Energy-Efficient Lighting for the Farm


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Energy-Efficient Lighting for the Farm

  1. 1. The National Sustainable Agriculture Information Service, ATTRA (, was developed and is managed by the National Center for Appropriate Technology (NCAT). The project is funded through a cooperative agreement with the United States Department of Agriculture’s Rural Business- Cooperative Service. Visit the NCAT website ( sarc_current.php) for more information on our other sustainable agriculture and energy projects. Funding for the development of this publication was provided by the USDA Risk Management Agency. 1-800-346-9140 • www.attra.ncat.orgA project of the National Center for Appropriate Technology By Leif Kindberg NCAT Farm Energy Specialist © 2010 NCAT Contents Energy-Efficient Lighting for the FarmEnergy-efficient lighting options present farmers with new opportunities to reduce electricity costs and help manage farms sustainably. Cost-effective energy-efficient lighting can be used to improve produc- tivity and safety, and reduce operating costs. This publication provides an overview of energy-efficient lighting technology and explains how to select lighting options that are appropriate for the farm. Introduction Lighting is an essential part of most farms. Even so, most farms do not use it as an opportunity to reduce energy costs. Energy-efficient lighting may offer inexpensive opportunities for farms to reduce energy costs and improve productivity. Energy-efficient lighting technologies are avail- able in many sizes and types, including linear fluorescent lamps, compact fluorescent lamps (CFL), induction lighting, pulse-start metal halide lamps, high- and low-pressure sodium vapor lamps, light-emitting diodes (LED), daylighting tubes, and skylights. These long- life technologies can reduce costs in two ways: lower fixed costs through fewer replacements and lower operating costs through lower energy consumption. Electronic ballasts, lighting controls, and proper reflectors further improve the efficiency, quantity, and quality of light used on the farm. This publication will introduce you to energy- efficient lighting technologies, and terms used by the lighting industry, and help you select options that meet your farm’s lighting requirements. The term lamp is interchanged with the term light bulb throughout this publication. Light Quantity Measuring the light level (also thought of as bright- ness or quantity of light) is helpful to determine the type of lamp you need. Light output is mea- sured in different ways. It might be measured in the units of light leaving the lamp (lumens), or it might be measured by the amount of light falling on a surface (foot-candles). Foot-candles are the common method of measuring light quantity in agricultural operations. The foot-candle (fc) is the light level at the work- ing surface and is defined as the amount of illu- mination from a candle falling on a surface at a distance of one foot. Outside on a bright Efficient lighting can help reduce farm energy costs. Photo by Andy Pressman. Introduction......................1 Light Quantity..................1 Light Quality .....................2 Focus on Efficiency.........3 Fixtures ...............................4 Ballasts ................................4 Lamps..................................4 Daylighting........................7 Energy Conserving Controls...............................7 Lighting Greenhouses.....................7 Lighting for Alternative Poultry Production.........................8 Dairy Lighting...................9 Lighting Disposal ............9 Summary............................9 References .......................11 Resources.........................11
  2. 2. Page 2 ATTRA Energy-Efficient Lighting for the Farm Light quality is generally measured by color temperature and color rendering index (CRI). Color temperature (also called correlated color temperature, CCT) is measured in degrees Kelvin (K). A higher color temperature num- ber indicates that a lamp will emit a more blue or cooler light, and a lower color temperature number indicates that a lamp will emit a more orange/red or warmer light. This is sometimes confusing, but just remember that a higher color temperature is more like sunlight. Most man- ufacturers provide a color description on the packaging such as “warm white” or “cool blue.” A cool, white light might have a color temper- ature of 3,500 degrees Kelvin or above, and a warm, yellow lamp might have a color tempera- ture of less than 3000 degrees Kelvin. Color rendering index (CRI) is a measurement of how a light source will reproduce colors of vari- ous objects in comparison with sunlight. Some tasks on the farm, such as produce sorting, require light that makes colors appear as they would in sunlight. Be aware that CRI is mea- sured at any given lamp’s color temperature and is therefore more difficult to use as a comparison between lamps with different color temperatures. CRI is measured on a scale of 0 to 100. The larger the CRI value, the closer the lamp renders a color the same as sunlight. A value of 0 means that col- ors all look the same under the lamp. Although lamp output or quantity of light is