NEXT STEPS working with an installer >>
Patrick armentrout and Jason houston of namaste Solar install a 9.9-k W SunPower solar photovol-
taic system in Boulder, Colo.
How to Work
systems, they can also be used when looking
for a solar thermal installer.
Solar is an investment for
the long term. Your solar
installer should be someone
you can rely on.
By Dan YeChout
solar Power is a Major investment
that needs to be tailored to your house and
your lifestyle. Designing the system is a complex process best tackled in detailed discussions with a knowledgeable installer. Moreover, it’s a long-term investment. Because the
array may produce power for at least 30 years,
you’ll want to establish a solid relationship with
your installer. Follow these tips when searching
for a system installer. Though these guidelines
deal primarily with installers ofsolar electric
Designing Your System
Your installer can help you figure out the
optimum size for your system. it will depend
on the rate at which you use electricity, your
budget, the size and shape of your roof and the
incentives offered by your state and utility. For
instance, in some areas, incentives won’t cover
systems of more than 2 kilowatts.
Begin the design process with a review of
the electricity usage history for the home. if
past bills are not on file, get an account history from your utility company. Consider
whether lifestyle changes will affect your utility bills in the future. are you adding a kid to
the household or sending one off to college?
setting up a home office? if you plan to add air
conditioning, an electric car or more people to
the household, estimate the additional future
You’ll need to understand the electric rate
structure of your local utility. Your utility
company may bill and pay for straight kilowatt-hour (kwh) rates, inverse-tiered rates
or time-of-use rates.
where straight kwh net-meter rates are
offered, the utility company typically buys all
your solar-power generation at the same retail
rate, up to 100 percent of your consumption.
in these cases, you can size your photovoltaic
(PV) system to cover up to 100 percent of your
expected energy use. Beyond 100 percent, the
utility company often buys the surplus at a
lower wholesale rate. Because PV systems tend
to be less expensive per watt as they grow larg-
er, the optimum investment in a straight-kwh
rate structure is often to generate just under
100 percent of your consumption. some utili-
ties may offer a feed-in tariff, where the solar
production is metered separately and the pur-
chase rate is not related to your consumption.
under an inverse-tier rate structure, the util-
ity company charges more for higher amounts
of usage, similar to a tax bracket structure. For
example, the utility may charge a base rate for
usage under 300 kwh per month, a higher rate
for the next 200 kwh, and so on. under an
inverse-tier structure, the PV system can help
you stay in lower-tier rates. Your best invest-
ment may be to size the PV system to get you
into the low-tier rates but not necessarily cover
100 percent of your usage.
in time-of-use structures, the utility com-
pany charges more for electricity during peak
consumption periods. Peak consumption typi-
cally occurs in the afternoon when people are
working and running air conditioners. under a
time-of-use structure, PV panels that face more
southwesterly will generate electricity when
electricity is most expensive.
Finally, estimate the remaining life of your
roof. Your PV system should be in place for at
least 20 years, so you want to make sure your
roof has that much life left as well. otherwise,
you will be facing an additional expense to
remove and reinstall the PV system when it is
time to reroof.
an experienced local installer will already
have done the appropriate calculations for
other customers and can walk you quickly
through this exercise.
researching Solar Installers
Get proposals from three different companies and see how each handles the design process. Personal referrals are your best source