Solar panels for your home: what to check before you go solar

How solar panels work, explained simply

Each panel, or module, is made of photovoltaic (PV) cells that turn sunlight into direct current (DC). Panels are wired together into an array on racking that holds them toward the sun, and an inverter converts the DC into the alternating current (AC) your home uses. When the panels produce more than the house needs, the surplus flows out to the grid through a meter that measures both directions. At night and on dull winter days you draw power from the grid as before. A battery can store some daytime surplus for the evening or for a power cut. Solar reduces the kilowatt-hours (kWh) you buy, but the FTC points out that you still pay the utility's fixed charges, and production is lowest in winter.

Pros and cons of solar panels for your home

In the UK, the Energy Saving Trust estimates payback at about 9 to 12 years with export payments, depending on where you live and how much of the power you use at home.

Is your roof right for solar panels

Roof age deserves special attention because panels outlast many roofs. DOE suggests replacing a roof that will soon need it before the panels go on, and a DOE fact sheet notes that if the roof has to be replaced later, the installer must remove and reinstall the system. If you have a roof leak or soft decking, fix that first: see roof leak.

If your roof is unsuitable, or you rent, community solar lets you subscribe to a share of a larger array elsewhere.

How many solar panels you need

Start from your bills, not from the size of the roof.

1. 01

   Gather 12 months of bills

   Add up the kWh you used each month. The seasonal pattern shows whether summer cooling or winter heating drives your use.

2. 02

   Cut waste first

   DOE recommends efficiency upgrades before solar, because every kWh you save is one you do not need to generate. Sealing air leaks and topping up attic insulation are good places to start.

3. 03

   Run a free estimate

   NREL's PVWatts calculator estimates monthly production for any address, roof direction and tilt.

4. 04

   Compare each bid with your use

   Treasury's consumer advisory suggests asking how many kWh per month the system will produce on average and how that compares with your usage, so you avoid buying more panels than you need.

5. 05

   Plan for changes

   An electric vehicle or a heat pump will raise your use; tell the installer.

For scale, NREL uses an average home system of about 7.15 kW, within a typical range of 3 to 11 kW.

Net metering and export payments

What you are paid for the electricity you send to the grid has a big effect on the value of solar, and it varies widely. DOE notes that net metering depends on your state and your utility, on rules such as system size and on how bill credits are designed, and that it is rarely as simple as a meter running backward. Ask your utility these questions before you sign anything:

• Do you offer net metering or another export credit, and how does that rate compare with what I pay for power?
• Do unused credits carry over, and for how long?
• Which fixed charges will stay on my bill?

In the UK, payment for exported electricity comes through the Smart Export Guarantee (SEG). Certain electricity suppliers must offer an export tariff, but each sets its own rate, contract length and terms, so compare them; Ofgem requires the rate to be above zero.

Buying vs leasing solar panels: loans, leases and PPAs compared

With a lease or a PPA, the tax credits, incentives and renewable energy certificates go to the owner, so check how the price reflects that. More points from the FTC and Treasury:

• PACE financing adds the loan to your property tax bill as a lien that can take priority over your mortgage. Missing a payment can lead to default and foreclosure, and some mortgages do not allow this kind of lien.
• A UCC-1 lien filed against the system can put off buyers when you sell, and the lender may require the loan to be repaid or taken over.
• Ask whether a lease or PPA can transfer to a buyer if you sell, and on what terms.
• Think about how long you will stay. Treasury's example: if the panels take 15 years to pay off and you plan to move in five, other options may suit you better.

Incentives change, sometimes from one year to the next, and a tax credit only helps if you owe enough tax to use it. Confirm your eligibility with the IRS or a tax professional, and look up state, local and utility programs by ZIP code in DSIRE, the incentives database DOE points to. Treasury warns against anyone who says tax credits will cut your cost without first confirming that you qualify.

How to spot solar sales pressure and scams

Warning signs named by the FTC and Treasury:

• Pressure to decide quickly, or a contract handed over without time to read it.
• A request to pay in cash.
• Exaggerated savings, "free" panels, or claims that the federal government pays for your system.
• Warnings that energy prices will skyrocket, so you must sign today.
• Signing on the seller's tablet without a copy you can keep.