important, light quality characteristics like color temperature and CRI also affect your per- ception of light quantity and comfort. Both of these characteristics should be considered when replacing a lamp. sunny day in midsummer, the light level will be around 8,000 fc. Inside, a brightly lit desk-top surface will be about 100 fc. A dimly lit street at night may be at one fc or less. This is what light meters measure, and it is equivalent to one lumen per square foot. Lumen flux is the quantity of light that leaves the lamp, and is measured in lumens (lm). All lamps are rated in lumens and may be rated in both initial and mean lumens. The mean lumens of a lamp provide the average rated output over the lamp’s rated life. The initial and mean lumens may be used to compare one lamp with another. The lumen output of a lamp is printed on the package of most lamps and will be discussed further. The light loss factor (LLF) is the measure of a lamp’s lumen output near the end of its use- ful life in comparison to the lumen output pro- vided by the manufacturer. Lamps decrease in output because lamp and ballast components degrade over time due to normal operation and environmental factors such as dust buildup. LLF may be measured and presented in many ways. It is important to remember that lamps may need to be selected for a higher-than- needed light level or replaced before they burn out to take into account light loss as the lamp and its components age. Average rated life, usually determined under lab- oratory conditions, is the point at which some percentage of the initially installed lamps have burned out. The operating conditions that affect the average rated life lamp include ambient tem- perature, humidity, dust, power surges, and switching the lamp on and off. Light output and light quality (discussed next) change over time for almost all lamps. Therefore, considerations such as color shifting, lumen depreciation, and loss in luminous efficacy (an industry term for efficiency) may reduce average rated life and should be taken into account. Light Quality Understanding light quality (also thought of as brightness or light color) is important for farms that are using light to manage the photo-period and activity of livestock. A balance among ani- mal health, comfort, and productivity should be considered. (ATTRA offers a variety of publica- tions on sustainable livestock production. Visit for more information.) Related ATTRA publications Farm Energy Calculators: Tools for Saving Money on the Farm Efficient Agricultural Buildings: An Overview Solar Greenhouses Comparing Energy Use in Conventional and Organic Cropping Systems Poultry House Management for Alternative Production Dairy Farm Energy Efficiency Color temperature is a scale of color (not brightness) rated in Kelvin. 12000K 7000K 4000K 3000K 2000K 6 5500K Midday 5000 - 6500K Natural or Daylight 4100K Moonlight 3500 - 4100K Cool White, Bright White 2700 - 3000K Warm White, Soft White 1850 - 2000K Candlelight 6500 - 7500K Overcast Sky
  3. 3. Page or less in applications where the lights are oper- ated eight hours a day or more. (ASABE, 2005) Determining lamp efficiency can be accom- plished in a several ways. To determine the luminous efficacy (lumens per watt), look at the package and divide the number of lumens by the wattage. For example, a 23-watt (W) com- pact fluorescent lamp produces about 70 lumens per watt (70 lm/W) for a total of about 1,600 lumens, where watts is the rate of electric power required to operate at peak output. For compari- son, a 100-watt incandescent light lamp might produce only 10 lumens per watt, making it sig- nificantly less efficient in comparison to a com- pact fluorescent lamp. Another quick way of choosing an efficient lamp is to find lamps with the light output (lumens) you need, and then choose the lamp that uses the fewest watts. Focus on Efficiency Energy efficiency in lighting is referred to as effi- cacy and is measured in lumens per watt (lm/w). Efficacy is somewhat like measuring miles per gallon. The more lumens you can get from a watt of power, the more efficient the lamp and the more you will likely save on your electricity bill. Efficacy is the ratio of light output from a lamp to the electricity it uses. There are two major cost-efficiency consid- erations: the cost of operating the lamp and the cost of replacing the lamp. In most cases, replacing an existing lamp with one which has a higher luminous efficacy and longer average rated life will reduce operating costs and may also reduce replacement costs. Energy-efficient lighting will typically pay for itself in two years Compare the energy cost savings of different lamps by determining the amount of energy the lighting system will consume. Con- sider the example of operating 10 CFL vs. 10 incandescent lamps for 7 days/week, 14 hours/day, and for 40 weeks per year. To determine the energy consumption of this or any lighting system, multiply input wattage (W) by time (hours of operation during a year). To help choose which lamps to install, calculate the annual operating costs. Adjust the operating hours or lamp wattage so this example matches your lighting needs. Table 1: Energy cost comparison Other lighting considerations not