HyreSolar tools
See how many years of on-site savings it takes to recover net cost.
Simple payback is net cost divided by year-1 bill savings from self-consumed production. It is not discounted and it is not a quote. The federal homeowner credit defaults to 0% because §25D ended for systems placed in service after 31 December 2025.
What this returns at the defaults
At the defaults, a 12 kW system at $2.58/W on an 18.44¢ rate returns 14.3 years. Change the rate to 32¢ and it becomes 8.2 years. Change it to 11¢ and it becomes 23.9 years. The single largest driver of solar payback is not the system, it is your electricity rate, and that is not something a proposal can change.
Last updated . Data as of 6 August 2026.
Change any input. Default credit is 0%.
Simple payback, not discounted. Default §25D is 0%.
A quote’s $/W and a PVWatts yield beat these defaults. HyreSolar does not sell systems.
Simple payback is the year in which cumulative bill savings equal what you paid. It is deliberately crude. It does not discount future money, it assumes your rate and your production hold, and it stops asking questions the moment the two numbers meet. Its virtue is that you can check it in your head.
The comparison that matters is against how long you will own the house, not against some universal target. A 14-year payback is excellent if you are staying 30 years and irrelevant if you are moving in four. Nobody can tell you what a good payback is without knowing that, which is why we will not print a target here.
A payback longer than the equipment warranty is a warning. If the number comes back above roughly 25 years, the model is telling you the system does not pay for itself within its own working life at these inputs. That is a real answer, not a broken calculator.
Every input below is a number you can find, not one you have to guess. This is where each one comes from.
Use the DC nameplate figure, which is the number of panels multiplied by their wattage. A 12 kW system is roughly 30 panels at 400 W.
Where to find it The top line of any proposal, usually written as "system size" or "kW DC". If you only have a panel count and a wattage, our panel count calculator converts between them.
Total contract price divided by system watts. This is the only fair way to compare two quotes for different sized systems.
Where to find it Divide the quoted total by the system size in watts. A $30,960 quote on a 12 kW system is $2.58/W. Our proposal analyzer does this and unwinds a dealer fee at the same time.
Not the energy charge alone. Take the full bill and divide by the kilowatt-hours it covers, so delivery, supply and fixed charges are all inside the number.
Where to find it Your utility bill. Total amount due divided by total kWh. Delivery is frequently the larger half, which is why the energy line alone understates what a kWh actually costs you.
Annual kWh generated per kW of DC capacity. The 1,400 default is a US planning mid-band, not a figure for your roof.
Where to find it Run your address through NREL PVWatts and divide its annual kWh by your system size in kW. That is the single biggest accuracy improvement available to you here.
The share of what you generate that you use on site rather than export. This is the input people get most wrong, and it moves the answer more than almost anything else.
Where to find it If you are home during the day, have a battery, or run air conditioning on summer afternoons, it is higher. If the house is empty from eight to six, it is lower. Without a battery, 30 to 50 percent is common.
The residential credit under §25D is not available for property placed in service after 31 December 2025. Leaving 30% in the model invents a saving you cannot claim.
Where to find it Your placed-in-service date, not your contract date. See what the §25D expiry actually changed.
Size × $/W, then subtract only a credit you actually qualify for. Default credit is 0%.
Size × specific yield × self-consumption. Yield is not PVWatts unless you replace it with PVWatts.
This ignores export credit below retail and fixed charges.
Net cost ÷ year-1 savings. That is simple payback.
The formula, in full
gross = kW × 1000 × $/W. net = gross × (1 − credit). annual kWh = kW × yield × self-use. annual saving = annual kWh × rate ÷ 100. years = net ÷ annual saving.
A 12 kW system in a house on the national average residential rate, priced at the 2026 marketplace survey midpoint, with no federal credit because the system is placed in service in 2026.
Inputs
Result
14.3 years
Net cost $30,960 recovered by $2,169 of avoided electricity a year. Note what is not in that: the 5,040 kWh exported each year earns whatever the export rate is, and at most tariffs that is well below retail. If your utility pays a meaningful export credit, real payback is shorter than this model says.
The same 12 kW system, one input changed at a time. Every figure is computed by the calculator on this page.
| Change | Year-1 saving | Simple payback | Against the 14.3-year base |
|---|---|---|---|
| Base case18.44¢, $2.58/W, 70% self-use | $2,169 | 14.3 years | Reference |
| Rate 11¢ instead of 18.44¢ | $1,294 | 23.9 years | 9.6 years worse |
| Rate 32¢ instead of 18.44¢ | $3,763 | 8.2 years | 6.1 years better |
| Price $3.50/W instead of $2.58 | $2,169 | 19.4 years | 5.1 years worse |
| Price $2.00/W instead of $2.58 | $2,169 | 11.1 years | 3.2 years better |
| Self-consumption 40% not 70% | $1,239 | 25.0 years | 10.7 years worse |
| Self-consumption 100% not 70% | $3,098 | 10.0 years | 4.3 years better |
| Yield 1,000 not 1,400 | $1,549 | 20.0 years | 5.7 years worse |
| Yield 1,800 not 1,400 | $2,788 | 11.1 years | 3.2 years better |
Read the two extremes: the electricity rate swings the answer by 15.7 years across the range shown, and self-consumption by 15 years. Price per watt, the thing you negotiate hardest, swings it by 8.3.
Ranked. A proposal can change any of these without saying anything untrue, so these are the inputs to check first.
