitates tall ceilings and accessories like fans.  They also expose plants to relatively high rates of UV light.

 

Federal Energy Savings Incentives

The Energy Independence and Security Act (EISA) passed by the United States Federal government in 2007, could be said to be at least partially responsible for the notable increase in the availability of high-efficiency lighting in recent years.  This Act required manufacturers to increase their products’ efficiency by at least 27 percent over the then-popular traditional incandescent bulbs.

Of course, this Act only benefits consumers indirectly and really, it only benefits those consumers who choose to buy fluorescent grow lights, LEDs, and other energy-efficient models.  The Department of Energy also developed the Better Buildings Outdoor Lighting Accelerator relatively early on in 2014 to incentivize public agencies and municipalities to install energy-efficient, high-performance lights.  Although this program stopped receiving funding in 2016, it did help the government assess barriers to increasing lighting efficiency among municipalities and continues to be used as a reference for the development of future plans.

The National Mortgage Association also provides a federally-funded incentive program.  This program, operated through the Fannie Mae Multifamily Green Financing Business, provides financial funding for energy efficiency improvements made on multifamily residential properties and cooperatives.  While these programs certainly constitute a step in the right direction, the direct-to-consumers incentive for purchasing more energy-efficient grow lights comes from individual states, not the Federal government.

State Energy Incentives

As of 2016, only 14 states were without some sort of energy efficiency incentive program that included lighting efficiency.  Even in these states, local governments may still provide grants, loans, or other forms of financial incentive to consumers on a city- or county-wide basis rather than a state-wide basis.  One example can be seen in the Property Accessed Clean Energy (PACE) program in the City of Winter Park, Florida.  This program offers consumers rebates when they upgrade their indoor lighting to use more energy-efficient technologies and provides funding to both residential and commercial business owners.

Of those 36 states that have enacted legislation that offers incentives for energy-efficient lighting or adopted incentives to accomplish the same goal, 12 have rebate programs that reimburse consumers directly, eight offer grants to local and state-level agencies and organizations, and five that offer sales tax exemptions for purchasing energy-efficient lighting.

State-Enacted Legislation

Six states enacted energy-efficient lighting legislation between the years 2013 and 2016.  Most of these Acts were drafted with town and county municipalities in mind.  Overall, though, the following states’ legislative efforts reflect a trend toward increasing state efforts to finance energy efficiency programs at all levels.

Alabama Senate Bill 220

In 2015, Alabama passed Senate Bill 220 to enable PACE financing.  This, in turn, has allowed many counties and municipalities throughout the state to finance improvements in energy efficiency.  Lighting projects are explicitly included as qualifying projects under Senate Bill 220.  The financing is issued through assessments on each property owner’s tax bill.

Arkansas Senate Bill 869

Arkansas also passed legislation in 2015 to support improvements in energy efficiency on a municipal level.  Senate Bill 869 authorizes the state to offer bonds for use financing energy efficiency projects, including lighting projects.

Kentucky House Bill 100

In 2015, the Kentucky state government passed House Bill 100 to enable PACE financing.  Like Alabama’s Senate Bill 220, Kentucky’s House Bill 100 allows counties and municipalities to take advantage of financing for energy efficiency improvement projects, including lighting.  Also like Alabama, Kentucky provides its financing through property tax bill assessments.

Maryland House Bill 786

Maryland passed its energy-efficiency project financing legislation in 2014.  House Bill 786 adds LED bulbs to the state’s existing list of energy efficient products that are exempt from taxes when purchased during President’s Day weekend.  Unfortunately, this Act expired automatically in 2017.

Nebraska Legislative Bill 1012

Legislative Bill 1012 was passed in Nebraska in 2016.  Like many of the other state-level legislative changes described above, it was designed to enable PACE financing for a wide array of energy-efficiency improvements, including lighting.

Rhode Island House Bill 5935 and Senate Bill 836

Rhode Island began to pass state-level legislation surrounding energy efficiency in 2013, making it one of the earlier adopters of energy improvement laws.  This piece of legislation created the Municipal Streetlight Investment Act, which, in turn, allows for the purchase of energy-efficient street lighting by municipalities at a reduced cost.  House Bill 5900, passed in 2015, extended the state’s existing public funding for renewable energy.

Rhode Island Executive Order 15-17

Rhode Island’s Executive Order 15-17 goes farther than the other legislative Acts described above when it comes to ensuring energy efficiency on a town and county level by establishing explicit energy efficiency goals for these state facilities.  According to this Executive Order, Rhode Island’s municipal facilities will have to be procuring 100% of their electricity from renewable resources by 2025.  Although it only applies to municipal organizations, Executive Order 15-17 does cover lighting efficiency projects.

Energy-Efficient Lighting Incentives

Many of those states that have not passed legislation regarding the financing of lighting efficiency projects still offer incentives to organizations and consumers to improve the efficiency of their lighting and these incentives are available to indoor growers.  27 of these programs implement low-interest or even zero-interest loans, while 12 enact consumer rebate programs, eight offer grants to local governments, and five offer tax exemptions for energy-efficient lighting. 

The NC Clean Energy Technology Center has compiled a comprehensive list of energy savings programs by state available through DSIRE USA.  Those who don’t want to spend hours searching through databases can also check out this state-by-state breakdown of the most relevant of these incentive programs below.