included in this example may be relevant to your application. Developed from manufacturer literature and pricing. Type of Lamp CFL Type of Lamp Incandescent Input Wattage 24 W Input Wattage 100 W Lumen Output 1,380 lm Lumen Output 1,026 lm Efficacy 57.5 LPW 1,380 lm ÷ 24 W Efficacy 10.26 LPW 1,026 lm ÷ 100 W Operating Hours 3,920 h 7 days/week x 14 hours/ day x 40 weeks/year Operating Hours 3,920 h 7 days/week x 14 hours/day x 40 weeks/year Energy Use 94,080 Wh 24W x 3,920 hrs/year Energy Use 392,000 Wh 100W x 3,920 hrs/year Energy Use 94.08 kWh 94,080 watt-hours (Wh) ÷ 1,000 = 94.08 kilowatt-hours (kWh) Energy Use 392 kWh 392,000 watt-hours (Wh) ÷ 1,000 = 392 kilowatt-hours (kWh) Utility Charge/ kWh $0.0928 Utility Charge/ kWh $0.0928 Energy Cost/Year $8.73 94.08kWh x $0.0928/ kWh Energy Cost/Year $36.38 392kWh x $0.0928/kWh Lamp Cost $3.95 Lamp Cost $0.48 Annual Operating Costs $87.30 # of lamps x $8.73 Annual Operating Costs $363.80 # of lamps x $36.38
  4. 4. Page 4 ATTRA Energy-Efficient Lighting for the Farm lamp, a rated wattage different from that listed with the lamp should be considered. This new rated wattage will be published by the ballast manufacturer. In general, ballasts for fluores- cent lamps are either magnetic or electronic. Electronic ballasts are more efficient and now considered to be the industry standard. Lamps Energy-efficient lamps are available in many dif- ferent shapes and sizes, with a broad selection of light color temperatures, lumen outputs, and color rendering qualities. Lamp replacement is generally “do-it-yourself” on the farm, but bal- last and fixture replacement requires experience with AC electrical. Incandescent Incandescent lamps are the least expensive and most commonly available lamps. Incandes- cent lamps create light by resistance to the flow of electricity through finely coiled wires that become hot enough to glow. However, they are also the least efficient. About 90 percent of the energy used by an incandescent lamp becomes heat, and only 10 percent becomes light. (Hiatt, 2008) Incandescent lamps generally have a very short average-rated life. Their short life and poor use of energy make them inefficient and some- times costly to operate. Tungsten-halogen Tungsten-halogen (or just halogen) lamps are a type of high-pressure incandescent lamp that is more energy-efficient than a regular incandes- cent lamp. Halogen lamps operate at very high temperatures and use less energy by recycling heat to keep the filament hot with less elec- tricity. Halogen lamps can be used with many dimmers and do not take any time to warm up. (ASABE, 2005) Read the instructions carefully before handling halogen lamps. Compact Fluorescent (CFL) CFLs last up to 10 times longer and may use 75 percent less energy than the common incandescent lamp. (U.S. Department of Energy, 2006) CFLs may have a single spiral tube, multiple tubes, or tubes covered to look similar to an incandescent light. Regular CFLs have a hot cathode (electrode) made of tungsten wire that is coated with barium carbonate. The cathode emits electrons that pass Fixtures Fixtures generally consist of a frame, lamp sock- ets, and lamp(s) but may also include a ballast, reflector, diffuser, or other hardware. Lamp fix- tures are very important to the quantity and quality of light provided as well as efficiency and safety. The number and placement of fixtures should be carefully matched to the application for the best efficiency. Fewer fixtures with higher wattage lamps will produce greater variation in light. More fixtures with lower wattage lamps will provide greater uniformity in the light. Reflectors and reflector geometry help trap less light in the fixture and push more light out of the fixture, improving light quantity. A lamp fixture with a reflector, for example, directs more of the light to the area where it is required, and in some cases allows lower wattage lamps to be used. It is not uncommon in the typical yard light for 30 percent of light to be wasted due to inefficient fixtures that may let light go up or out from the lamp. (Sanford, 2004a) Similarly, diffusers can be used on many types of lamps to distribute light horizontally. Agricultural fixtures should be resistant to cor- rosion, moisture, and dust. For a lamp in a wet location, a sealed polycarbonate or other gas- keted and weatherproof enclosure should be installed. The enclosure should be approved for use with the lamp, especially CFL lamps, to pre- vent fire hazards and premature lamp failure. Ballasts The purpose of a ballast is to provide the voltage necessary to initiate lighting in gas-discharge and some other lamps. Lamps that require a bal- last for start-up include high- and low-pressure sodium, fluorescent, induction, mercury-vapor, and metal halide lamps. Ballasts function by heating electrodes with low voltage or in some cases supplying very high voltage to start the lamp. Once the lamp is started, the ballast controls the voltage to the lamp to sustain the light discharge. Because ballasts increase or decrease the voltage to the You may wish to use the Natural Resources Conservation Service (NRCS) Energy Self Assessment tool conservation/default.aspx for lighting to help you choose energy-efficient lighting.
