Home Solar Savings Calculator

For most US homeowners with a south- or west-facing roof and an electric bill above $100/month, solar pays back in 7–11 years and produces free electricity for 15+ years after that. The biggest variables are your utility rate, peak sun hours, and whether you can claim the 30% federal tax credit.

Homes in high-rate states like California, Massachusetts, or Hawaii see the fastest payback. In low-rate states like Washington or Louisiana, payback can stretch past 12 years — solar still saves money, just more slowly.

The federal Investment Tax Credit is 30% of the total installed cost through 2032: panels, inverter, racking, wiring, permits, and labor all count. You claim it on Form 5695 the year your system is placed in service.

You must own the system to claim it. Cash purchases and solar loans both qualify. Leases and Power Purchase Agreements (PPAs) do not — the leasing company claims the credit, not you.

Cash purchase gives the highest lifetime savings and shortest payback. Solar loans let you keep the ITC and add 1–3 years to payback depending on the rate — total 25-year savings are nearly identical to cash if rates are reasonable.

Leases and PPAs require no upfront cost, but you give up the 30% tax credit and any state incentives. Total savings over 25 years are typically 40–60% lower than owning. They can still make sense if you can't use the tax credit or don't want long-term ownership.

Net metering lets your utility credit you for excess solar power you export to the grid. This calculator assumes a 1:1 credit — every kWh you send back offsets a kWh you later draw. That's still standard in most of the US.

Some states have moved to lower export rates: California's NEM 3.0 credits exports at roughly 25% of the retail rate, which can cut bill savings 20–40% for typical homes without batteries. Check your utility's current net-metering policy before signing a quote.

The math is standard solar engineering: annual usage from your bill, system size from NREL peak sun hours, and an 0.8 derate factor for real-world losses (panel temperature, inverter, wiring). Cost assumes $3.00–$3.50 per installed watt — the 2024 US average for residential systems.

Actual quotes vary by installer, roof complexity, equipment brand, and local incentives that aren't modeled here (state rebates, SREC markets, utility-specific programs). Use this calculator to size up the opportunity, then get 2–3 quotes before signing anything.

Modern monocrystalline panels carry 25-year production warranties and typically still generate at least 85% of their rated output at year 25. The cells themselves often keep producing usable power past 30 years.

The inverter is the part most likely to need replacement during the system's life — most last 10–15 years. Budget $1,500–$3,000 for one inverter replacement; microinverters and hybrid inverters carry longer warranties (20–25 years) but cost more up front.