Fort Morgan, Colorado

The Municipal Energy Agency of Nebraska has partnered with Fort Morgan’s local municipal utility companies to offer cash incentives to commercial business owners interested in replacing their less efficient lights with more energy-efficient alternatives.  Energy-efficient grow lights are eligible under this program if they will be used for commercial farming or cultivation.  Eligible applicants will receive their cash incentives within four to six weeks after submitting their receipts.

State of Idaho

Rocky Mountain Power in Idaho offers rebates for energy-efficient lighting installations in addition to providing technical assistance for small businesses.  This program’s cash incentives can be applied to lighting retrofits, new construction, and renovation alike.

Illinois Rebate Programs

Ameren Illinois Utilities manages a rebate program for commercial, industrial, nonprofit, the federal government, and agricultural customers interested in upgrading to energy-efficient lighting.  The maximum cash incentive available through the program is $500,000 per project and it can be applied to any new construction, remodel, or retrofit.  Illinois indoor growers should know that any incentive request for more than $10,000 will need to be pre-approved by the utility company, though.

The state of Illinois offers a second rebate program managed by Commonwealth Edison Co and funded by the Illinois Energy Efficiency Portfolio Standard (EEPS) surcharge, as well.  Eligible technologies include LED lighting and other forms of energy-efficient lighting.  Only commercial, industrial, and federal government customers are eligible for this rebate, though. 

Minimum efficiency requirements for LEDs and other lights vary substantially under this rebate program.  The minimum incentive for eligible LED lighting is $5.00 per unit and the maximum is $20.00 per unit.  The minimum incentive for other forms of energy efficient lighting is $1.00 per lamp, while the maximum is $55.00 per lamp. 

Massachusetts Rebate Programs

The town of Reading in Massachusetts offers a rebate program that applies to lighting and lighting controls or sensors.  Rebates are available to a wide variety of organizations, including commercial and industrial businesses, local governments, nonprofits, and schools.  Most importantly, the rebate program is explicitly available to commercial indoor agricultural operations. 

The maximum incentive amount is either $25,000 per year or 50% of the purchase price of the eligible fixtures, which must achieve at least 25% energy savings.  The incentive for energy-efficient lighting, including grow lights, ranges from $10.00 per unit to $350.00 per unit, while the incentive for lighting controls and sensors ranges from $15.00 per unit to $60.00 per unit.

Rowley, Massachusetts also offers a rebate program for commercial businesses.  The program, funded by the Rowley Municipal Lighting Plant, offers cash rebates of up to $300 for commercial energy audits and provides funding for as much as 75% or up to $1,500 per audit of those measures recommended to improve efficiency, including energy-efficient lighting.

Minnesota Incentives

There are a variety of municipal utility companies in Minnesota that offer cash incentives to commercial customers who make the switch to eligible energy-efficient technologies, including lighting.  These cash incentives can be applied to both retrofitting projects and new construction.

Missouri Rebates

Columbia, Missouri offers rebates to commercial and industrial property owners who switch to more efficient lighting.  The maximum incentive is the lesser of either $22,500 or the cost of a 75 kW reduction.  Eligible customers must plan to achieve a 1-75 kW energy reduction when they switch to new lights and must undergo an audit prior to receiving their rebates.

Columbia is not the only city in Missouri that offers a rebate program.  The Southwest Electrical Cooperative also administrates an energy-efficient commercial lighting rebate program called the Take Control and Save Program.  An audit will still have to be performed prior to the issuance of any rebates.

Montana Rebates

The Flathead Electric Cooperative and Bonneville Power Administration offer a rebate program to commercial, industrial, and agricultural business owners who want to retrofit existing facilities with more energy-efficient lights or install energy-efficient lights in new buildings.  The administrator must approve rebates prior to the installation but the cost of those light fixtures that are deemed eligible, including energy-efficient grow lights, can be covered by as much as 70%.

North Carolina Rebate

The Randolph Electric Membership Corporation offers a rebate program for commercial and industrial property owners that make the switch to more energy-efficient lighting.  The rebate offers a set price of $0.30 per watt of energy saved by the new lights.  This can add up to a good deal of money for indoor farmers and cultivators in North Carolina.

New York Incentives

New York state has two incentive programs for small business owners.   One is funded by System Benefits Charge and administered by Rochester Gas and Electric Corporation.  Rochester area business owners whose electricity demands average less than 110 kW per month may be eligible to take part in this program, which will pay for up to 70% of the cost of lighting retrofits.

The second New York state incentive program also offers free energy assessments and covers up to 70% of the cost of lighting retrofits but it is available to small business owners across the state.  System Benefits Charge also funds this second program but it is administered by New York State Electric and Gas Corporation.  In both of these cases, small business owners who are interested in finding out their eligibility status will have to schedule a free energy assessment prior to moving forward with their retrofits.

Oregon Incentives

The Springfield Utility Board administers a cash incentive program available to commercial and industrial business owners, nonprofits, and government offices operating in the City of Springfield.   The amount of these incentives varies substantially, as does eligibility.  In order to be eligible, the expected savings from a retrofit or new construction must be at least 20% and the lighting equipment has to be on the administrator’s qualifying products list.

Tillamook County People’s Utility District also offers an incentive program for commercial, industrial, and agricultural customers who are switching to more efficient lighting.  The first step toward determining eligibility is to schedule a lighting analysis.  Only retrofits are eligible for this rebate program, not new construction.

