Energy-Efficient Lighting for the Farm

1. The National Sustainable
Agriculture Information Service,
ATTRA (www.attra.ncat.org),
was developed and is managed
by the National Center for
Appropriate Technology (NCAT).
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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. 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
www.attra.ncat.org 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. Page 3ATTRAwww.attra.ncat.org
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. 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 http://ruralenergy.wisc.edu/
conservation/default.aspx for lighting to help
you choose energy-efficient lighting.

5. Page 5ATTRAwww.attra.ncat.org
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. 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. Page 7ATTRAwww.attra.ncat.org
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 www.uwex.edu/energy/
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. 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. Page 9ATTRAwww.attra.ncat.org
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 www.earth911.org.
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. 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. Page 11ATTRAwww.attra.ncat.org
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.
www.sp.uconn.edu/~mdarre/poultrypages/light_inset.html
Fisher, Paul and Caroline Donnelly. Evaluating Supplemen-
tal Light for Your Greenhouse. Department of Horticulture,
Clemson University. May 2001. Last accessed April 2010.
http://extension.unh.edu/Agric/AGGHFL/OFAlight.pdf
Hawes, Robert. Lighting for Small-Scale Flocks. University
of Main Cooperative Extension. Maine Poultry Facts.
Bulletin #2227. Last accessed February 2010.
www.umext.maine.edu/onlinepubs/htmpubs/2227.htm
Hiatt, Richard. 2008. Agricultural Lighting. Presentation
at the Farm Energy Audit Training for Field Advisors
workshop. Augusta, ME. January.
Lightsearch.com. Lighting Guides. Last accessed April
2010. www.lightsearch.com/resources/lightguides
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. http://ruralenergy.wisc.edu/conservation/lighting/
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. www.eia.doe.gov/oiaf/1605/ee-factors.html
U.S. Department of Energy. Energy Savers. Last accessed
April 2010. www.energysavers.gov/your_home/lighting_
daylighting/index.cfm/mytopic=11980
U.S. Department of Energy. EnergySTAR. Lighting.
2006. Last access June 2010. www.energystar.gov/index.
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
www.farmtek.com
www.growerssupply.com
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
www.realgoods.com
Sells many types of solar lighting components and kits.
Backwoods Solar
1589 Rapid Lightning Creek Rd.
Sandpoint, ID 83864
Phone: 208-263-4290
www.backwoodssolar.com
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
www.roosterbooster.co.uk
Sells lighting equipment for poultry.
ACF Greenhouses
380 Greenhouse Drive
Buffalo Junction, VA 24529
Toll-free: 1-888-888-9050
www.littlegreenhouse.com
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
www.greenhouses-etc.net/lighting
Sells greenhouse lighting equipment for large commercial and
do-it-yourself projects.
Visit ATTRA’s Directory of Energy Alternatives (www.
attra.ncat.org/dea) for a state-by-state directory of alternative

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:
www.attra.ncat.org/attra-pub/farmlighting.html
or
www.attra.ncat.org/attra-pub/PDF/farmlighting.pdf
IP369
Slot 368
Version 083110
EnergySTAR
www.energystar.gov/index.cfm?c=products.pr_find_es_products
Provides guidance on selecting energy-efficient lamps
and fixtures.
EnergySTAR Lighting
www.energystar.gov/index.cfm?c=business.EPA_BUM_
CH6_Lighting
Discusses lighting application considerations and
general lighting.
EnSave
www.ensave.com
This commercial site offers technical papers on efficient
lighting and other farm energy topics.
Rural Electricity Resource Council
www.rerc.org
National clearinghouse and technical support provider on
energy efficiency with an emphasis on rural applications.
Wisconsin’s Focus on Energy
www.focusonenergy.com
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
www.uwex.edu/energy/AgEnergy.html
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
http://ruralenergy.wisc.edu/conservation/lighting/default_
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
www.energysavers.gov/your_home/lighting_daylighting/index.
cfm/mytopic=11970
The Department of Energy (DOE) Energy Savers
website provides information and resources on energy-
efficient lighting and daylighting.
Lightsearch.com
www.lightsearch.com/resources/lightguides
This commercial site provides a large list of lighting design
formulas and other useful lighting tools.
Center for Ecological Technology
www.cetonline.org
Organization provides publications and links on energy-
efficient and renewable energy technologies.