  5. 5. Page and ballast, the T-8 fluorescent lamp provides about 15 percent more lumens per watt, and the ballasts are 40 percent more efficient. (Sanford, 2004) Both T-8 and T-12 lamps can be used in sealed fixtures needed in most farm applica- tions. Most magnetic ballasts used with T-12 lamps will no longer be manufactured after July 1, 2010. They can be replaced with higher effi- ciency electronic ballasts or with more efficient fixtures and lamps like the T-8. High-output versions of linear fluorescent lamps will start in temperatures as low as -20 degrees Fahrenheit but are less efficient than regular lin- ear fluorescent lamps. These lamps use a double recessed contact instead of the traditional bi-pin or single pin contact used with standard fixtures. High-output lamps use a special ballast as well. Ambient temperatures affect fluorescent lamps. The minimum starting temperature for standard fluorescent lamps is 50 F. (ASABE, 2005) High output lamps are generally not required unless the lamp will experience recurring starting tem- peratures of 50 degrees Fahrenheit or below. Although T-5 lamps are even more efficient than T-12 and T-8 lamps, they also produce more heat than larger-diameter lamps and cannot be used in sealed fixtures. Sealed and weatherproof fixtures are necessary in many areas with live- stock, moisture, or dust. For these reasons, T-5 lamps are generally not recommended for agri- cultural applications. Lamps and ballasts should be upgraded together. Fixtures that are the same length can be con- verted from a T-12 lamp to a more efficient T-8 lamp with a new ballast and lamps. The sockets for T-12 and T-8 lamps are usually either a sin- gle pin or medium bi-pin and must be matched with the lamp. The double recessed contacts used by high-output lamps must be replaced when converting to more efficient T-8 lamps. through a mercury vapor and generate light. A tube with a larger surface area will generally emit more light. Most CFLs will not operate below 0 degrees Fahrenheit and require about a minute to reach full output. CFLs make a good replacement for many farm applications. Another type of compact fluorescent lamp, cold cathode fluorescent light (CCFL), is widely used in the poultry industry. Cold cathode lamps oper- ate in the same way as regular CFLs but last two to three times longer, are compatible with many types of dimmers, start at lower temperatures than regular CFLs, and can be turned on and off without sig- nificantly shortening the lamp life. (Tabler, 2009) The unheated cathode of a CCFL requires more energy to release the electrons. As a result, cold cathodes are slightly less energy-efficient than a regular CFL. They are also more expensive than most other CFLs. The long life of these lamps will potentially offset the higher initial cost, especially when replacing incandescent lamps. Cold cathode and regular CFL lamps are direct replacements for incandescent lamps with the same medium screw base. Linear Fluorescent Linear fluorescent lighting is commonly used in shops, barns, and other covered spaces. The most common designations for linear fluores- cent lighting include T-5, T-6, T-8, T-10, T-12 and T-17. The T indicates the shape of the lamp tube, and the corresponding number indicates the tube diameter in eighths of an inch. A T-8 lamp is tubular and 8/8” (1 inch) in diameter. The T-8 lamps are the most energy-efficient option (usually 75 to 98 lm/W) commonly used in farm applications. Compared to a T-12 lamp A T-8 linear fluorescent lamp with medium bi-pin contacts. Photo by Leif Kindberg. Two T-12 linear fluorescent lamps with a single pin contact. Photo by Leif Kindberg. T he T-8 lamps are the most energy-efficient option (usually 75 to 98 lm/W) commonly used in farm applications.
  6. 6. Page 6 ATTRA Energy-Efficient Lighting for the Farm High- and Low-Pressure Sodium Vapor (HPSV & LPSV) High-pressure sodium vapor lamps are more efficient (usually 50 to 140 lm/W) than metal halide lamps. They emit a yellow-orange light and have a low CRI, making them less desir- able for areas where color recognition is needed. HPSVs are often used for street and security lighting where color quality is less important. They may also work well for side sheds, lighting pathways between buildings, and general out- door lighting needs. HPSVs perform well at cold temperatures (21 degrees Fahrenheit and below). (ASABE, 2005) Low-pressure sodium lamps (LPSV) may be slightly more efficient than HPSVs (usually 60 to 150 lm/W). Their color rendering qualities are lower than HPSVs. LPSVs may work where very dim lighting is required such as in secu- rity lighting, road lighting and other indoor/ outdoor applications. Mercury Vapor (MV) Mercury vapor lamps emit a greenish-bluish light similar to daylight and are commonly used as security lights. MV lamps have low color-ren- dering properties and the lowest efficiency of any of the HID lamps (usually 25 to 60 lm/W). In addition, mercury vapor lamps create an environmental risk due to the mercury gas they contain. High-pressure sodium vapor lamps are more efficient than mercury vapor lamps but require a different ballast. Light Emitting Diode (LED) LEDs are energy-efficient lamps commonly used in home electronics, road signs, accent Induction Induction lighting is a type of fluorescent light that does not have electrodes or filaments like other types of lamps. Induction lighting works well in hot and cold environments with mini- mal loss of light output and is less sensitive to heat than other types of lighting. Induction lamps use a ballast, a coupling device to gener- ate a magnetic field, and a special type of lamp globe. The mercury in the globe is excited by the magnetic field and emits light. Induction lamps are very efficient (usually 50 to 90 lm/W) and may have a rated life of 100,000 hours or more. They switch on almost instantly and do not need to cool down before re-strik- ing, unlike many other light systems. Induction lighting costs more than most other lighting sys- tems and may work well in areas where chang- ing burned-out lamps is difficult or expensive. (U.S. Department of Energy, 2006) Metal Halide Metal halide, high-pressure sodium vapor, and mercury vapor lamps are all considered high intensity discharge (HID) lamps. These lamps are not suited for applications where light is needed only for short durations due to their long warm-up time. These lamps do not burn out the same way other lamps do. Most HID lamps should be replaced when they begin to fade (metal halide and mercury vapor) or when they continually shut off and re-strike while the power is still on. The pulse-start metal halide (PSMH) is a high- efficiency (usually 60 to 80 lm/W) metal halide lamp and fixture. Metal halide lamps are avail- able in pulse-start and a standard version. The pulse-start system can extend lamp life by half over the standard metal halide lamp and provide about eight percent more lumens per watt than a standard HID. (Sanford, 2004) Pulse-start metal halide lamps use a different type of bal- last and are not interchangeable with standard metal halide lamps. PSMHs start, warm up, and restart faster than other HIDs. These lamps are not recommended for places where instant-on is needed because they may take one to three minutes to warm up and emit full light. When turned off, pulse-start metal halide lamps may take up to five minutes to restart because they must first cool down. The typical 175-watt mercury vapor yard light usesabout200wattswhentheballastlossesare included. This amounts to 876 kWh of electric- ityperyearor$78peryearcostat$0.085/kWh. If the MV lamp fixture is replaced with a 70-watt high pressure sodium fixture with a full cutoff reflector, the operating cost would be reduced to $39 per year. The cost of the fixture is estimated at $80–$100 for a 2.5- to 3.2-year payback. Source: Sanford, Scott. Energy-Efficient Agricultural Lighting W hen turned off, pulse-start metal halide lamps may take up to five minutes to restart because they must first cool down.
