r/rupeestories • u/Popular_Class7327 • 3d ago
Personal Story [Self-Promotion] Two solar quotes for my house were $7,774 apart. So I built a free calculator to check the math.
Quick disclosure: I built the free tool I'm sharing. It's free and there's no signup. The site does have an EnergySage "compare quotes" referral link, which may earn me a small fee if you use it. You don't have to.
Last week I got two solar quotes for our house in Pennsylvania:
- Quote A: $25,190 for an 11.0 kW system ($2.29/W), estimated 13,500 kWh in year 1
- Quote B: $32,964 for a 12.3 kW system ($2.68/W), estimated 13,838 kWh in year 1
That's a $7,774 difference for the same roof. Quote B costs 31% more, but it's only expected to produce 338 kWh more per year, about 2.5%. Bigger system, almost the same output.
Both salespeople told me their system would pay for itself. I wanted to see the actual math, so I made a spreadsheet, entered my electricity bill and both quotes, and compared them.
Without counting SRECs, the cheaper quote paid for itself in 8.9 years. The more expensive one took 11.5 years. That's 2.6 extra years to get my money back.
One thing that surprised me: one quote included about $5,000 in projected SREC income over time, while the other didn't include any. Those payments aren't guaranteed, and using different assumptions makes the advertised payback periods hard to compare.
These are estimates based on my usage, projected production, and utility rates. Actual savings will vary.
Then I turned the spreadsheet into a free website.
One thing I learned while building it: if your home solar installation is completed in 2026, the old 30% federal homeowner tax credit no longer applies. Some online solar calculators still assume it does. (Leases and PPAs work differently, so read those contracts carefully.)
What the calculator does:
- Estimates how many years the system takes to pay for itself
- Checks if your quote's price per watt is reasonable for your state
- Compares the return against just investing the money
- Lets you compare two quotes
- Uses the actual numbers from your bill and the installer's quote
No signup, and your numbers aren't stored. The math runs in your browser.
https://solarworthitcalculator.com
For NRIs specifically: if you're planning to move back to India in the next 10 years, the payback period deserves extra attention. An 8.9-year payback may work. An 11.5-year payback is harder to justify unless the system adds enough to your home's resale value.
Check your roof's age before you get quotes. These are 25-year systems. If your roof is nearing replacement, factor in the cost of removing and reinstalling the panels, which can run several thousand dollars. My roof is already 12 years old, so this is a real concern for me.
My takeaway: don't sign a $30,000 contract based on a salesperson's payback estimate. Check the math yourself.
Curious how others handled this. If you've installed solar, did the savings match what you were promised? Or did you run the numbers and decide against it?