A third entity, the Oregon Trail Electric Consumers Cooperative, offers a more inclusive retrofit company to Oregon commercial property owners.  The rebates can cover up to 70% of the cost of retrofitting existing lighting.

San Marcos, Texas

The City of San Marcos offers a rebate program that covers $250 per kW of energy reduction when commercial, industrial, institutional, or multifamily residential property owners switch to more energy-efficient lighting.  The maximum incentive for this program is $12,500.  Only lighting controls or sensors and the LED lighting are considered eligible technologies.

Vermont Rebates

Vermont offers two different rebate programs, one of which is available to commercial, industrial, institutional, and agricultural property owners, federal government offices, schools, and nonprofits and the other of which is only available to agricultural operations. 

The first of these rebate programs, offered by Efficiency Vermont, covers up to 100% of the purchase price of new lighting equipment that meets eligibility requirements.  Eligible lighting includes ENERGY STAR LED replacement lamps, fixtures, and retrofit kits as well as DLC replacement lamps.  The latter of these programs is also offered by Efficiency Vermont.  Agricultural operations can get rebates of between $25 and $75 for each new lighting fixture and between $20 and $150 for each new LED lighting fixture.

Washington State

There are several rebate programs for Washington state commercial indoor growers who want to upgrade their lights depending on what areas they live in.  The City of Richland offers a rebate program that covers up to 70% of the cost of retrofitting light fixtures that demonstrate a minimum 30% wattage reduction.  Commercial, industrial, agricultural, and institutional property owners are eligible for this incentive program, as are federal government agencies and nonprofits.

The Peninsula Light Company offers an incentive to its commercial customers who want to upgrade their lighting fixtures, as well.  It will cover a minimum of 30% of the cost of replacing inefficiently lights and a maximum of 70% of the project’s cost.  Finally, the Lighting Design lab offers energy analysis and technical assistance to commercial, industrial, and residential property owners across the entire Pacific Northwest to facilitate the switch to more energy-efficient lighting.

Wisconsin Lighting Discounts

Customers of Focus on Energy are eligible to receive discounts on ENERGY STAR products, including select lighting and LED lighting available through participating dealers.  The amount of these discounts varies by product but they are available to all Wisconsin business owners and property owners who participate in Focus on Energy.

Residential Programs

It’s clear that commercial growers across the United States have a variety of state-level programs available that can help them fund the switch to more energy-efficient grow lights, but hobby growers shouldn’t assume that they’ll just be left out in the cold.  Some states, including Massachusetts, Maine, Texas, and Wisconsin also provide rebates and cash incentives to residential property owners who want to switch over to more energy-efficient lights, including grow lights used for hobby cultivation.

What to Consider When Buying Energy-Efficient Grow Lights

Now that business owners who want to take their farming, cultivation, or propagation indoors know about what kinds of grow lights are available and what kinds of incentives may be available to fund the transition, it’s time to take a look at what to consider when purchasing new lights.  While some business owners who want to participate in the more restrictive of the rebate programs listed above may have fewer choices, most will have to carefully consider each possible option.  Don’t take a look at the price tags and just choose the lowest one, though, as different grow lights really are better for different applications.

Consider Project Duration

One of the first things to consider is how long the project will last.  Those companies that have already been growing indoors for years and already have a successful business model should make a point of purchasing grow lights that will last. 

LED grow lights can be expected to last for 50,000, versus only 20,000 for CMH lights.  While someone new to growing indoors and uncertain as to whether it will be economically feasible on a commercial scale might want to focus on per-watt growth estimates, light spectrum, and cost, long-term projects will provide a better ROI with a higher upfront investment.

Size of Operation

There are a few reasons that size really does matter.  First, small-scale indoor growers whose ceilings are less than eight feet high will need to carefully consider heat management, while large-scale commercial farmers who have access to full-sized warehouses or other much larger spaces don’t have to worry as much about excess heat.  Those working in small spaces might want to go with LED lights, since they put off minimal heat, while those working in industrial-scale buildings can opt for CMH or even HPS grow lights without worrying about burning their plants.

The current scale of the operation is also relevant in that hobby growers or small business owners typically have less money to invest in equipment up-front than large-scale agricultural operations.  Just don’t prioritize budget exclusively at the expense of quality and appropriateness of different lighting technologies.

Availability of Rebates and Incentives

Those property owners and business owners who live in states that offer rebates or cash incentives for energy-efficient lighting should be able to invest more money into upgrading their existing fixtures or installing new ones.  They’ll have to ensure that the lights they choose will meet the programs’ criteria, though. 

While each of the types of grow lights described at the beginning of this article provides impressive energy efficiency, some rebate programs only cover certain types of lights.  Many focus on LED lights to the exclusion of other types of lighting, which can make them impractical for indoor farmers and cultivators, depending on their particular needs.  If a rebate or cash incentive program doesn’t cover the type of lighting that will provide the best return on investment over time, it may not be worth participating in the program.

Other Factors to Consider

No matter what kind of lights growers choose to buy and where their agricultural operations or commercial businesses are located, they should always prioritize quality and efficiency over other concerns.  Other factors such as scalability and accessory requirements should also be considered prior to choosing new grow lights.

Look for Quality Lights From Trusted Manufacturers

Quality brands like Sun System, Gavita, Nanolux, DLI, Luxx, Revolution Micro, Dimlux, and Solis-Tek produce a wide variety of different grow lights that are known for their longevity as well as their efficiency.  Purchasing lights from an unknown company is never wise because it doesn’t come with the kind of quality guarantee that farmers can expect when they buy from trusted, established manufacturers.

