How Well Does It Work?
Lab Results Tell the Story
Here’s where to find independent testing reports on solar energy products.
By Charlie angelo
the renewaBle enerGY inDustrY
is growing fast, with new and improved products arriving in the market every month. Performance claims for photovoltaic (PV) modules and water-heating systems vary widely. in
order to know whether the equipment you’re
buying will really do the job, it would be helpful
to have access to standardized testing results.
happily, state and federal agencies feel the
same way. in many states, the law says you can’t
receive tax credits or other reimbursement for
a new solar installation unless the equipment
is on an approved list of tested and validated
products. The laboratory test results are published on several websites, and these are great
sources of information on the efficiency and
value of solar power products.
Water-Heating and Geothermal
Systems test results
a primary source for consumer reports on
solar heating equipment is the solar rating
and Certification Corp. (srCC, at solar-rat-
ing.org), a nonprofit organization founded in
1980 to certify the performance of solar energy
equipment. testing is done by independent
laboratories that are accredited by srCC.
Click on the “Collector ratings summaries”
and “system ratings summaries” links at solar-
rating.org/ratings/ratings.htm. a list of labora-
tories that test for srCC can be found at solar-
The FseC also tests solar water-heating sys-
tems. see their certification list at fsec.ucf.edu/
another great source on solar water-heating
products is energy star, the joint program of the
u.s. environmental Protection agency and the
u.s. Department of energy. at energy star.gov,
consumers can find performance reports on
solar water heaters and geothermal heat pumps.
system specifications and warranty information
are given for each product reviewed.
The energy star database now lists more
than 100 solar water-heater models from 11
different brands. access the energy star site at
energy star also offers a database of more
than 500 different types of geothermal heat
pumps. see tinyurl.com/2ryzre. GS
voltaics ( pvgap.org) lists certified solar equipment and has a list of solar equipment testing
facilities around the world. The organization
approves products according to the standards
published by the international electrotechnical Commission.
The Florida solar energy Center (FseC) was
established by the Florida legislature in 1975.
it tests and certifies equipment and reports the
results at fsec.ucf.edu/en/industry testing.
Photovoltaic test results
California has a database of certified solar
equipment at gosolarcalifornia.org that’s a
great resource no matter where you live. The
certification is based on the state’s recently
implemented senate Bill 1 guidelines. in order
to be eligible for taxpayer-funded incentives in
California, an energy project has to use equipment meeting these standards.
Go solar California’s ratings are calculated
using the PVusa test Conditions protocol.
each module is exposed to light at a standard
irradiance of 1,000 watts per square meter, at
an air temperature of 20°C ( 68°F) and wind
speed of 1 meter per second ( 22 mph), all at
10 meters ( 33 feet) above ground level. This
gives a valid comparison between panels tested
under the same protocol, but it doesn’t really
predict real-world performance on your roof.
For that, you need to take into account the
actual temperature on the roof, the precise
angle of the panel relative to the sun throughout the day, shading issues and the efficiency of
the wiring and inverter. a good site for estimating the output of a proposed PV system is PV
watts ( nrel.gov/rredc/pvwatts).
Go solar California also provides links to
consumer reports for inverters, system moni-
toring meters and various other gear.
The Global approval Program for Photo-
Charlie angelo is SOLAR TODAY’s intern. He holds a
bachelor’s degree in journalism from the University
of Colorado at Boulder. ( firstname.lastname@example.org)