  7. 7. Page Daylighting applications where these panels may work well include shops, garages, and outbuild- ings. Panels can be integrated into existing sheet metal roofing. Energy Conserving Controls There is a variety of energy saving controls avail- able that can reduce lighting costs and increase productivity and safety. These include motion sensors, timers, photo sensors, and half-night lighting photo controllers. Motion sensors are designed to detect motion from just a few feet or up to 100 feet or more. They can be used with regular incandescent, halogen, and some CFL lamps. Most motion detectors are not designed to work with other types of high efficiency lamps. Motion sensors provide on-demand lighting for security and work areas and eliminate lighting of unoccupied areas. Check and adjust the motion sensor to avoid unintentional triggering by livestock. Timers allow you to control the exact time lamps come on and shut off. Manual timers can be pur- chased very inexpensively and often installed in existing switch boxes. Timers are especially useful for areas occupied for short periods of time, such as feed rooms, entryways, and sheds. Electronic and digital timers are more expensive and pro- vide multiple on and off points throughout the day or week. These timers are common in poul- try houses, greenhouses, and other applications where lighting is closely managed. Photo sensors are commonly used with security lights in a yard. Many photo sensors turn on at dusk and off at dawn. Sometimes, security and other lighting are not needed from early morn- ing to before dawn. Half-night sensors measure the length of every night and switch the light off halfway. Using half-night photo sensors will reduce your security light electricity bill by half. They can be purchased from most any local elec- trical supplier. For more on energy conserving controls, visit University of Wisconsin’s Biological Systems Engineering Web site at lighting_OL.html. Lighting Greenhouses Greenhouse lighting is usually designed to con- trol flowering and fruiting (called photoperiod or day length) or increase photosynthesis in lights, and spotlights. The popularity of LEDs is growing, and new lamps are available that are designed specifically for agriculture appli- cations. LEDs operate by transferring electrons between two different materials inside the lamp. In the first material, free electrons are released and move to the second material. As the elec- trons move to the second material, they give off photons. These photons are reflected using the optical components of the LED lamp. The electronics in LEDs make them suscepti- ble to moisture, heat, and dirt, all of which can cause color-shifting and shortened life. LEDs should be carefully selected if used where they will be exposed to moisture or very dirty condi- tions. LEDs are still expensive but may work well in locations where electricity costs are high, where lamps operate for long periods of time, or where a specific type of task is matched with the LED optical components. LEDs are currently being field tested in Arkansas for conventional poultry brood and feed lighting, with promising results. Daylighting Daylighting uses windows, light tubes, or sky- lights to direct sunlight inside a building. Day- lighting is well suited for work areas such as open feedlots, sheds, and other areas where work is conducted during the day. For barns, shops, and rooms with activity only during the day, a well- designed and efficient lighting system can rely on daylighting and use electric lamps as backup. South-facing windows and skylights let more winter sunlight into a work area and can reduce heating costs. Properly shading south-facing windows will let in less sunlight during the sum- mer and also help reduce cooling costs. Day- lighting can be most efficiently integrated dur- ing new construction. Light tubes are becoming a common daylight- ing method in a range of applications such as windowless rooms. Light tubes are tubular sky- lights that operate by collecting light, usually in a clear dome on the roof, and reflecting the collected sunlight through the tube to an inte- rior space. Light tubes work well in applications where windows and traditional skylights may not work well and where light is needed mostly during the day. Clear or colored roofing panels made of PVC or polycarbonate can be used for daylighting.