Consider Scalability

Small business owners who are just dipping their toes in the water when it comes to indoor grows often begin by purchasing just a few lights and starting up a small-scale operation that will supplement their traditional crops.  Both HID and LED lights scale up relatively well.  It used to be the case that HID lights were considered the better option for business owners who wanted to plan for future growth, but recent advancements in LED technology and the availability of rebates and cash incentives in many locations has had a substantial impact on scalability.

Of course, this may be less of an issue for hobby growers who don’t ever plan on taking their projects to commercial markets, so CFL lights may be a reasonable option in this case.  Even hobby growers may want to look into LED lights, though, since they are extremely easy to use and they are the most energy-efficient option for grow lights at any scale.

Required Accessories

Grow lights that produce substantial heat in small spaces will only be practical if a fan can be installed in the area.  Fans aren’t the only accessories that may be necessary for some types of grow lights, though.  Some types of lighting will benefit from hot spot diffusers, while others will require reflectors in order to ensure that the plants are getting enough light.  Those who are looking for the simplest option often choose LED grow lights since there’s really no need for extensive accessorizing and they can usually just be plugged right into a wall outlet.

The Take-Away

Ultimately, deciding what type of grow lights to buy is a matter of balancing space requirements, scale, and intended use with budget to find the products that will offer business owners the best return on their investment and hobby growers the most satisfying experience for the least money.  As long as farmers and cultivators take these factors into account and purchase their lights from trusted manufacturers, they should be able to find a solution that will work for them.  Just make sure to investigate all possible options when it comes to rebates, discounts, and financing and work with a supplier that will answer any of its customers’ questions prior to finalizing the sale.

Grow lights have revolutionized how hobbyists and professional cultivators alike think about their options when it comes to growing plants.  It used to be the case that gardeners, farmers, and herbalists had to work within the fairly strict natural constraints of seasonal growing cycles, which greatly limited what kinds of plants could be grown in each location.  Today, though, it is not uncommon for growers to harvest their crops year-round.

Those who are just beginning to dip their toes in the water when it comes to indoor growing are often overwhelmed by the sheer number of options available to them when it comes to grow lights.  They don’t have to be, though.  Ultimately, each type of light has different pros and cons and is used in different circumstances, so all growers have to do to determine which of them will be the best fit is to consider all of the relevant details.

This article will offer a brief introduction to grow lights and how they are used, followed by a helpful breakdown of the different kinds of lights available and the pros and cons of each of them.  It will then offer some insight into energy savings credits and offer some best-practice advice for those who are new to indoor growers.  This information will allow even novice growers to begin their next season with the confidence that they have chosen the perfect light fixtures for their unique applications, so let’s dive in.

The Basics

What all grow lights have in common is that they are designed to stimulate plant growth indoors by providing the light required to facilitate photosynthesis.  They can be used year-round, or they can be placed in greenhouses to supplement the natural sunlight still available to plants by ensuring that they receive enough light to grow.  Without that extra light, plants grown in the winter would be impractically long and spindly even if they were being grown in full daylight.

The primary difference between different types of grow lights is the kind of light that they provide.  Some mimic the sun as accurately as possible, providing a light spectrum, color, temperature, and spectral outputs that is nearly identical to natural light.  Others are designed to mimic certain conditions under which plants will be better able to germinate or flower, providing more specific ranges of light spectrum, color, temperature, and lumen output.

There is no universal advantage to either sticking with one type of light that can be altered to provide different light value or changing the light source throughout the season.  Growers will need to have some idea of what kinds of plants they intend to cultivate prior to looking into grow lights, to begin with. 

Not sure exactly what kind of plants will be grown and just trying to get an idea of whether indoor grow lights will really provide a practical solution?  Those who are looking for more general information about grow lights and their many advantages can skip to the later sections of this guide.  For now, though, let’s take a look at the different categories of available lights.

High-Intensity Discharge (HID) Lights

HID grow lights feature large bulb systems designed to produce light through an ignition process.  There are three kinds of HID lights used for growing plants.  These are known as high-pressure sodium (HPS) lights, metal halide (MH) lights, and hybrid lights that use a combination of these technologies.

This category of grow lights has been growing substantially in recent years thanks to the high lumen-per-watt efficiency of HIDs.  Different types of HIDs produce different spectra of light, but all of them work on the same general principals.  They work by creating an electrical arc between two tungsten electrodes, causing the gas inside of the bulb to be ignited.

The general advantages of HID lights are that they provide high light intensity, are adjustable, and offer the highest yield per watt out of any category of conventional grow light.  That doesn’t make them perfect, though. Not all growers find their high yield constitutes enough of an advantage to overcome the several disadvantages associated with this class of lighting.

One of the largest disadvantages is that there is always a possibility of burning plants due to the fact that HID bulbs produce more heat than many of their alternatives.  They also require a good deal of additional equipment, including ballasts and reflectors, and the bulbs must be replaced over time.

Double-Ended (DE) Lights

DE grow lights are slightly different from the HID lights described above.  They still require ballasts, but instead of connecting to just one ballast port they actually connect to both ends.  This helps to explain their name.

Lights that form a single connection point to a ballast tend to become less efficient over time, while DE lights maintain 90% efficiency even after 10,000 hours of use.  It is important to note, however, that their general efficiency is reduced by nitrogen contact.

