What Is PV Yield? A Free Solar ROI Calculator, Explained
PV Yield is a free, browser-based solar return calculator. You enter your location, system size, installed cost, and electricity tariff, and it models 25 to 30 years of cashflow to show payback, IRR, NPV, and LCOE before you commit capital.
What PV Yield actually does
PV Yield turns a short list of project inputs into a full financial screening for a rooftop, commercial, or ground-mount photovoltaic project. It is not a quoting tool and it does not sell hardware. It is an early-stage model you use to test whether a proposal is plausible, compare two scenarios, and sanity-check an installer's numbers.
The core outputs are:
- Payback period — the year cumulative net cashflow turns positive.
- IRR — the annualized return, useful for comparing solar against other uses of capital.
- NPV — lifetime value created in today's money after discounting.
- LCOE — the cost per kilowatt-hour the system produces, for comparing against your retail tariff.
- Sensitivity — how much the result moves when cost, tariff, or irradiation change.
How the calculation works
The model runs in five steps. First, it resolves local weather using PVGIS or NASA POWER satellite data, or a coordinate you provide. Second, it converts system size and installed cost per watt into a nominal investment. Third, it applies module degradation, a set of system losses, and a self-consumption ratio to estimate annual energy and revenue. Fourth, it builds a year-by-year cashflow that subtracts operating cost, loan payments, and tax. Fifth, it derives payback, IRR, NPV, and LCOE from that cashflow.
None of this requires an account. Inputs stay in your browser, and you can export the result to Excel or share a link with your assumptions embedded.
What you need to enter
| Input group | Examples | Why it matters |
|---|---|---|
| Location and weather | Country, city, or lat/lng; PVGIS or NASA POWER | Drives annual generation, the single biggest driver of value. |
| System size and cost | Roof area or capacity in kWp; EPC cost per watt | Cost per watt is usually the assumption that moves payback most. |
| Tariffs | Self-consumption rate; retail and export tariffs | Self-consumed energy offsets expensive grid power; export earns less. |
| Finance and lifetime | Loan ratio and rate; discount rate; project years | Changes the shape and timing of net cashflow. |
Who PV Yield is for
- Homeowners comparing "is solar worth it?" against bank savings or another investment.
- Small businesses screening a rooftop or carport system before talking to installers.
- Installers who want a fast, neutral second estimate to show a prospect.
- Researchers and students who need transparent formulas rather than a black box.
What PV Yield is not
This is the part most calculator marketing skips. PV Yield is an early screening model, not engineering design. It does not perform a shading survey, structural assessment, or grid-connection study. It uses typical loss and degradation assumptions that you should replace with project-specific values. It is also not tax, legal, or financial advice — real projects depend on local policy, equipment choices, and your actual utility contract.
A model that says "12% IRR" is only as good as its inputs. If you feed it a module-only price instead of a full turnkey cost, or a retail tariff instead of your real export compensation, the headline number will be optimistic.
How it compares to an installer quote
An installer quote is a commitment backed by site-specific engineering. PV Yield is the opposite: a fast, editable estimate you use to pressure-test that quote. The right workflow is to enter the installer's own numbers into the calculator, then see whether the payback and IRR they promise survive a conservative scenario. If the quote only looks good under best-case assumptions, that is a signal to ask harder questions.
Where to go next
Start with the calculator, then read the methodology page for the full calculation framework. The guides below explain each output in plain language and show which assumptions move the result most.
PV Yield is free and requires no signup. It is an educational screening tool, not a substitute for installer quotes, engineering design, or professional financial advice. Always verify local tariffs, incentives, and policy before making a purchase decision.
Frequently asked questions
What is PV Yield?
PV Yield is a free, browser-based solar ROI calculator. You enter location, system size, installed cost, and tariff, and it models 25 to 30 years of cashflow to show payback, IRR, NPV, and LCOE.
Is PV Yield free and does it need signup?
Yes. It is free, requires no account, and runs entirely in your browser. You can export results to Excel or share a link with your assumptions.
How accurate is the PV Yield calculator?
It is an early screening model, typically within 10 to 20 percent of detailed engineering. Accuracy depends most on turnkey cost per watt, self-consumption ratio, and your real tariff.
Does PV Yield replace an installer quote?
No. It is a fast, editable estimate to pressure-test a quote, not a substitute for site surveys, engineering design, or professional advice.