Solar Panels for Your Home: Frequently Asked Questions

From installation to costs and more, we answer every solar panel FAQ.

Solar panels on model house with architectural drawing

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If you have a lot of questions about whether you should add a solar energy system to your home, that's a good thing. It's an important undertaking that requires budgeting and both short-term and long-term planning.

In considering solar panels for your home, you may be wondering: What are my current needs? What are my long-term needs? Can I afford a solar system, how will I pay for it, and is it worth it?

Fortunately, as with the costs, most of the mental and physical labor is upfront. Once the panels are on your roof, there's little maintenance and (in most cases) few headaches. In this article, we walk you through the process and answer the big questions you might have.

Before the Installation

This decision phase includes more than the debate of whether you want solar panels or not. Here are some additional considerations:

How do I figure out how much energy I'll need?

Your rooftop solar system should be able to produce enough electricity to meet your average annual electricity needs. Review your utility bills for the past year (or more) to determine that amount. The American average is around 11,000 kWh per year, or 30 kWh per day.

What Are Kilowatts and Kilowatt-Hours?

A kilowatt (kW) (or 1,000 watts) is a measurement of how much power a solar system can produce at any one time. A kilowatt-hour (kWh) is a measurement of how much electricity you use over the course of one hour.

How many solar panels will I need?

Calculating how many panels you'll need is easier than you think, but it depends on how much power your panels produce, how efficient they are at producing it, and how much sunshine hits your roof.

If you need, for example, 30kWh per day and your roof gets five hours of sunshine per day, you'll need a 6 kW system (30÷5=6). If the panels you're going to purchase can produce 300 watts of power, you'll need 20 of them to produce 6 kW (300x20=6,000).

What if my roof doesn't get enough sun?

Not every American household gets enough sun to support rooftop solar. If your roof is shaded by a neighbor's property, you may be able to negotiate a solar easement. If not, an affordable alternative is to join a community solar farm, which allows you to provide your home with solar electricity without installing anything on your property.

What if my roof faces east-west rather than north-south?

While a south-facing roof (in the Northern Hemisphere) will capture more energy from the sun, other orientations don't rule out solar. There can even be advantages to an east-west facing roof, depending on where you live. Solar trackers can change the orientation of your panels throughout the day, but they're usually too heavy for a normal roof.

Does it matter that it snows a lot where I live?

Solar panels on residential roof with snow

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Snow cover is a common concern, but except for wet, heavy snow or ice that covers your roof, your panels will do fine. In most circumstances, they will continue producing electricity, and the slope and heat from the panels clear them relatively quickly. Light reflected from the snow can even boost your panels' output.

Costs and Payments

One of the first questions people ask about solar energy is how much it would cost them. Along with that, there are other cost questions that follow.

How do I estimate the cost of solar panels?

The average cost to install a solar system is about $2.81 per watt. If you figure out you'll need a 6 kW system, your system would cost $16,860.

What government incentives are there to lower the cost of solar panels?

There are federal incentives for installing solar panels. Keep an eye on federal legislation, as the amount offered may change—hopefully for the better. Many states also have tax credits and rebates as well.

How does solar leasing work?

Leasing solar panels is like leasing a car: You don't own the panels, but get to enjoy the use of them for the length of the lease, usually 20 years. At the end of the lease, you may have the opportunity to buy the panels.

The benefit of a lease is that you save money on your electricity bill without the cost of installing the system. The downside is that you don't get any tax credits or own the panels, so they never pay for themselves.

How do I pay for solar panels?

As with other large purchases, it's less expensive to pay cash, since you don't have interest rates to pay. But solar loans are also available, often at lower interest rates than going through a local lending institution. Some states have green banks to help with financing, and your installer may also have arrangements with financial institutions.

How will solar panels affect my electricity bill?

Nearly every U.S. state has a net metering program, where solar customers get credit on their electricity bills for some or all of the electricity that they send into the grid. Over the course of a year, you'll get credit in the months when you produce more electricity than you consume (usually spring and fall) and use that credit during those months when you're consuming more electricity to heat or cool your home.

Is adding a battery backup worth it?

