Over 25 years, an average home that stays on the grid pays about $59,500 to $99,100 for electricity, depending on how fast prices rise. The same home with solar pays about $42,400 to $53,400 in total, including the system, upkeep and the bills that remain. In our model, solar comes out ahead by roughly $17,000 to $46,000, but only if the system is priced fairly and paid for sensibly.
This guide compares the two paths year by year, shows how the answer changes with electricity rates and financing, and lists the factors the math leaves out.
Key takeaways
- Solar wins on cost in most scenarios where electricity prices rise at least 2 % a year and the system is paid for in cash or with a low-fee loan.
- The break-even point is typically 10 to 12 years at an average rate of 20 ¢/kWh, and 7 to 15 years across the range of 30 ¢ to 14 ¢.
- Staying on the grid has no upfront cost, but you carry all the risk of future rate increases.
- A 20-year loan at 7 % can erase most of the savings, especially if prices stay flat.
- Savings are larger in high-rate states and smaller in low-rate states with weak export credits.
How we compared the two options
To keep the comparison fair, we used one household and one set of assumptions:
- Usage: 11,000 kWh per year, close to the national average.
- Grid price: 20 ¢/kWh in the base case, plus a fixed charge of $15 per month.
- Solar system: 7.6 kW at $2.95 per watt, or $22,420, with no federal tax credit (it ended for systems installed after 2025) and no state incentives.
- Offset: the system cuts energy charges by 85 % in year one. Production falls 0.5 % per year.
- Remaining costs: the fixed charge and the unoffset 15 % of energy charges stay on the bill.
- Upkeep: $100 a year for cleaning and checks, plus a $2,000 inverter replacement, for $4,500 over 25 years.
- Price growth: electricity prices rise 0 %, 2 %, 3 % or 4 % per year.
The figures are not adjusted for the time value of money, and they are estimates, not predictions. Your results will vary.
What staying on the grid costs over 25 years
The grid-only path has one cost: your electricity bill. In year one, our household pays 11,000 × $0.20 + $180 = $2,380. What happens next depends on price growth.
| Yearly price growth | Year 1 bill | Year 25 bill | 25-year total |
|---|---|---|---|
| 0 % | $2,380 | $2,380 | $59,500 |
| 2 % | $2,380 | $3,830 | $76,200 |
| 3 % | $2,380 | $4,840 | $86,800 |
| 4 % | $2,380 | $6,100 | $99,100 |
Residential electricity prices in the US have generally risen over the long term, though not evenly, and the pace varies by state. A long-run growth rate of 2 % to 3 % is a reasonable planning range, but nobody knows what will happen.
What going solar costs over 25 years
The solar path has three parts:
- Upfront cost: $22,420 for the system.
- Upkeep: about $4,500 over 25 years, mainly an inverter replacement.
- Remaining electric bills: the fixed charge plus the 15 % of energy charges the system doesn’t offset.
Subtract the savings from the grid bill, add the first two items and you get the total cost of the solar path.
Head-to-head: 25-year totals at 20 ¢/kWh
| Yearly price growth | Grid only | Solar (cash) | Solar saves | Break-even |
|---|---|---|---|---|
| 0 % | $59,500 | $42,400 | $17,100 | about 12.3 years |
| 2 % | $76,200 | $47,000 | $29,200 | about 11.1 years |
| 3 % | $86,800 | $49,900 | $36,800 | about 10.6 years |
| 4 % | $99,100 | $53,400 | $45,700 | about 10.2 years |
Break-even is the point when your cumulative savings equal the upfront cost of $22,420, before the inverter replacement. Even if prices never rise, solar still comes out ahead in this scenario because it lasts longer than the payback period. The faster prices climb, the bigger the gap.
How electricity rates change the result
The next table assumes electricity prices rise 3 % a year and keeps the same 7.6 kW system and 11,000 kWh of usage.
| Electricity rate | Grid only (25 years) | Solar (cash) | Solar saves | Break-even |
|---|---|---|---|---|
| 14 ¢/kWh | $62,700 | $45,000 | $17,700 | about 14.5 years |
| 20 ¢/kWh | $86,800 | $49,900 | $36,800 | about 10.6 years |
| 30 ¢/kWh | $126,900 | $58,200 | $68,700 | about 7.4 years |
Solar’s advantage grows quickly with the rate. At 14 ¢/kWh the system still saves money in this model, but the break-even point sits close to the middle of the system’s life. In low-rate states with weak export credits, the real result can be worse than shown, so check your utility’s rules.