The best-known type of DE light is the high-pressure sodium (HPS) lighting system, although HPS lights can also be single-ended.  The double-ended kinds of HPS lights are often used in hydroponics, although they can certainly be put to good use in other indoor growing scenarios, as well.

The primary advantages of grow lights are their longevity, as noted above, and their slim design.  This feature allows them to provide more light than their single-ended counterparts and helps to spread the light more evenly across the plants.  The fact that DE lights don’t have metal, as do their single-ended counterparts, also means that all of the light produced is able to be transferred unhindered to the plants.

The primary disadvantages of DE lights are the efficiency reduction noted above and the fact that like HID lights, they can wind up burning plants.  DE lights can also be more expensive than their single-ended alternatives, especially when growers purchase the newest and most advanced models.

Fluorescent Lights

Quite popular among modern growers, fluorescent lights are cooler than both HID and DE lights.  This makes fluorescent grow lights perfect for propagating crops. 

Unfortunately, they’re less ideal for supporting plants in flowering or vegetative states, which means they can really only be used in conjunction with other types of grow lights.  The fact that they remain so popular despite this obvious disadvantage is a testament to how effective they truly are.

These lights are calibrated by diameter.  This helps to explain the “T” rating typically found after the name of a particular fluorescent bulb.  The “T” actually represents 1/8th of an inch, which means that a T5 fluorescent bulb will be 5/8ths of an inch in diameter.

As noted above, fluorescent lights are less than ideal for flowering and vegetative phases, which means they should really only be used for the specialized purpose of propagation.  The result of their inefficiency, when used in the later stages of growth, is that they also have the disadvantage of providing smaller yields per watt than other lights.  The ideal solution is, of course, to purchase fluorescent grow lights in addition to whatever lighting type growers choose for the remainder of their plants’ growth cycles.

The advantages of fluorescent lights are often considered to make them worth buying just for the propagation phase.  They’re long-lasting, energy efficient, able to cover a large surface area, and much more affordable than their alternatives.  Since fluorescent lights don’t produce as much heat, they may also be the only option for those growing in particularly short spaces.

LED Lights

LED lights are the comparative newcomers to the grow light game.  Many growers remain hesitant about purchasing these lights due to their higher initial cost, preferring to wait until their increased popularity makes LED lights more affordable.  Over time, though, even growers who purchase LED lights today will find that they will be provided with a solid return on their investments.

LED grow lights are energy-efficient and boast the lowest power costs of any grow light available on today’s markets.  They’re also long-lasting, which helps to make up for their higher cost over time, as well.  Other advantages of LED grow lights include their higher light production, the comparatively wide light spectrum that they provide, and their ease of use.

While many indoor growers find that LED lights are well worth the investment, not all of them find that the pros of LED lights outweigh their cons.  In addition to being more expensive due to their recent emergence on the market, they’re also less efficient than some of their alternatives for plants in their flowering phases.  On average, when they are used across a plant’s entire growth cycle, LED lights provide a slightly smaller yield per watt than their more conventional HPS alternatives, too.

Ceramic Metal Halide (CMH) Lights

CMH lights and their closest relatives the light emitting ceramics (LECs) are types of single-ended HID lights.  They’re both composed of ceramic elements and insulation and they’re both able to produce plenty of light to support even the vegetative and flowering stages of plants.  What most growers really like about CMH lights is that they are able to mimic natural sunlight very effectively in comparison to their alternatives, making them solid choices for all-purpose grow lights.  Single-ended CMH and LEC lights, which are so similar they’re actually interchangeable in most systems, also last longer than double-ended lights.

While these lights compare reasonably favorably to other lighting types, they’re not perfect.  They do require magnetic ballasts and they produce a good deal of heat, which often necessitates tall ceilings and accessories like fans.  They also expose plants to relatively high rates of UV light.

 

Federal Energy Savings Incentives

The Energy Independence and Security Act (EISA) passed by the United States Federal government in 2007, could be said to be at least partially responsible for the notable increase in the availability of high-efficiency lighting in recent years.  This Act required manufacturers to increase their products’ efficiency by at least 27 percent over the then-popular traditional incandescent bulbs.

Of course, this Act only benefits consumers indirectly and really, it only benefits those consumers who choose to buy fluorescent grow lights, LEDs, and other energy-efficient models.  The Department of Energy also developed the Better Buildings Outdoor Lighting Accelerator relatively early on in 2014 to incentivize public agencies and municipalities to install energy-efficient, high-performance lights.  Although this program stopped receiving funding in 2016, it did help the government assess barriers to increasing lighting efficiency among municipalities and continues to be used as a reference for the development of future plans.

The National Mortgage Association also provides a federally-funded incentive program.  This program, operated through the Fannie Mae Multifamily Green Financing Business, provides financial funding for energy efficiency improvements made on multifamily residential properties and cooperatives.  While these programs certainly constitute a step in the right direction, the direct-to-consumers incentive for purchasing more energy-efficient grow lights comes from individual states, not the Federal government.

State Energy Incentives

As of 2016, only 14 states were without some sort of energy efficiency incentive program that included lighting efficiency.  Even in these states, local governments may still provide grants, loans, or other forms of financial incentive to consumers on a city- or county-wide basis rather than a state-wide basis.  One example can be seen in the Property Accessed Clean Energy (PACE) program in the City of Winter Park, Florida.  This program offers consumers rebates when they upgrade their indoor lighting to use more energy-efficient technologies and provides funding to both residential and commercial business owners.