  8. 8. Page 8 ATTRA Energy-Efficient Lighting for the Farm that blue light wavelengths help calm birds; red wavelengths may be used to help reduce feather picking; blue-green wavelengths help maintain growth; and orange-red wavelength helps main- tain reproduction. The light intensity for layers should be enough to read a newspaper by and will vary with the poultry breed. Generally, “warm” wavelength lamps of less than 3,000K in the red-orange spectrum are best for small flocks with outdoor access. The day length should never be extended past 16 hours or the longest day of the year. Solar photovoltaic lighting provides a simple solu- tion to maintaining egg production during shorter days. Solar lighting systems basically consist of a solar module, a deep-cycle battery, a charge controller, a 12V programmable timer, and an efficient DC lighting fixture with lamp. Energy- efficient LED lamps work very well with solar modules. All of the components to build a basic low-voltage solar lighting system can be purchased online for less than $300 or as a kit. To conserve energy and keep poultry healthy, use timers to switch lights on and off. Program- mable timers must be 12V when used in con- junction with a 12V solar lighting system. There are 12V timers available online as well as sche- matics to convert a household programmable thermostat to a 12V timer. Timers also ensure that birds receive a uniform number of light hours each day. Set timers to light in the morn- ing instead of the evening to give birds a natural dusk and allow them to roost. Check timers at least once a week, and clean lamps if dust builds up. Lamps should be free of obstructions that cause shadows on the floor. plants. Photoperiod lighting is usually measured in hour or minute intervals and is adjusted for plant type. Lighting to increase photosynthetic activity is normally measured in photosynthet- ically active radiation (PAR) instead of foot- candles. PAR is defined as the number of micro- moles of photons that reach one square meter each second. Supplemental lighting to enhance photosynthesis activity is usually in the range of 40 to 80 PAR. (Fisher and Donnelly, 2001) Lighting systems for greenhouses often use a combination of high-pressure sodium vapor (HPSV) and metal halide (MH) lamps. The MH contributes light in the blue-violet range and the HPS contributes light in the yellow-orange range of the light spectrum. (Sanford, 2004) Linear flu- orescent lamps are also used in greenhouses when broad light distribution is required. Improvement of natural light transmission helps plant growth and reduces lighting costs. The type of greenhouse cover, dust on the cover, and shaded areas created by ballasts, fixtures, and other suspended objects all affect transmission of natural light. (Fisher and Donnelly, 2001) Lighting systems in greenhouses are complex. Use a professional lighting contractor to map lighting uniformity, select the best fixtures and determine fixture placement for larger projects if possible. If designing a small system your- self, purchase a light meter, start with fewer fix- tures, and add fixtures until your needs are fully met. More information on greenhouses and greenhouse lighting is available in the ATTRA publication Solar Greenhouses. Lighting for Alternative Poultry Production Supplemental lighting is normally used by alter- native egg producers to maintain productivity, and sometimes for alternative broiler production in northern climates. Small layer flocks housed during late spring through mid-summer with daily access to the outdoors do not require sup- plemental light. Supplemental lighting is neces- sary for pullets to maintain production during late fall and winter as days shorten. Poultry are very sensitive to three aspects of light: intensity of light (measured in foot- candles), wavelength (measured in color temper- ature), and day length (duration of light period). Research by Michael Darre and others has found Winter laying hens in a hoophouse. Photo courtesy of Jericho Settlers’ Farm. S upplemental lighting is necessary for pullets to maintain production during late fall and winter as days shorten.
  9. 9. Page and utility rooms. The second category includes lighting for holding areas, feeding areas, ani- mal sorting and observation and general cleanup. These areas and tasks require high to moderate light quality and quantity. Finally, low to moder- ate light quality and quantity is adequate for gen- eral lighting for livestock resting areas, passageway lighting, general room lighting and indoor and outdoor security lighting. Lamps and fixtures used in dairy lighting include fluorescent, metal halide, and high-pressure sodium. More on dairy lighting is available in the ATTRA publication Dairy Farm Energy Efficiency. Baby chicks require additional light in their first 72 hours to help them find food and water. A low watt “warm” lamp is recommended for every 200 square feet of floor space. (Hawes) The high heat from incandescent lamps may double as a brood light and heat source, although it may be more energy-efficient (and cost-effective) to use a separate heat source and a solar lighting system. More information on poultry lighting is available in the ATTRA