How financing changes the comparison
Paying cash gives the best results. A loan adds interest. Here is the same 20 ¢/kWh household with a $22,420 system financed over 20 years at 7 %. The payment is about $174 per month and the total repaid is about $41,700.
| Yearly price growth | Solar saves (cash) | Solar saves (7 % loan) |
|---|---|---|
| 0 % | $17,100 | about –$2,200 |
| 3 % | $36,800 | about $17,500 |
If prices don’t rise and you finance at 7 %, solar costs slightly more than the grid over 25 years. If prices rise 3 % a year, it still saves roughly $17,500. Dealer fees, which can add 10–30 % to a loan’s principal, would reduce the savings further. Always compare the cash price and the financed price.
What the numbers leave out
Reasons to prefer solar beyond the math
- A hedge against rate increases. Solar locks in the cost of most of your electricity for decades.
- Home value. Owned systems often add to resale value, particularly where electricity is expensive.
- Backup power. With a battery, solar can keep your lights on during outages. That adds cost but also real value in storm-prone areas.
- Environmental benefits. Some owners value lower emissions on their own terms.
Reasons to stay on the grid
- No upfront capital. The money can go into debt reduction, retirement accounts or home repairs that offer a better return.
- Flexibility. You can move without worrying about a system you won’t recover.
- No policy risk. Net metering rules can change, which would lower the value of exports.
- No roof constraints. A shaded, old or complicated roof can make solar a poor fit.
- Technology. Panels and batteries may get cheaper, though waiting also means paying higher bills in the meantime.
When solar is the better choice
- Electricity costs 18–20 ¢/kWh or more.
- Your utility credits exported power at or near the retail rate.
- You have an unshaded roof in good condition.
- You expect to stay in your home for at least 10 to 12 years.
- You can pay cash or get a low-fee loan.
When staying on the grid may be the better choice
- Electricity costs less than 12–14 ¢/kWh and exports earn little.
- Your roof is shaded or needs replacing soon.
- You may move within five to seven years.
- The only financing offered carries high fees or interest.
- You have higher-return uses for the money, such as paying off high-interest debt.
Alternatives if solar doesn’t fit
You can still lower your bill without installing panels:
- Efficiency upgrades. LED lighting, insulation, a heat pump, a smart thermostat and efficient appliances cut usage permanently.
- Better rate plans. A time-of-use plan can lower costs if you can shift use to off-peak hours.
- Community solar. In states that allow it, you subscribe to a share of a solar farm and receive bill credits, with no roof and little or no upfront cost.
- Green tariffs. Some utilities offer renewable energy plans with stable rates.
How to run your own 25-year comparison
- Collect 12 months of bills and record your annual kWh and your total cost.
- Get three quotes and record the net price, the system size and the estimated production.
- Estimate your savings by multiplying production by the value per kWh, using the retail rate for the power you use and your utility’s export rate for the rest.
- Choose a price growth rate between 0 % and 3 % and project both paths over 25 years.
- Add upkeep and an inverter replacement to the solar path.
- Compare totals and the break-even year. Test a worse case with a lower savings figure, so the decision holds up if conditions change.
Frequently asked questions
Is solar cheaper than the grid over 25 years?
In most of our scenarios, yes. It is cheaper when electricity costs about 18 ¢/kWh or more, prices rise at least a couple of percent a year and you don’t pay heavy interest or fees. In low-rate markets the advantage shrinks or disappears.
How long does it take for solar to break even?
Roughly 10 to 12 years at an average rate and about 7 years in high-rate states. In low-rate states, 14 years or more.
What if electricity prices fall or stay flat?
Solar still beat the grid in our cash scenario with 0 % growth, but by a smaller margin. With a 7 % loan and flat prices, the grid came out slightly cheaper.
Do solar panels last 25 years?
Most panels carry 25-year performance warranties and often keep producing well beyond that. Inverters usually need replacing once, around year 10 to 15.
Should I wait for solar prices to drop?
Maybe, but waiting has a cost. Every year without solar is a year of full utility bills, and policy changes can make the deal better or worse. Compare the cost of waiting with the possible price drop.