It depends on what you mean by “worth it.” Currently a solar plus battery storage system is financially uneconomical. But if having a resilient source of electricity during natural disasters or other power outages is important, there are many good options for battery storage that may make the extra cost worth it.

How long is the payback time?

The average cost of grid electricity in the U.S. is around $0.14/kWh. The average cost of solar electricity is $0.08 to $0.10/kWh. Your payback time depends on the price of electricity in your area, the cost of your solar system, whether or not you took a loan to pay for it, how much electricity you use, and a few other factors. The average time it takes for the system to pay for itself is 7 to 12 years.

The Installation Process

After deciding to invest in solar panels, another batch of questions comes up around installation.

How do I find a good solar panel installer?

Treehugger has its own list of the best national solar installation companies, but a local, certified installer may have more experience working in your area.

What needs to happen between signing a contract and the installation?

Your installer will draw up a detailed plan and spec sheet. Permits will need to be obtained from your municipality to pass building codes, electricity codes, fire codes, and perhaps codes specific to solar PV systems. Additional permits may be needed if you're part of a homeowner's association or live in a historic district. Inspections to make sure your roof and wiring are up to code and able to support rooftop solar are likely also required. Your utility company will also inspect the system before it activates the system's connection to the grid.

What actually gets installed?

A rooftop solar system includes panels, a rack that they are mounted on, sealing materials to protect your roof, an inverter which converts the DC electricity that the panels produce into AC electricity that your house uses, wiring to get that electricity into your house, junction boxes to contain the wiring, an emergency shutoff panel, and other mechanical hardware.

How long does it take to install solar panels?

Depending on how big a job it is, the actual installation can take one to three days. What takes more time are all the inspection, permitting, and interconnection processes. It could be three months from the time you sign a contract until you have solar power running into your house.

Can I install my own solar panels?

Installing heavy solar panels on a slanted roof and connecting them to your electrical system has its challenges as well as risks to life and limb. That said, it is possible for two or three people to install a system over the course of a weekend. A licensed electrician may be required to connect the wiring.

Doing it yourself can save you thousands of dollars, but an installer will be more familiar with navigating the inspection, permitting, and interconnections necessary to get your system up and running.

After the Installation

The installation is complete. Now what?

How long will my panels last?

The standard warranty for a solar system is 25 years. Solar panels lose efficiency slowly, at roughly 0.5% per year, so a 20-year-old solar system can still generate 90% of its original output. In 20 years, your electricity needs may be greater or smaller than when you originally installed your panels.

What if I plan on buying an electric car in the future?

Rooftop solar system on garage with electric vehicle charging

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It's far cheaper to charge an EV than it is to fuel a gas-powered car. Driving on sunshine makes it even cheaper. Your utility company is unlikely to allow you to plan for the future by installing a larger solar system than you currently need—unless you don't connect all of your panels to the grid right away. Ask your installer what options you have.

What if the power goes out?

Unless you have an off-grid system, most solar installations are tied to the electricity grid, so if the power goes out in your neighborhood, it goes out at your house, too. For safety reasons, your solar system can't be sending electricity into the grid if utility workers are going to be making repairs to power lines. If you have a battery backup system, however, you may have an automatic shutoff that disconnects your system from the grid and allows you to keep your lights on.

How much solar panel maintenance will I need to do?

Solar panels have no moving parts, so there's little maintenance. It's wise to have the electrical systems inspected by your installer on an annual basis. As for cleaning, if you live in an area where it rains or snows regularly, the rain or snow melt will act as a natural cleaning solution. But it can't hurt to remove dirt, dust, or other obstructions from your panels to improve their efficiency.

What if I need to replace my roof?

Solar panels can protect your roof and allow it to last longer. That's good news, since replacing a roof once solar panels are installed is not easy or cheap, so it's recommended that you consider doing any roof repairs before you put panels up there. Your solar installer will also need to determine if your roof is structurally sound enough to support solar panels. If it's not, consider community solar.

What if I want to sell my home?

Rooftop solar systems can be an asset to selling a house. A recent study from Zillow found that a house with solar panels sold for 4.1% more than comparable homes without them. With the median American home price of around $350,000, that's around $14,350—almost the entire original cost of a solar system.