Before you sign, check that the contract states:

• System size, expected annual output and any production guarantee, with what happens if output falls short.
• The total price, including permits, and every fee.
• Equipment, performance and workmanship warranties, and who repairs the roof if it leaks around the mounts.
• Your right to cancel and its deadline. Treasury's advisory notes that the right to cancel lasts at least three days from signing; ask how to use it.
• For leases and PPAs: payment increases, early termination fees and your options at the end of the term.

If something goes wrong, raise it with the company in writing first. If that fails, report it to the FTC at ReportFraud.ftc.gov and to your state attorney general.

Permits, inspection and connecting to the grid

Home solar must meet local building, fire and electrical codes, so expect a permit, an inspection and a separate utility approval to connect. Ask the installer, in writing:

1. 01

   Who applies for the permits

   And are permit and inspection costs included in the bid?

2. 02

   Who files the interconnection application

   And when do they expect the utility to approve switching the system on?

3. 03

   Will the meter be changed

   Net-metered homes get a meter that records both the power you import and the power you export.

4. 04

   How are roof penetrations sealed

   And does the workmanship warranty cover leaks around the mounts?

In the UK, roof-mounted panels on houses in England may count as permitted development, so planning permission is often unnecessary, but limits and conditions apply, and listed buildings and conservation areas need extra care. Check with your local council before work begins.

Solar panel maintenance and monitoring

Rooftop systems have no moving parts, and a DOE fact sheet says regular rain usually keeps panels clean enough.

• Monitoring: compare the app's monthly output with the installer's estimate and call them if it stays well below.
• Cleaning: if panels look very dirty after a long dry spell, a gentle rinse with a hose is all the DOE fact sheet suggests.
• Snow: it usually slides or melts off within hours to a few days. After heavy snow on a low-pitched roof, a long-handled roof rake used from the ground speeds things up.
• Hail: panels are designed to resist small to moderate hail of at least 1 inch in diameter; a damaged panel can be replaced on its own.
• Insurance: tell your insurer about the system; a rider may be needed for full cover.
• Warranties: the DOE fact sheet mentions component warranties of typically 25 years and workmanship warranties of up to 10 years; terms vary, so keep and read yours.

Do you need a solar battery

Storage, usually a battery, lets you use solar power in the evening or during a power outage rather than only when the sun shines. A battery is worth discussing if your utility pays little for exported power, or if outages are frequent where you live (see our power outage guide). Ask the installer:

• Which circuits would the battery keep running in an outage, and for roughly how long?
• Can a battery be added later, and what warranty covers it?

Sources

Official US and UK guidance, checked on 27 October 2026.

• US DOE Solar Energy Technologies Office · Homeowner's guide to going solar ↗Roof orientation and slope, shade, replacing the roof first, average system size, net metering, storage, financing options, HOAs and certified installers.
• FTC · Solar power for your home ↗System lifespan, fixed charges, leases, PPAs, PACE liens, contract terms, selling your home and how to report problems.
• US Treasury · Before you purchase and finance solar panels (consumer advisory) ↗Scam warning signs, questions to ask, sizing against your usage, UCC-1 liens and the right to cancel.
• US DOE Weatherization Assistance Program · Solar frequently asked questions ↗Maintenance, cleaning, snow, hail, monitoring, warranties, insurance, reroofing and net-metered bills.
• Energy Saving Trust · Solar panels: costs, savings and benefits explained ↗Checked on 2 November 2026: PV cells, DC and inverter, cloudy days, south-facing pitched roofs, about £7,600 for a 4.5 kWp system, about one tonne of CO2 a year, Smart Export Guarantee, 9 to 12 years payback, panels lasting 25 years or more and inverters about 12, rain cleaning at 15 degrees or more, and combining panels with batteries, heat pumps and electric vehicles.
• Ofgem · Smart Export Guarantee ↗How UK export payments work and how suppliers set rates.
• Planning Portal · Solar panels: planning permission ↗Permitted development for solar panels on houses in England and checking with the local authority.