publication Poultry House Management for Alternative Production. Dairy Lighting Appropriate lighting can improve productivity and safety on a dairy farm. On average, lighting represents 17 percent of total dairy farm electrical energy use. (Peterson, 2008) Optimal lighting con- ditions may increase milk productivity and con- serve energy. Factors that contribute to increased milk production include the type of light, the amount of light provided per watt, the tempera- ture of the work area, the height of the ceilings and the length of the lighting period. Lighting requirements on a dairy farm can be divided into three categories. The first category is visually intensive task lighting, which requires the highest light quality and quantity (Ludington et al., 2004). Areas that benefit from this type of lighting include milking parlors; equipment wash- ing, equipment maintenance and repair areas; offices; maternity and veterinary treatment areas; Lighting may be a significant portion of dairy energy costs. Photo by Andy Pressman. The basic outline of a DC solar lighting system for small alternative poultry production. Do-it-yourself solar lighting systems can be installed in movable poultry housing in the South for about $300 for a two 2-watt LED lamp system or $1,300 for five 23-watt lamps in larger, permanent houses in northern states with fewer sun hours. Lighting Disposal Most lamps should never be thrown in the trash or disposed of in burn barrels. Use recycling programs – especially for fluorescent, mercury vapor, metal halide, and other HID lamps that may contain mercury and other hazards. Lamp recycling cen- ters can be found by zip code at Summary Conserving energy with lighting may involve simple solutions like switching lights off, install- ing a timer, or replacing incandescent lamps with compact fluorescents, replacing T-12 flourescent lamps with more efficient T-8 fluo- rescent lamps, or upgrading to induction, LED, or daylighting. Efficient lamps and controls can save money in many farm applications. The ini- tial investment should be compared to the cost savings, and lighting improvements should fully meet the farm’s lighting needs. Some farms will require consultation with a professional, but many other projects can be “do-it-yourself.” Use the tools in the Resources section to help you choose the correct lighting option for your farm. 10 - 300 Watts Charge Controller Battery Bank 25-3500 Watt Hrs. Fuse Two to Five 2 - 23 Watt Lamps 12 Volt Timer
  10. 10. Page 10 ATTRA Energy-Efficient Lighting for the Farm Table 2: Lamp comparison. Adapted from ASABE, ASAE EP344.3; Sanford, 2004; Auburn University, University of Arkansas, U.S. Department of Energy and manufacturer literature. Lamp Type Lumens/ watt Average Rated Life(hrs)* Color CRI CCT (K) Instant On (min.) Ballast Minimum Start Temp. (o F)** Application Standard Incandescent 5 – 30 750 – 4,000 White 98 – 100 2,700 – 2,850 Yes No Below 0 Indoor/outdoor Tungsten Halogen 12 – 25 2,000 – 6,000 White 98 – 100 2,750 – 3,200 Yes No Below 0 Indoor/outdoor Compact Fluorescent 50 – 80 6,000 – 12,000 White 65 – 95 2,700 – 6,500 Yes but warms up to full output Yes 50 Indoor/outdoor, poultry houses, storage room and general lighting Cold Cathode Compact Fluorescent 41 – 49 18,000 – 25,000 Bluish to White 82 – 84 2,200 – 4,500 Yes Internal -10 Indoor/outdoor, poultry, and general lighting T-12 Fluorescent 75 – 98 6,500 – 20,000 White 52 – 95 3,000 – 6,500 Yes Yes 50 Indoor, milking parlor, milk room, storage rooms and bay areas T-12 High Out- put Fluorescent 75 – 98 6,500 – 20,000 White 70 – 95 4,100 – 6,500 Yes Yes -20 Indoor, milking parlor, milk room, storage rooms and bay areas T-8 Fluorescent 75 – 98 7,500 – 20,000 White 52 – 95 3,000 – 5,000 Yes Yes 0 General area lighting of all kinds and low bay areas T-8 High Output Fluorescent 75 – 98 6,500 – 20,000 White 70 – 95 3,500 – 4,100 Yes Yes -20 Indoor, milking parlor, milk room, storage rooms and bay areas Induction 50 – 90 60,000 – 100,000 White 80 – 90 2,700 – 6,500 Yes Yes -40 Where maintenance costs are high Quartz Pulse- Start Metal Halide 60 – 80 5,000 – 20,000 Bluish 65 – 75 2,900 – 4,200 No (1 – 3) Yes Below 0 Indoor/outdoor including high bay and greenhouses Ceramic Pulse- Start Metal Halide 60 – 80 20,000 Bluish 85 – 94 2,900 – 4,200 No (1 – 3) Yes Below 0 Indoor/outdoor including high bay and greenhouses High- Pressure Sodium Vapor 50 – 140 15,000 – 24,000 Yellow- Orange 20 – 80 1,900 – 2,200 No (3 – 5) Yes Below 0 Indoor/outdoor, poultry, livestock holding areas and greenhouses Low Pressure Sodium 60 – 150 12,000 – 18,000 Yellow -44 1,700 – 1,800 No (7 – 15) Yes Below 0 Indoor/outdoor, general and security Mercury Vapor 25 – 60 16,000 – 24,000 Bluish 50 3,200 – 7,000 No (1 – 15) Yes Outdoor Light Emitting Diode 4 – 150 35,000 – 50,000 White 80 – 90 2,700 – 10,000 Yes “Driver” NA Indoor/outdoor where color identifi- cation is important All data and information are based upon a survey of literature and do not necessarily represent all available lamps. *Average rated life may vary depending on the lamp being switched on and off and the operating environment. ** Minimum start temperatures may vary depending on the lamp and ballast combination.
