Solar System FAQ


A solar electric system (or photovoltaic system) uses solar panels to convert sunlight to electricity. The panels produce direct-current (DC) electricity, but this must be converted to alternating-current (AC) power which is the type used in your home. An inverter (or sometimes multiple microinverters) are used you can use to supply a part of the electricity you use. When you produce more electricity than you use at any given time, in most cases you can put that electricity back onto the power grid and receive credits from your utility for the power you provide.

A home with a south-facing roof and little or no shade is ideal. Shaded roofs and east- and west-facing roofs also are viable, but have a lower annual output. A qualified solar installer can perform an analysis of your roof and suggest your best options.

No. Having solar on your roof does not generally mean you are “off the grid”. Almost all solar systems are “grid-tied” systems, allowing a homeowner to use the electrical grid as a “battery”. For example, you can put excess electricity onto the grid during the day and draw power back from the grid at night. While it is possible to design a system that enables your home to be off the grid, this is not common. To effectively go off grid, a home would require a large bank of batteries, which would add substantially to the cost of a system.

If your solar panel system is connected to the grid and you don’t have battery storage, your system will shut off in the event of a blackout. This is to prevent emergency responders and electricity utility personnel from being injured by solar panels sending power back to the grid. However, certain types of inverters can provide backup power in a blackout as long as the sun is shining.

When you install solar panels on your property, you will very likely still be connected to the grid. This allows you to draw from the grid when your system is not producing all of the power that you need, and send power back to the grid when you produce more than you use. It is possible to go off the grid with a solar energy system that includes battery storage, but it will cost significantly more and is unnecessary for the majority of homeowners.

At night and on very cloudy days, a solar system goes dormant. During these times you will get power from the grid.

Current mounting systems are very resistant to leaks. Ask your solar installer how your system will be mounted and how any roof penetrations will be sealed.

Solar manufacturers have created mounting methods and equipment for most commonly used roofing materials. Some types of roofing materials (such as composition shingles) are easier to install solar on and others (such as clay tiles or wood shingles) present more of a challenge.

Yes, some solar installers offer this service, but it is generally more costly and complex.

Some solar installers will provide very small systems (even under 1 kW). However, many installers will only consider installations above a certain capacity (such as 2 kW). In general, smaller system have a lower overall cost but a higher per-kW cost.

Solar electric systems almost always stay with the home on which they are initially installed. The cost to remove and reinstall a system on a different home is very high. Solar homes normally have a higher resale value since they have lower monthly energy costs.

Generally no. The solar technology almost always used to heat a pool is called solar thermal heating. This is a different technology than the phototovoltaic technology used to convert sunlight into electricity.

Two key solar technologies are available for domestic water heating. Solar thermal (not solar electric) heating involves running a fluid through a particular type of solar panel. This is a more-direct way to use solar for water heating, but is generally expensive and prone to leakage and other maintenance problems. The other approach, which is generally consdered to be cheaper and more reliable, involves producing electricity in solar electric panels and then using this electricity for water heating. To heat the water electrically, you can use a highly efficient heat pump water heater (HPWH) or a conventional electric water heater.


System prices vary by size and technology. A typical roof-mounted system normally ranges between $2.25 to $5.00 per Watt. For a 4kW solar system, typical costs range between $9,000 to $14,000 before any tax credits. Smaller systems generally cost more per Watt.

This varies greatly based on whether you purchase the system, take out a loan, or use a Lease/PPA program. If you purchase the system, you’ll pay the cost of the system up front and also be responsible for any maintenance costs that occur after the warranty period of the components. However, you won’t have a recurring monthly cost to pay for the solar system. With a loan, you’ll pay little or nothing up front, but pay back the loan and any maintenance costs over time. With a Lease/PPA, you may pay little or nothing up front and have no responsibility for maintenance costs, but you’ll pay a recurring monthly charge. If you can afford it, the economics of the direct-purchase approach are generally the most favorable.

The most cost-effective installations are in homes with large electric bills and unshaded roof space facing generally south. However, many people with smaller bills and less-than-optimal roof orientations also find the economics of solar to be compelling. Additionally, homeowners often install solar primarily as a way to benefit the environment, rather than for economic reasons.

Studies have shown that homes with solar energy systems sell for more than homes without them. However, your property value will likely only increase if you own, rather than lease, your solar system.

It will depend on what type of solar contract you have and the age of your system. The value of your home may increase if the solar system is free of encumbrances, like a lease or a PPA. With a lease or PPA, the details would need to be worked out with your solar provider to transfer the lease or PPA obligations to the new homebuyer.

Payback time is determined by many factors, most importantly the amount of your current electricity bill and the up-front cost of your system. Customers who directly purchase the system and have large bills may see a return on their investment in as little as 3 to 5 years, while direct-purchase customers with lower bills will have a longer payback period.

