Online solar power calculators and resources help homeowners with questions like “Will solar power work for my home?” and “What financial options are available?” Solar companies will often provide free estimates.
Solar photovoltaics require sunlight which varies due to geographical location, climate, home orientation, roof slope, season, time of day, shade, and cloud cover.
The cost of a PV system depends on the design, equipment (panels, inverters, batteries, etc.), labor, and permits, less any rebates or incentives. Keep in mind the environmental benefits are not reflected in the cost. Some financial options include:
A customer makes a capital investment up front and owns the PV system. After the payback period, which is how long it takes the PV system to produce enough electricity to pay back the original investment, generating electricity is virtually free.
A third party owns and operates a PV system on a customer’s property and the customer pays for the use of it. At the end of the lease, the customer may be given an option to purchase the PV system, extend the lease, or have the equipment removed.
A third party owns and operates a PV system on a customer’s property and sells the electricity generated to the customer at lower than local utility rates.
PROPERTY-ASSESSED CLEAN ENERGY
A local government pays for a PV system and the homeowner repays the loan through property taxes.
SOLAR RENEWABLE ENERGY CERTIFICATE LOAN
A utility company pays for a portion of a PV system and is repaid by the customer.
REBATES AND INCENTIVES
Many utilities offer rebates to customers who install renewable energy generating systems. Incentives are often available from local, state, and federal government agencies.
Grid-tie vs. Off-grid
Solar panels do not store excess electricity generated during the day and when the sun goes down or on exceptionally cloudy days, solar panels do not generate electricity. In order to ensure electricity is available 24 / 7 a PV system either needs have batteries or be connected to the utility grid.
Many PV systems are grid-tied. During the day, excess electricity generated by a customer PV system is “sold” to the local utility and at night the customer “buys” electricity back from the utility.
Battery storage adds to the cost of a PV system but enables homeowners to be self sufficient, which is especially useful if the utility grid goes down. Excess electricity generated during the day is stored in the batteries and accessed at night.
Major components of a PV system are solar panels, power inverters, plus batteries and charge controllers for stand-alone systems. Equipment selection factors include: solar panel efficiency (how much sunlight is converted to electricity), life expectancy, warranty, embodied energy (energy required to produce the equipment), where equipment is made, and cost.
Although it may be possible to design and install a home rooftop PV system oneself, many homeowners will want and need to work with professionals. There are companies that design, sell, or install PV systems, and those that do it all.
Be prepared to share your goals, past electricity usage, future electricity requirements, and expectations. This will enable the company you select to provide a quote for equipment and services that meet your needs and eliminate surprises down the road.
To find a qualified company, ask someone you know who has a PV system for a referral, search government agency databases, or check industry association websites.
- Consider interviewing several companies.
- Ask for and check references.
- Make sure the installer has a valid contractor license, workers compensation insurance for employees, and liability insurance.
- Ask questions to ensure you understand what you are getting (equipment, services, warranty, etc).
- Get everything in writing.
A complete rooftop solar quote will include evaluating a home’s suitability for PV power generation, designing the system, drawings, permit, equipment, materials, installation, warranty, facilitating grid connection (if applicable), applying for rebates on behalf of the customer, and providing tax incentive information.
- American Solar Energy Society
- CA Contractors State License Board
- Database of State Incentives for Renewable & Efficiency (DSIRE)
- Go Solar California
- National Energy Renewable Laboratory – Solar Photovoltaic Technology Basics
- Solar Energy Industries Association (SEIA)
- U.S. DOE – Own Your Power! A Consumer Guide to Solar Electricity for the Home
- U.S. DOE – Small Solar Electric Systems
- Wikipedia – Photovoltaic System