The largest single driver, and the one nobody controls. Moving from 11¢ to 32¢ takes payback from 23.9 years to 8.2. The same equipment on the same roof is a different investment in two states. Compare rates in our bill-by-state analysis.
Almost as powerful, and far more often wrong in a proposal. Dropping from 70% to 40% adds 10.7 years. It matters because exported kilowatt-hours are usually credited below retail, so a model that values every kWh at retail flatters the result.
Where the roof actually is, which way it faces and what shades it. The 1,400 default is a national mid-band; a shaded north-facing plane will not reach it. See what shade does to output.
The input you negotiate and the third most powerful. Worth pushing on, but note that beating your installer down by $0.58/W buys you 3.2 years while living in a 32¢ state buys you 6.1.
A 30% credit cuts net cost and payback by 30% proportionally. For systems placed in service after 31 December 2025 it is $0, which is why this model defaults to zero.
Degradation, rate inflation, discounting, maintenance and inverter replacement are all outside simple payback. Each of those pushes the real answer in a different direction, which is the honest reason simple payback is a screening tool and not a verdict.
Delivery is frequently the larger half of a residential bill. Entering only the supply rate can understate your true cost per kilowatt-hour by a wide margin and makes payback look far worse than it is. Divide the whole bill by the whole kWh.
It is the default on most calculators elsewhere and it is wrong for a 2026 placed-in-service date. A 30% credit that does not exist makes a 14.3-year payback look like 10.0.
Valuing every generated kilowatt-hour at full retail is the most common way a proposal overstates savings. Unless you have storage or are home all day, a large share is exported and credited at a lower rate.
There is no universal good number. Compare it to how long you intend to own the house, and if you may sell before then read what solar does to resale value.
A price per watt only includes what the contract includes. Roof work, a main panel upgrade, trenching or a battery may sit outside it, and each one lengthens real payback without appearing in this model.
It is not. It ignores everything after the break-even year, so it systematically undersells a system that runs for 25 years and oversells one that will need an inverter at year 12.
There is no universal number, and anyone quoting one is guessing about your life rather than your roof. Compare simple payback to how long you will own the house. This model’s default 12 kW at $2.58/W, 18.44¢/kWh, 1,400 kWh/kW/yr and 70% self-use returns about 14.3 years with a 0% federal credit.
§25D is not available for property placed in service after 31 December 2025. Leaving 30% in the model would invent a saving you cannot claim. If your system was placed in service by that date, set it to 30 and the payback falls proportionally, from 14.3 years to 10.0 at the defaults.
Annual kilowatt-hours per kilowatt of DC capacity. The 1,400 default is a US planning mid-band. For your actual roof, run your address through NREL PVWatts and divide its annual kWh by your system size. Moving from 1,000 to 1,800 changes payback from 20.0 years to 11.1, so this is worth doing properly.
Because exported kilowatt-hours are usually credited below retail. Valuing every kWh at full retail overstates savings under net billing and buyback tariffs. Dropping self-consumption from 70% to 40% moves payback from 14.3 years to 25.0, which shows how much this single assumption carries.
No, and the difference matters. Simple payback stops asking questions at the break-even year, so it ignores everything a system earns afterwards and ignores costs that arrive later, such as an inverter replacement. It is a screening tool for comparing options, not a verdict on whether solar is a good investment.
Because they use different denominators, and both are correct. This tool values 70% self-consumption of what the array generates. The savings calculator values an 85% offset of what the house consumes. Those are different quantities, so the same house can return 14.3 years here and about 11.8 there. Use this one when you know your system size and price; use that one when you know your usage and bill.
Your total, blended rate: the whole bill divided by the whole kilowatt-hours. Delivery charges are frequently the larger half of a residential bill, and solar offsets the kilowatt-hours that carry both. Using the supply line alone can make payback look years worse than it is.
It changes two things in opposite directions. It raises self-consumption, which shortens payback, and it raises net cost, which lengthens it. This model has no battery input, so the honest approach is to run it twice: once with the array alone, once with the battery in the price and a higher self-consumption figure, and compare.
Discounting, degradation, utility rate inflation, maintenance, inverter replacement, export credit, and any cost outside the price per watt you entered, roof work, a main panel upgrade, trenching for a ground mount. Every one of those is real. Simple payback is the number you can check by hand, which is its whole purpose.
Probably not. It is telling you that at these inputs the system does not recover its cost within its own working life. Check three things first: that the rate is your blended rate, that self-consumption is not set unrealistically low, and that the price per watt reflects a real quote rather than a placeholder. If all three are right, the answer is the answer.
Every assumption in this calculator is argued from primary sources somewhere in our research library. These are the pages that matter for this one.
kW DC from annual kWh, peak sun hours and a derate. Not a shade-aware design.
Panel count and array area from a target kW and the datasheet wattage.
Usable kWh for backup hours and for shifting peak imports, after round-trip efficiency.
Actual results depend on roof, usage, utility rules and a real proposal. Matching is still being built. The form is an enquiry, not a dispatch line.
Written and audited by
Primary-source research, data analysis and fact checking
We are a research desk, not a sales floor. We read the statute, the tariff, the code section, the federal filing or the manufacturer data sheet ourselves, and we publish the figure with the document it came from and the date we retrieved it. Where a number cannot be traced to a primary source, we publish the shorter page and say what we could not verify. That rule has cost us whole sections, and it is the reason the rest can be trusted.
How this desk works
Data as of 6 August 2026. Authorship on this site is organisational: the analysis belongs to the desk rather than to a named individual, and we do not publish credentials we do not hold. Our editorial policy sets out how we source, date and correct what we publish.