Indoor Lighting

Indoor lighting in agricultural enterprises would include tie stalls barns, parlors, freestall barns, poultry housing, swine housing, greenhouses, shops and outbuildings. Some of these areas are cold during part of the year which can affect the types of lighting used.


In tie stall barns, milk rooms, milking parlors and feed rooms, a standard T-8 or T-5 fluorescent lamp or LED in a damp-environment rated fixture (lens with a gasket) should be used. If the feed room or utility room could get below 0°F then a high-output T-8 or T-5 lamp or LED bulb in a damp-rated fixture must be used. In a freestall barn with rafters or trusses 12 feet or higher, pulse-start metal halide (PSMH) lamps or the more efficient high pressure sodium  (HPS) or LED lamps are the best choice to used. They can also be used in a low bay type fixture with a wide distribution diffuser. In barns with low side walls (8 to 12 feet high), high-output T-8 or T-5 lamps or LED lamp in a damp rated fixture work best. T-5 or T-8 fluorescent lamps can also be used in freestall barns but will have higher maintenance costs than LED lamps.  In the typical 32 to 36 foot wide tie stall barn, a continuous row of 2-lamp fluorescent or LED fixtures down the center alley and a 2-lamp, 4-foot fixture every 8 feet or continuous row of single lamp fixtures in the feed alley will provide approximately 15 to 20 foot-candles of light, enough for long day lighting and general chores. Lights used for long day lighting should be controlled by time clocks to ensure consistent on and off times. Refer to the Dairy Section of this web site for more information on “Long day lighting for dairy cows”.


Typical poultry housing uses incandescent lamps for lighting. If light manipulation is required, the incandescent bulbs are usually controlled with a dimmer control. Incandescent bulbs are the least efficient and could be replaced with compact fluorescent lamps (CFL) which are 75% more efficient. Another option is T-8 fluorescent fixtures which are six to ten times more energy-efficient than incandescent lighting. All lighting fixtures for poultry buildings should be water-resistant rated due to higher humidity levels of animal housing.

If light level manipulation is required, such as for raising pullets, there are a few options:

  • Use dimmable compact fluorescent lamps and a standard dimmer control. Dimmable CFLs are new and available in a limited number of wattages. The dimmable CFLs are not readily available and may have to be ordered from your local supplier. The CFLs should be housed in an enclosed fixture such as a jelly jar to protect it from moisture. The lamp must be rated for an enclosed fixture; otherwise it will likely overheat and cycle on and off. CFLs can be dimmed to about 20% of maximum luminous output.
  • Use new dimmable T-8 Fluorescent lamps and ballasts. This requires a special ballast but uses standard lamps. There are two types of dimmable T-8 ballasts available: continuous dimming that can be varied with a sliding dimmer between 100 and 5% of light output and a switching dimmer which has preset levels of light reduction (100% & 50% or 100%/ 60%/ 30%). The switching dimmer requires two switches but has the advantage of being able to switch between different light levels automatically. This may be cost effective lighting because of the higher lamp efficiency versus incandescent bulbs (about 15 lumens/watt versus 85 lumens per watt for fluorescent lamps) and longer lamp life (20,000 hours for fluorescent lamps versus 750 to 1000 hours) despite the higher initial cost.. The one downside of dimmable ballasts is that the new lamps need to operate at full output for 100 hours before dimming; otherwise lamp life will be shortened
  • LED lamps can be used but are new. Lamps need to be proven in the poultry barn environment. The following is an article with a summary about adopting LED lamps


Providing supplemental lighting for plant growth can decrease growing times and reduce the risk associated with low sunlight level. Plant growth is directly related to the amount of light energy received on the leaf surfaces. Plants have a saturation level for the amount of light energy they can absorb; above this level, additional light energy will not increase plant growth. The saturation level does vary with plant species. Refer to the Greenhouse section of this website for more information – Click Here

Other Animal Housing

For any animal housing the lighting fixtures should be sealed against moisture and dust. This improves safety, lowers maintenance and aids in getting long life from the fixtures and lamps. If the housing is cold, less than 0°F, at any time of the year, then T-8 fluorescent lamps with high-output ballasts will be needed or pulse-start metal-halide or high pressure sodium high intensity discharge lights can be used if the ceilings or rafters are 12 feet or higher. If only lighting a small area, it may be more cost effective to use compact fluorescent lamps in sealed fixtures.

Non-Animal Housing

Open fixtures can be used in many non-animal areas such as farm shops, office space, dry utility rooms and machinery storage buildings. In feed rooms or dusty areas, sealed dust-resistant fixtures should be used. In areas where flies are numerous, sealed fixtures have an advantage even though they may not be required, with respect to maintenance because they can be easily cleaned with a power sprayer or cleanser and rag versus having to removed and cleaned lamps individually. T-8 fluorescent lamps are preferred in most applications however if ceiling are greater that 12 feet high, MH or HPS fixtures may be more cost effective.


If you have questions about the information on this site, please contact
Scott Sanford, Distinguished Outreach Specialist, University of Wisconsin,