  11. 11. Page References American Society of Agricultural and Biological Engineers (ASABE). Lighting Systems for Agricultural Facilities. Standard EP344.3. January 2005. Darre, Michael. Light and Lighting for Poultry. University of Connecticut. Last accessed February 2010. Fisher, Paul and Caroline Donnelly. Evaluating Supplemen- tal Light for Your Greenhouse. Department of Horticulture, Clemson University. May 2001. Last accessed April 2010. Hawes, Robert. Lighting for Small-Scale Flocks. University of Main Cooperative Extension. Maine Poultry Facts. Bulletin #2227. Last accessed February 2010. Hiatt, Richard. 2008. Agricultural Lighting. Presentation at the Farm Energy Audit Training for Field Advisors workshop. Augusta, ME. January. Lighting Guides. Last accessed April 2010. Ludington, David, Eric Johnson, James Kowalski, Anne Magem and Richard Peterson. 2004. Dairy Farm Energy Efficiency Guide. Ithaca, NY: DLTech, Inc. Natural Resources Conservation Service. Energy Self Assessment. default_lighting.aspx Peterson, Richard. 2008. Energy Management for Dairy Farms. Presentation at the Farm Energy Audit Training for Field Advisors workshop. Augusta, ME. January. Sanford, Scott. 2004. Energy Conservation in Agriculture: Energy Efficiency Agricultural Lighting. University of Wisconsin - Cooperative Extension Publication (A3784-14). Madison, Wisconsin: University of Wisconsin. Tabler, Tom. 2009. Energy-Efficient Lighting. Presentation at the Southeast Asian American Farmers Association meeting. Clarksville, Arkansas. October. U.S. Energy Information Administration. Voluntary Reporting of Greenhouse Gases Program. Last accessed April 2010. U.S. Department of Energy. Energy Savers. Last accessed April 2010. daylighting/index.cfm/mytopic=11980 U.S. Department of Energy. EnergySTAR. Lighting. 2006. Last access June 2010. cfm?c=business.EPA_BUM_CH6_Lighting Resources Equipment Suppliers FarmTek 1440 Field of Dreams Way Dyersville, IA 52040 Toll-free: 1-800-327-6835 Sells many types of lamps and lighting equipment for poultry, greenhouses and the farm. Real Goods Solar, Inc. 833 W. South Boulder Rd. Louisville, CO 80027 Toll-free: 1-800-919-2400 Sells many types of solar lighting components and kits. Backwoods Solar 1589 Rapid Lightning Creek Rd. Sandpoint, ID 83864 Phone: 208-263-4290 Sells 12-volt DC timers and other solar lighting components for do-it-yourself solar poultry lighting. Rooster Booster Poultry Lighting Selmech Supplies Ltd 19 Norton Enterprise Park Churchfields Salisbury Wiltshire SP2 7YS Phone: 01722 413440 Sells lighting equipment for poultry. ACF Greenhouses 380 Greenhouse Drive Buffalo Junction, VA 24529 Toll-free: 1-888-888-9050 Provides resources on greenhouse lighting design and sells equipment for do-it-yourself projects. EnviroCept Greenhouses & Supply P.O. BOX 914 Benton City, WA 99320 Toll-free: 1-888-326-8634 Sells greenhouse lighting equipment for large commercial and do-it-yourself projects. Visit ATTRA’s Directory of Energy Alternatives (www. for a state-by-state directory of alternative
  12. 12. Page 12 ATTRA Energy-Efficient Lighting for the Farm By Leif Kindberg NCAT Farm Energy Specialist © 2010 NCAT Holly Michels, Editor Amy Smith, Production This publication is available on the Web at: or IP369 Slot 368 Version 083110 EnergySTAR Provides guidance on selecting energy-efficient lamps and fixtures. EnergySTAR Lighting CH6_Lighting Discusses lighting application considerations and general lighting. EnSave This commercial site offers technical papers on efficient lighting and other farm energy topics. Rural Electricity Resource Council National clearinghouse and technical support provider on energy efficiency with an emphasis on rural applications. Wisconsin’s Focus on Energy Wisconsin-based program providing information, resources and financial incentives to help implement energy-efficient and renewable energy projects. Agricultural and Rural Business Programs provides information on energy efficiency for agricultural producers. Biological Systems Engineering A University of Wisconsin – Madison resource that provides guidance on lighting and other farm energy topics. energy installers and consultants, or call ATTRA at 1-800-346-9140. Tools and Websites Lighting Self Assessment Tool lighting.aspx The Lighting Energy Self Assessment Tool available from the USDA Natural Resources Conservation Service is designed to estimate your current lighting energy use based on your inputs and to suggest more efficient alternatives. Energy Savers – Lighting and Daylighting cfm/mytopic=11970 The Department of Energy (DOE) Energy Savers website provides information and resources on energy- efficient lighting and daylighting. This commercial site provides a large list of lighting design formulas and other useful lighting tools. Center for Ecological Technology Organization provides publications and links on energy- efficient and renewable energy technologies.