How does solar power work?

1. Your solar installation

Solar panels: Solar panels are made up of photovoltaic (PV) cells, which convert sunlight into direct current (DC) electricity.

2. Inverter: An inverter converts the DC electricity generated by solar panels into the alternating current (AC) electricity used in most homes.

3. Monitoring system: A monitoring system sends information about your solar installation, including the amount of energy it generates, to your solar provider, to maintain optimal system performance.

4. Utility grid: Your solar system is still connected to a local utility grid to provide power after sundown. Connection to the grid also allows your solar system to return to the grid any excess clean energy your system generates during the day. A utility meter measures your power consumption and solar output.

How much maintenance is required?

Most solar installations will require little maintenance during the life of the system, and some proactive care may help you maximize the value of your investment. For example, if you live in a dusty environment, periodic washing of the panels may help increase electricity production, and inverters may need replacing, which normally occurs after the 10+ year warranty term.

How long do solar systems last?

The lifespan of a solar installation depends on the local environment and the durability of the system you purchase. A high quality solar installation can last more than 30 years.

What if there is a cloudy day?

Solar systems produce less electricity on cloudy days. The great majority of homes with solar still connect to the electric grid, drawing power from the grid when needed.

What if I'm not using electricity when the system is producing power?

In many U.S. states there is a policy called "Net Metering" which means the utility credits a homeowner for solar energy that is not consumed by the home. Those net metering credits are used up when the home takes power from the utility.

What if net metering is not allowed in my area?

It is still possible to install solar power, but any solar power not consumed by the household at the time it is produced will be exported to the electric grid, and is often compensated at rates lower than the retail electricity rate. The actual amount of solar electricity exported to the grid will depend on a variety of factors, including the total amount of electricity consumed, the size of the solar installation, and the degree to which electricity consumption occurs at the same time as solar production.

While actual values for a house will depend on the specific electricity usage patterns in that house, our estimates are based on the relationship between the total solar electricity production and the total amount of electricity consumed by the household. The larger the solar installation is relative to the household electricity consumption, the higher the estimate of percentage of solar electricity exported to the grid.

What are the risks to getting solar power?

Before deciding to go solar, make sure to select a provider with a good track record and an understanding of how to install and maintain solar systems. When properly installed and maintained, solar panels should not pose any danger to your home. Issues related to the installation and operation of a solar system are relatively uncommon, but can include PV systems catching fire, roof leaks, and hail and/or wind damage. For more information, talk with your provider.

Will my projected solar savings match actual savings throughout the life of system?

Actual savings can vary from projected savings for a variety of reasons. Fast-growing trees can shade solar installations, reducing production over time. Utilities can change how much they charge their customers for electricity, changing the savings from solar. Policies that are beneficial to solar installations may change (e.g., Net Metering). For states without net metering, savings may also vary by the amount of solar electricity consumed in the household compared to the amount exported to the grid.

What makes a roof good for solar?

The best solar roofs have large areas with South or Southwest exposure, little shade, and a roof in good condition.

What if my roof is really old?

If your roof needs to be replaced, it may make sense to replace the roof and install solar at the same time. Some providers offer a service to remove and replace a solar installation if you get a new roof in the future.

What if I have to move after a few years?

This varies by solar company, but typically you'll have the option to transfer a financed system to the new homeowner (with their consent), or buy out the rest of the contract and leave the system with the new homeowner or even bring it with you for installation in your next home. If you purchase the solar system, it's yours to handle how you would like.

Why are some parts of the roof sunnier than others?

Roof orientation matters. In the U.S., north-facing roof faces get less sun than south-facing roofs. Shading also plays a big role, whether from trees, chimneys, or nearby buildings.

What if I want to buy a high power consumption device in the future, such as a swimming pool or electric vehicle? Can I oversize my system relative to my current electricity consumption?

Sometimes you can. Different utilities have different rules on this question. Some utilities may limit the installation size to a proportion (e.g., 120%) of the electricity consumed over the prior year.

What if I rent an apartment or rent my home?

Most solar solutions are geared toward homeowners, but there are some options for renters. For example, some utilities offer green energy options, and in some states community solar programs allow people to buy solar power from remote solar installations.