Of those 36 states that have enacted legislation that offers incentives for energy-efficient lighting or adopted incentives to accomplish the same goal, 12 have rebate programs that reimburse consumers directly, eight offer grants to local and state-level agencies and organizations, and five that offer sales tax exemptions for purchasing energy-efficient lighting.

State-Enacted Legislation

Six states enacted energy-efficient lighting legislation between the years 2013 and 2016.  Most of these Acts were drafted with town and county municipalities in mind.  Overall, though, the following states’ legislative efforts reflect a trend toward increasing state efforts to finance energy efficiency programs at all levels.

Alabama Senate Bill 220

In 2015, Alabama passed Senate Bill 220 to enable PACE financing.  This, in turn, has allowed many counties and municipalities throughout the state to finance improvements in energy efficiency.  Lighting projects are explicitly included as qualifying projects under Senate Bill 220.  The financing is issued through assessments on each property owner’s tax bill.

Arkansas Senate Bill 869

Arkansas also passed legislation in 2015 to support improvements in energy efficiency on a municipal level.  Senate Bill 869 authorizes the state to offer bonds for use financing energy efficiency projects, including lighting projects.

Kentucky House Bill 100

In 2015, the Kentucky state government passed House Bill 100 to enable PACE financing.  Like Alabama’s Senate Bill 220, Kentucky’s House Bill 100 allows counties and municipalities to take advantage of financing for energy efficiency improvement projects, including lighting.  Also like Alabama, Kentucky provides its financing through property tax bill assessments.

Maryland House Bill 786

Maryland passed its energy-efficiency project financing legislation in 2014.  House Bill 786 adds LED bulbs to the state’s existing list of energy efficient products that are exempt from taxes when purchased during President’s Day weekend.  Unfortunately, this Act expired automatically in 2017.

Nebraska Legislative Bill 1012

Legislative Bill 1012 was passed in Nebraska in 2016.  Like many of the other state-level legislative changes described above, it was designed to enable PACE financing for a wide array of energy-efficiency improvements, including lighting.

Rhode Island House Bill 5935 and Senate Bill 836

Rhode Island began to pass state-level legislation surrounding energy efficiency in 2013, making it one of the earlier adopters of energy improvement laws.  This piece of legislation created the Municipal Streetlight Investment Act, which, in turn, allows for the purchase of energy-efficient street lighting by municipalities at a reduced cost.  House Bill 5900, passed in 2015, extended the state’s existing public funding for renewable energy.

Rhode Island Executive Order 15-17

Rhode Island’s Executive Order 15-17 goes farther than the other legislative Acts described above when it comes to ensuring energy efficiency on a town and county level by establishing explicit energy efficiency goals for these state facilities.  According to this Executive Order, Rhode Island’s municipal facilities will have to be procuring 100% of their electricity from renewable resources by 2025.  Although it only applies to municipal organizations, Executive Order 15-17 does cover lighting efficiency projects.

Energy-Efficient Lighting Incentives

Many of those states that have not passed legislation regarding the financing of lighting efficiency projects still offer incentives to organizations and consumers to improve the efficiency of their lighting and these incentives are available to indoor growers.  27 of these programs implement low-interest or even zero-interest loans, while 12 enact consumer rebate programs, eight offer grants to local governments, and five offer tax exemptions for energy-efficient lighting. 

The NC Clean Energy Technology Center has compiled a comprehensive list of energy savings programs by state available through DSIRE USA.  Those who don’t want to spend hours searching through databases can also check out this state-by-state breakdown of the most relevant of these incentive programs below.

Fort Morgan, Colorado

The Municipal Energy Agency of Nebraska has partnered with Fort Morgan’s local municipal utility companies to offer cash incentives to commercial business owners interested in replacing their less efficient lights with more energy-efficient alternatives.  Energy-efficient grow lights are eligible under this program if they will be used for commercial farming or cultivation.  Eligible applicants will receive their cash incentives within four to six weeks after submitting their receipts.

State of Idaho

Rocky Mountain Power in Idaho offers rebates for energy-efficient lighting installations in addition to providing technical assistance for small businesses.  This program’s cash incentives can be applied to lighting retrofits, new construction, and renovation alike.

Illinois Rebate Programs

Ameren Illinois Utilities manages a rebate program for commercial, industrial, nonprofit, the federal government, and agricultural customers interested in upgrading to energy-efficient lighting.  The maximum cash incentive available through the program is $500,000 per project and it can be applied to any new construction, remodel, or retrofit.  Illinois indoor growers should know that any incentive request for more than $10,000 will need to be pre-approved by the utility company, though.

The state of Illinois offers a second rebate program managed by Commonwealth Edison Co and funded by the Illinois Energy Efficiency Portfolio Standard (EEPS) surcharge, as well.  Eligible technologies include LED lighting and other forms of energy-efficient lighting.  Only commercial, industrial, and federal government customers are eligible for this rebate, though. 

Minimum efficiency requirements for LEDs and other lights vary substantially under this rebate program.  The minimum incentive for eligible LED lighting is $5.00 per unit and the maximum is $20.00 per unit.  The minimum incentive for other forms of energy efficient lighting is $1.00 per lamp, while the maximum is $55.00 per lamp. 