Yes, a one-time fee of $145 is charged. This fee structure will likely change in the future as PG&E makes changes to its Net Energy Metering program.

The primary difference between secured and unsecured solar loans is that secured solar loans require that you promise an asset, usually your home, as collateral for the money that you borrow. Unsecured solar loans do not, but their interest rates are generally higher to compensate for the increased risk taken on by the lender.

Lease and Power Purchase Agreement (PPA) contract periods can vary, but a 20-year contract is typical.

At the end of your contract, you’ll need to work with your solar provider to determine if you’ll keep the solar system on your home (there may be a cost associated with this) or have it removed. Your options should be written into your initial contract.

Typically the contract is sold to the new home buyer, but sometimes there are complications. The options you have in this situation should be outlined in your initial contract with the solar installer.

If your roof needs to be replaced during the life of your solar system, a professional will need to uninstall and reinstall the part of the system that is on the roof. The cost for this service typically ranges from about $500/kW to $800/kW of solar capacity.

Often your standard homeowners policy will cover the solar equipment installed as part of your system. In some cases, a rider may be required on your homeowner’s policy. It’s best to check with your insurance carrier.

The Net Metering process rolls-over credits for the eleven months of the NEM period, on the twelfth month the account is ‘trued-up’ and the new NEM period begins.


Solar systems consist of various components, but the key ones are the solar panels and the inverter(s). Solar panels have been in use for many years and are generally warranteed for 25 years. The reliability of an inverter depends on the type. Microinverters are quite reliable and are also often warranteed for 25 years. Central inverters, however, are generally warranteed for 10 – 12 years and can be expected to fail and require replacement before the end of the 25 year normal life of a solar system.

Central (also known as string) inverters generally come with a 10- to 12-year warranty, but many manufacturers offer a warranty extensions to 20 years at a cost of several hundred dollars. Microinverters generally come with a 25-year warranty.

Rinsing or washing the panels a few times a year will help keep the system operating at its best. Washing can be done with a garden hose and should be done early in the morning before the panels get hot. There is a small chance that spraying cold water on hot solar panels can cause damage.

This varies based on how you choose to install your system. Most Power Purchase Agreements (PPAs) and Lease Programs include the maintenance costs for the life of the contract. If you directly purchase the equipment or take out a loan for it, you (as the owner) have the responsibility.

Most Power Purchase Agreements (PPAs) and Lease Programs cover maintenance (caused by equipment malfunction) for the life of the agreement. In these cases, the equipment will be maintained at no cost to the homeowner.

Steps to go solar

The size of your solar energy system will depend on a variety of factors, including how much electricity you use on a monthly basis, the weather conditions where you live, the amount of shade that falls on your roof, the electricity rate plan you’re on with your utility, etc. Your Dashboard will provide a rough estimate of an appropriate system size, but to delve deeper, it’s best to obtain estimates from several solar installers to who can perform more-detailed analyses.

If your roof has less than 10 – 15 years of life left, you should seriously consider reroofing prior to installing solar. This is because it can be costly (approximately $500/kW to $800/kW) to remove and reinstall the system’s panels and roof mounting hardware if you need to replace your roof after going solar. A roofer or solar professional can help you determine the amount of life left in your roof. Solar installers can generally coordinate with your roofer if you wish to have solar installed at the same time as you reroof.

Typically an installer will respond in 1 – 3 business days with a preliminary quote. A detailed (final) quote often requires a site survey of your home and may take another 2 weeks or more depending on when the survey can be scheduled.

An actual solar installation is typically completed within a day or two. An inspection by the city is then typically scheduled within a week after the installation is complete. When scheduling an installation, there can be significant wait times based on the solar provider’s backlog.

PG&E will normally do this within one or two weeks for simple solar installations.

While approval is typically required by a HOA before a solar system is installed, the California Civil Code (Section 714) is written to prevent an HOA from blocking the installation of a solar system. An HOA can place requirements on a system, but these requirements can’t increase the price of a system by more than $1,000 or decrease the efficiency by more than 10%. Also, an HOA needs to make a decision on a solar installation request within 45 days. You should check with your HOA on its solar policy.


As a credit, you take the amount directly off your tax payment, rather than as a deduction from your taxable income. Other than the cost of the system, there’s no limit to the dollar amount of the credit.

To claim the credit, you must file IRS Form 5695 as part of your tax return; you calculate the credit on the form, and then enter the result on your 1040. If you end up with a bigger credit than you have income tax due you can’t use the credit to get money back from the IRS. Instead, generally, you can carry the credit over to the following tax year. However, it is not yet clear whether you can carry unused credits to years after the solar credit expires.

You can’t claim a credit for installing solar power at rental properties you own, unless you also live in the house for part of the year and use it as a rental when you’re away. You’ll have to reduce the credit for a vacation home, rental or otherwise, to reflect the time you’re not there.

The City of San Francisco provides an incentive for its residents who choose to install solar panels.