Retrotec USACE - Manual (Page 224)

D94 ENERGY & PROCESS ASSESSMENT PROTOCOL
and high-effi ciency electronic ballasts (when replacing installations earlier
than 2002) provide added effi ciencies of 15% or greater. In many cases, this
15% gain can be cost-effective for lighting retrofi ts and should defi nitely be in-
stalled in all new construction. New high-performance T8 lamps have a higher
color rendering index (CRI) than the commodity-grade fl uorescent T8 lamps
commonly used. Higher CRI leads to better lighting quality. In addition, these
lamps have a longer lamp life and higher lumen maintenance, resulting in low-
ered operating costs and less light loss as lamps age. The direct consequences of
higher lumen maintenance are that lighting designs can be implemented with
lower initial wattages, since the lighting designer does not have to “overdesign”
the system to compensate for eventual light loss.
Higher-effi ciency (premium) ballasts (Figure D149) provide 8–10% energy
savings. If the system was installed around 10 years ago, it is cost-effective to
change out the ballasts to the new ones for energy savings—the old ones are
due for replacement anyway and will start failing in larger numbers after about
15 years in service. The combination of high-performance T8 lamps and pre-
mium ballasts is most easily accomplished by changing out old normal ballast
factor ballasts with premium low ballast factor ballasts and changing the lamps
to high-performance T8 lamps.
New lamp wattages are now available. Although 30 W, 28 W, and 25 W
versions of T8 lamps can be used, be sure to use ballasts that are specifi cally
designed for these lamps—do not change to lower-wattage lamps without also
changing the ballasts to ensure proper operation of the lamps and optimizing
for energy savings.
D.5.9 Using Older Technologies Such as T12 Fluorescent Lamps
with Magnetic Ballasts (Ineffi ciency)
T12 fl uorescent lamps and magnetic ballasts are old technology—the lighting
equivalent of driving a car from the 1960s. Newer equipment is not only avail-
able, it is proven technology and has such signifi cant market penetration that
it can no longer be considered cutting-edge. T8s and electronic ballasts should
be used to replace T12s and magnetic ballasts for improved effi ciency (50%).
T8 lamps are also smaller, and their electronic ballasts are lighter-weight,
making the T8 system an easy replacement as well as a better design for newer
fi xtures.
Identifying T12 lamps is easy—measure the diameter of the fl uorescent
bulb; if it is 1½ in in diameter, it is a dinosaur, a T12 lamp. Some installations
of T12 lamps use electronic ballasts, but even these systems are not as energy-
effi cient as T8 systems. It is best to use the most current (“extra-effi cient,”
or “third-generation”) T8 lamps extra-effi cient or premium electronic ballasts.
These T8 systems are the most energy-effi cient lighting systems available for
commercial buildings.