Massachusetts Rebate Programs

The town of Reading in Massachusetts offers a rebate program that applies to lighting and lighting controls or sensors.  Rebates are available to a wide variety of organizations, including commercial and industrial businesses, local governments, nonprofits, and schools.  Most importantly, the rebate program is explicitly available to commercial indoor agricultural operations. 

The maximum incentive amount is either $25,000 per year or 50% of the purchase price of the eligible fixtures, which must achieve at least 25% energy savings.  The incentive for energy-efficient lighting, including grow lights, ranges from $10.00 per unit to $350.00 per unit, while the incentive for lighting controls and sensors ranges from $15.00 per unit to $60.00 per unit.

Rowley, Massachusetts also offers a rebate program for commercial businesses.  The program, funded by the Rowley Municipal Lighting Plant, offers cash rebates of up to $300 for commercial energy audits and provides funding for as much as 75% or up to $1,500 per audit of those measures recommended to improve efficiency, including energy-efficient lighting.

Minnesota Incentives

There are a variety of municipal utility companies in Minnesota that offer cash incentives to commercial customers who make the switch to eligible energy-efficient technologies, including lighting.  These cash incentives can be applied to both retrofitting projects and new construction.

Missouri Rebates

Columbia, Missouri offers rebates to commercial and industrial property owners who switch to more efficient lighting.  The maximum incentive is the lesser of either $22,500 or the cost of a 75 kW reduction.  Eligible customers must plan to achieve a 1-75 kW energy reduction when they switch to new lights and must undergo an audit prior to receiving their rebates.

Columbia is not the only city in Missouri that offers a rebate program.  The Southwest Electrical Cooperative also administrates an energy-efficient commercial lighting rebate program called the Take Control and Save Program.  An audit will still have to be performed prior to the issuance of any rebates.

Montana Rebates

The Flathead Electric Cooperative and Bonneville Power Administration offer a rebate program to commercial, industrial, and agricultural business owners who want to retrofit existing facilities with more energy-efficient lights or install energy-efficient lights in new buildings.  The administrator must approve rebates prior to the installation but the cost of those light fixtures that are deemed eligible, including energy-efficient grow lights, can be covered by as much as 70%.

North Carolina Rebate

The Randolph Electric Membership Corporation offers a rebate program for commercial and industrial property owners that make the switch to more energy-efficient lighting.  The rebate offers a set price of $0.30 per watt of energy saved by the new lights.  This can add up to a good deal of money for indoor farmers and cultivators in North Carolina.

New York Incentives

New York state has two incentive programs for small business owners.   One is funded by System Benefits Charge and administered by Rochester Gas and Electric Corporation.  Rochester area business owners whose electricity demands average less than 110 kW per month may be eligible to take part in this program, which will pay for up to 70% of the cost of lighting retrofits.

The second New York state incentive program also offers free energy assessments and covers up to 70% of the cost of lighting retrofits but it is available to small business owners across the state.  System Benefits Charge also funds this second program but it is administered by New York State Electric and Gas Corporation.  In both of these cases, small business owners who are interested in finding out their eligibility status will have to schedule a free energy assessment prior to moving forward with their retrofits.

Oregon Incentives

The Springfield Utility Board administers a cash incentive program available to commercial and industrial business owners, nonprofits, and government offices operating in the City of Springfield.   The amount of these incentives varies substantially, as does eligibility.  In order to be eligible, the expected savings from a retrofit or new construction must be at least 20% and the lighting equipment has to be on the administrator’s qualifying products list.

Tillamook County People’s Utility District also offers an incentive program for commercial, industrial, and agricultural customers who are switching to more efficient lighting.  The first step toward determining eligibility is to schedule a lighting analysis.  Only retrofits are eligible for this rebate program, not new construction.

A third entity, the Oregon Trail Electric Consumers Cooperative, offers a more inclusive retrofit company to Oregon commercial property owners.  The rebates can cover up to 70% of the cost of retrofitting existing lighting.

San Marcos, Texas

The City of San Marcos offers a rebate program that covers $250 per kW of energy reduction when commercial, industrial, institutional, or multifamily residential property owners switch to more energy-efficient lighting.  The maximum incentive for this program is $12,500.  Only lighting controls or sensors and the LED lighting are considered eligible technologies.

Vermont Rebates

Vermont offers two different rebate programs, one of which is available to commercial, industrial, institutional, and agricultural property owners, federal government offices, schools, and nonprofits and the other of which is only available to agricultural operations. 

The first of these rebate programs, offered by Efficiency Vermont, covers up to 100% of the purchase price of new lighting equipment that meets eligibility requirements.  Eligible lighting includes ENERGY STAR LED replacement lamps, fixtures, and retrofit kits as well as DLC replacement lamps.  The latter of these programs is also offered by Efficiency Vermont.  Agricultural operations can get rebates of between $25 and $75 for each new lighting fixture and between $20 and $150 for each new LED lighting fixture.

Washington State

There are several rebate programs for Washington state commercial indoor growers who want to upgrade their lights depending on what areas they live in.  The City of Richland offers a rebate program that covers up to 70% of the cost of retrofitting light fixtures that demonstrate a minimum 30% wattage reduction.  Commercial, industrial, agricultural, and institutional property owners are eligible for this incentive program, as are federal government agencies and nonprofits.

The Peninsula Light Company offers an incentive to its commercial customers who want to upgrade their lighting fixtures, as well.  It will cover a minimum of 30% of the cost of replacing inefficiently lights and a maximum of 70% of the project’s cost.  Finally, the Lighting Design lab offers energy analysis and technical assistance to commercial, industrial, and residential property owners across the entire Pacific Northwest to facilitate the switch to more energy-efficient lighting.

