For years, a 30% federal tax credit cut the cost of homeowner-owned solar systems. Legislation passed in 2025 ended that residential credit for systems placed in service after December 31, 2025. Solar can still pay off in many homes, but the maths has changed. Here is how to estimate your own payback.
Key Takeaways
- Simple payback = net system cost ÷ annual bill savings.
- Annual savings depend on how much solar you use directly and how exports are credited.
- State and utility incentives may still reduce costs; verify current programs.
- Consider financing costs, maintenance and how long you plan to stay in the home.
Step 1: Net system cost
Start with the installed price. Subtract any state or local rebates or incentives you qualify for. Confirm current federal incentives with IRS guidance and your installer.
Step 2: Annual production
Use the installer’s production estimate in kWh per year.
Step 3: Split production
Estimate how much production you will use directly and how much you will export. Without batteries, many homes use a portion directly and export the rest.
Step 4: Value each part
- Self-consumed kWh × your retail rate
- Exported kWh × your export credit rate
Add them for annual savings.
Step 5: Simple payback
Payback years = net cost ÷ annual savings
Example
- Net cost: $24,000
- Production: 9,000 kWh
- Self-consumption: 50% (4,500 kWh) at $0.25 = $1,125
- Exports: 4,500 kWh at $0.08 = $360
- Annual savings: $1,485
- Payback: about 16 years
Higher retail rates, better export credits or more self-consumption shorten payback.
Other factors
- Rate increases can improve savings over time.
- Degradation slightly reduces output each year.
- Maintenance and inverter replacement.
- Financing interest.
- Home value effects vary by market.
Improving the self-consumption share
In the example, raising self-consumption from 50% to 70% changes the maths:
- Self-consumed: 6,300 kWh × $0.25 = $1,575
- Exported: 2,700 kWh × $0.08 = $216
- Annual savings: $1,791
- Payback: about 13 years
Ways to shift more usage into sunny hours include running dishwashers and laundry during the day, charging an EV at midday when possible, pre-cooling the home in summer and using timers on pool pumps and water heaters.
Lifetime value
Panels commonly carry performance warranties of around 25 years. If a system pays back in 12 to 16 years, the remaining years produce savings with relatively low costs, aside from inverter replacement and maintenance.
A simple lifetime estimate: annual savings × expected years of operation, minus net cost and expected replacement costs. Including modest electricity price increases improves the picture; assuming flat rates gives a conservative view.
Financing
If you borrow to pay for solar, include interest. A loan with a high interest rate can wipe out much of the savings. Compare loan terms with the return you would expect from other uses of the money.
When solar may not pay off
- Low electricity rates
- Heavy shading
- Poor roof orientation
- Low export credits combined with low daytime usage
- Plans to move soon, unless solar is valued by buyers in your market
Frequently Asked Questions
Is solar still worth it without the federal credit? In areas with high rates and good export credits, it can be.
Do leases change payback? Leases and PPAs replace upfront cost with monthly payments; compare total costs.
Should I wait for prices to drop? Waiting has trade-offs; you lose savings meanwhile.
Do I need a battery? Not always; consider your goals and rates.
The bottom line
Use your bills, realistic export rates and current incentives to calculate payback, and compare it with how long you plan to stay.
