Qualifications for a solar
energy system to be one of our nations Million Solar
To be included in the Million Solar Roofs Initiative, a
building's solar energy system must comply with all relevant
parts of the National Electrical Code (NEC), Underwriters
Laboratories (UL) standards, and the Solar Rating and
Certification Corporation (SRCC) standards. The system must
also be located on or immediately adjacent to the building
and meet the following minimum standards.
Residential systems must be a minimum of 0.5 kW.
School and church systems must be a minimum of 1.0
Commercial systems must be a minimum of 2.0 kW.
Solar Thermal Water Heating Systems:
Residential domestic systems must be a minimum of 1.0 kW
equivalent or 20 square feet of collector area.
Residential swimming pool heating systems must be a minimum
of 100 square feet of collector area.
Commercial domestic systems must be a minimum of 2.0 kW or
40 square feet of collector area.
Commercial swimming pool heating systems must be a minimum
of 400 square feet of collector area.
Solar Thermal Space Heating Systems:
Collector area must be a minimum of 100 square feet or 4.0
Cost of Solar Energy Systems
A residential solar hot water system may cost anywhere from
$1,800 to $3,500 and compete effectively with water heated
by electricity that costs 8 cents per kWh or more. Solar
thermal space heating is very effective in most areas of the
country. For example, the cost of a 100-square-foot
transpired collector installation can range from $1,000 for
retrofits on existing buildings and $500-$700 for new
systems, but can produce energy savings to offset the entire
cost of the system in five years or less.
Photovoltaic costs are more complicated because system size,
features, and net cost to the users depend on the financing
terms and interest rates, available incentives, and access
to low-cost hardware and installation through bulk
purchasing programs. For example, in a recent
of Million Solar Roof photovoltaic system costs from 1997 to
2000 found that residential photovoltaic systems installed
in Sacramento, California, cost about $5,100 per kilowatt
(this cost does not include the incentives available which
lower the cost to the homeowner significantly) and provide
energy at approximately 18 cents per kilowatt-hour
?primarily due to a forward looking bulk purchase agreement
with a manufacturer. This same study found the national
average cost of a grid-tied photovoltaic system to be $7,400
per kilowatt and off-grid systems (which include battery
back-up in order to have electricity when the sun isn°
shining) cost about $14,000 per kilowatt.
Did you install a system that