Most American homeowners pay between $2.50 and $3.50 per watt for a professionally installed rooftop system before incentives. With a typical home system of 7 to 8 kilowatts (kW), that works out to roughly $18,000 to $28,000 up front.
Price per watt is the single most useful number for comparing quotes. Divide the total system price by its size in watts. A $21,000 quote for a 7 kW (7,000 W) system costs $3.00 per watt.
What pushes the price up or down
System size: bigger systems cost more in total but less per watt.
Equipment: premium panels and microinverters can add 10-20%.
Roof: steep, tile, or multi-level roofs take more labor.
Location: permitting, labor rates and local competition differ by state.
Extras: electrical panel upgrades, critter guards and batteries add cost.
The bottom line
Get at least three quotes and compare them per watt, along with equipment and warranties. A quote far below the local average can be a warning sign as often as a bargain.
Until the end of 2025, homeowners could claim a 30% federal tax credit on the cost of solar, batteries and other clean energy upgrades. That residential credit ended for systems installed after December 31, 2025. Some systems owned by a third party (leases and power purchase agreements) may still benefit from business credits, subject to deadlines, so ask installers how they handle this.
Losing the credit stretches the typical payback period by a few years. But three things still work in solar's favor: utility rates have been rising faster than inflation, equipment prices remain low, and a well-installed system keeps producing for 25 to 30 years or more.
Solar tends to pay off best when
Your electricity rate is above about 15 cents per kWh.
Your roof gets good sun and faces south, east or west.
Your state or utility offers rebates, credits or fair net metering.
You plan to stay in the home for at least 7 to 10 years.
Run your numbers in the Rayern calculator. It shows payback both with and without local incentives, so you can see the honest picture for your address.
Your panels often make more power than you use at midday. That extra power flows to the grid, and how your utility credits it can make a big difference to your savings.
Net metering
Under classic net metering, each kWh you export earns a credit equal to the retail price you pay for power. Your meter effectively spins backward. This is the most generous arrangement.
Net billing
Under net billing, exports earn a lower rate, often based on the utility's wholesale or avoided cost. More states have moved in this direction. When exports are worth less, using your solar power yourself, or storing it in a battery, becomes more valuable.
Tip: ask each installer which export rules your utility uses and how they modeled them in your savings estimate.
Quality solar panels are built to last 25 to 30 years and often keep working well beyond that. They lose a little output each year, called degradation. Modern panels typically lose 0.25% to 0.5% per year, so after 25 years they still produce around 88% to 94% of their original output.
Inverters usually wear out first. String inverters often last 10 to 15 years, while microinverters commonly carry 25-year warranties. Budget for one inverter replacement over the life of a string system.
Maintenance is minimal: rain cleans most panels, and monitoring apps alert you if production drops.