Commercial & small business

Commercial solar payback calculator

Enter your system cost, electricity rate, and incentives. Get a simple payback period plus a 25-year savings total, factoring in the federal ITC, any rebate, and rising electricity rates.

Your numbers

1 Project details Optional
Shown on your exported report. Leave blank to skip.
2 Your system
From your installer's proposal, or use the system size by square footage tool.
US commercial systems typically run $1.10 to $1.80 per watt before incentives.
Check NREL's PVWatts for your exact address.
Accounts for inverter loss, wiring loss, dust, and temperature derate combined.
3 Costs and rates
Your blended commercial rate, from a recent utility bill.
US and Canadian utility rates typically rise 2% to 4% a year.
Cleaning, monitoring, and inverter service. Leave blank if unsure.
4 Incentives
Check the commercial ITC calculator if you're unsure which bracket applies.
A flat rebate amount, if your state or utility offers one.

How it works

Three steps to a payback number

Step 1

Get your installed cost per watt

Pull this from an installer's proposal, or use $1.10 to $1.80 per watt as a planning range. If you don't have a system size yet, run the system size by square footage tool first.

Step 2

Enter your electricity rate and incentives

Use your blended commercial rate from a recent bill, plus a modest annual escalation. Confirm your ITC bracket with the ITC calculator if you're stacking any bonus adders.

Step 3

Check the result against depreciation

This tool's payback period doesn't include MACRS. Run the MACRS depreciation calculator next to see how much faster your real, after-tax payback lands.

Understanding your payback period

What this number actually measures

Payback period is how long it takes your electricity savings to repay the net cost of the system after incentives. Most commercial systems land between 4 and 8 years once the federal ITC is applied, versus 8 to 12 years on the raw cash price alone. A system with a shorter payback frees up cash for other business investments sooner.

Why the net cost matters more than the sticker price

The installed cost per watt only tells half the story. Once you subtract the 30% ITC and any state or utility rebate, the amount you're actually recovering through savings is often 30% to 45% lower than the sticker price. The ITC calculator breaks this down on its own if you want to isolate just the tax credit piece, and the Department of Energy's guide to going solar outlines the broader cost and savings factors this net figure is built from.

Why rate escalation shortens payback

Electricity rates for US and Canadian commercial customers have risen 2% to 4% a year on average over the past decade, though the EIA's own analysis of retail electricity price trends shows real increases running as high as 2.6% to 2.8% annually in states like California and across New England. Since your system's production stays roughly flat while the value of each kWh it offsets keeps rising, a rate escalation assumption makes your real payback shorter than a flat-rate calculation shows. Skipping this input understates your savings.

What this tool leaves out

This calculator doesn't include MACRS or bonus depreciation, since those depend on your business's specific tax bracket and filing situation. It also holds O&M cost flat rather than escalating it, and it doesn't model panel degradation, which typically reduces output by about 0.5% a year. For financing-specific comparisons, see the loan vs. cash comparison or PPA vs. ownership tool, and the 25-year degradation curve tool to see how that annual production loss compounds over the life of the system. A commercial roof has its own costs and limits. The roof replacement cost calculator in our Solar + Roofing Integration section can help you check whether your roof is ready before you commit to a size.

What to do with this number next

Once you have a payback period, run the ROI calculator and NPV calculator to see the same system from a return-on-investment angle instead of a break-even angle. Both use the same inputs you already entered here, and the 25-year lifetime savings calculator in our savings and payback section covers the same math from a residential-scale angle. A size estimate is only half the decision for a business. The cash purchase vs financed payback comparison in our Financing section can help you work out which way to pay for the system costs less.

Questions

Frequently asked

Most commercial systems pay back in 4 to 8 years after the federal ITC. A 150 kW system costing $240,000, with a 30% ITC and a $5,000 rebate, nets out to about $163,000 and pays back in roughly 6.9 years at an $0.11 per kWh electricity rate.

Yes. The 30% federal Investment Tax Credit applies to the full installed cost of a commercial solar system, including equipment and labor, before any state or utility rebate is subtracted.

Use your current rate as the baseline, then add a modest annual escalation, typically 2% to 4% for most US and Canadian utilities. A rate that rises over time shortens your real payback period compared to using a flat rate for all 25 years.

No, this tool covers the ITC, rebates, and electricity savings only. Run your numbers through the MACRS depreciation schedule calculator separately, since depreciation savings depend on your business's tax bracket and typically shave another 1 to 2 years off payback.

Related tools

Keep evaluating this system

Commercial solar ROI calculator Commercial solar NPV calculator Commercial ITC calculator MACRS depreciation schedule calculator Commercial loan vs. cash comparison Commercial PPA vs. ownership Commercial solar 25-year TCO calculator All commercial tools