Dairy Farm Energy Management Handbook - Wisconsin Department ...

Equipment Operation and Maintenance
Lighting Efficiently
As was mentioned earlier, lighting can account
from 15% up to about 24% of electricity costs on
a dairy farm. Learning how to use lighting
effectively and efficiently not only can help trim
your utility costs, but it can also improve working
conditions and cow comfort.
In a dairy, you are basically looking at three
major characteristics in lighting-system
performance:
Recommended Illumination Levels for Dairy
Facility Chart
• Light intensity or illumination level:
Illumination levels are measured with a
light meter and expressed in foot-candles
(fc).
In a free-stall, for example, a typical and
recommended illumination level would be
an average of 15 fc, while a holding area
can usually get by with 10 fc. As
Working conditions and cow comfort,
as well as conserving energy, are
greatly improved when lighting fixtures
are used effectively and efficiently. --
Photo Karl Ohm
reference, a well-lit office usually has a light intensity of 35 to 50 foot
candles.
To help enhance a light’s illumination, especially in outdoor yard lights,
Sanford recommends retrofitting the light with a simple, snap-on full
reflector that replaces the standard refractor.
A refractor, which is a prism-type glass, only directs about 30% of the
full lighting to where it’s really needed.
Color characteristics: Just like sunlight with its various wavelengths that
produce the different colors of a rainbow, artificial lights also produce their
own distinct color spectrum that influence how well objects can be perceived
by the human eye.
A commonly used rating is the Color Rendition Index (CRI), which ranges
from 0 to 100 and indicates the light’s ability to render the true color of an
object. Lights with higher CRI values produce light that renders a truer color,
while lower CRI values produce some color distortion.