Wisconsin Lighting Discounts

Customers of Focus on Energy are eligible to receive discounts on ENERGY STAR products, including select lighting and LED lighting available through participating dealers.  The amount of these discounts varies by product but they are available to all Wisconsin business owners and property owners who participate in Focus on Energy.

Residential Programs

It’s clear that commercial growers across the United States have a variety of state-level programs available that can help them fund the switch to more energy-efficient grow lights, but hobby growers shouldn’t assume that they’ll just be left out in the cold.  Some states, including Massachusetts, Maine, Texas, and Wisconsin also provide rebates and cash incentives to residential property owners who want to switch over to more energy-efficient lights, including grow lights used for hobby cultivation.

What to Consider When Buying Energy-Efficient Grow Lights

Now that business owners who want to take their farming, cultivation, or propagation indoors know about what kinds of grow lights are available and what kinds of incentives may be available to fund the transition, it’s time to take a look at what to consider when purchasing new lights.  While some business owners who want to participate in the more restrictive of the rebate programs listed above may have fewer choices, most will have to carefully consider each possible option.  Don’t take a look at the price tags and just choose the lowest one, though, as different grow lights really are better for different applications.

Consider Project Duration

One of the first things to consider is how long the project will last.  Those companies that have already been growing indoors for years and already have a successful business model should make a point of purchasing grow lights that will last. 

LED grow lights can be expected to last for 50,000, versus only 20,000 for CMH lights.  While someone new to growing indoors and uncertain as to whether it will be economically feasible on a commercial scale might want to focus on per-watt growth estimates, light spectrum, and cost, long-term projects will provide a better ROI with a higher upfront investment.

Size of Operation

There are a few reasons that size really does matter.  First, small-scale indoor growers whose ceilings are less than eight feet high will need to carefully consider heat management, while large-scale commercial farmers who have access to full-sized warehouses or other much larger spaces don’t have to worry as much about excess heat.  Those working in small spaces might want to go with LED lights, since they put off minimal heat, while those working in industrial-scale buildings can opt for CMH or even HPS grow lights without worrying about burning their plants.

The current scale of the operation is also relevant in that hobby growers or small business owners typically have less money to invest in equipment up-front than large-scale agricultural operations.  Just don’t prioritize budget exclusively at the expense of quality and appropriateness of different lighting technologies.

Availability of Rebates and Incentives

Those property owners and business owners who live in states that offer rebates or cash incentives for energy-efficient lighting should be able to invest more money into upgrading their existing fixtures or installing new ones.  They’ll have to ensure that the lights they choose will meet the programs’ criteria, though. 

While each of the types of grow lights described at the beginning of this article provides impressive energy efficiency, some rebate programs only cover certain types of lights.  Many focus on LED lights to the exclusion of other types of lighting, which can make them impractical for indoor farmers and cultivators, depending on their particular needs.  If a rebate or cash incentive program doesn’t cover the type of lighting that will provide the best return on investment over time, it may not be worth participating in the program.

Other Factors to Consider

No matter what kind of lights growers choose to buy and where their agricultural operations or commercial businesses are located, they should always prioritize quality and efficiency over other concerns.  Other factors such as scalability and accessory requirements should also be considered prior to choosing new grow lights.

Look for Quality Lights From Trusted Manufacturers

Quality brands like Sun System, Gavita, Nanolux, DLI, Luxx, Revolution Micro, Dimlux, and Solis-Tek produce a wide variety of different grow lights that are known for their longevity as well as their efficiency.  Purchasing lights from an unknown company is never wise because it doesn’t come with the kind of quality guarantee that farmers can expect when they buy from trusted, established manufacturers.

Consider Scalability

Small business owners who are just dipping their toes in the water when it comes to indoor grows often begin by purchasing just a few lights and starting up a small-scale operation that will supplement their traditional crops.  Both HID and LED lights scale up relatively well.  It used to be the case that HID lights were considered the better option for business owners who wanted to plan for future growth, but recent advancements in LED technology and the availability of rebates and cash incentives in many locations has had a substantial impact on scalability.

Of course, this may be less of an issue for hobby growers who don’t ever plan on taking their projects to commercial markets, so CFL lights may be a reasonable option in this case.  Even hobby growers may want to look into LED lights, though, since they are extremely easy to use and they are the most energy-efficient option for grow lights at any scale.

Required Accessories

Grow lights that produce substantial heat in small spaces will only be practical if a fan can be installed in the area.  Fans aren’t the only accessories that may be necessary for some types of grow lights, though.  Some types of lighting will benefit from hot spot diffusers, while others will require reflectors in order to ensure that the plants are getting enough light.  Those who are looking for the simplest option often choose LED grow lights since there’s really no need for extensive accessorizing and they can usually just be plugged right into a wall outlet.

The Take-Away

Ultimately, deciding what type of grow lights to buy is a matter of balancing space requirements, scale, and intended use with budget to find the products that will offer business owners the best return on their investment and hobby growers the most satisfying experience for the least money.  As long as farmers and cultivators take these factors into account and purchase their lights from trusted manufacturers, they should be able to find a solution that will work for them.  Just make sure to investigate all possible options when it comes to rebates, discounts, and financing and work with a supplier that will answer any of its customers’ questions prior to finalizing the sale.

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