The Solar Decision Journey
Should I install solar on my home?
A short path from an installer quote to a payback figure based on your own location, usage and prices.
What you'll have at the end
A simple payback estimate built from your own generation, self-consumption, prices and installed cost — and a clear view of which assumption moves it most.
The Journey
- 1
Step 1 — Calculator
What system size am I comparing?
Note the system size
Take the system size in kWp from each quote. If quotes describe roof area in different units, convert them so you compare like with like.
Convert roof area→ Then continue to step 2 - 2
Step 2 — Guide
How much will this system generate where I live?
Get location-specific generation
Annual output depends on location, orientation, tilt, shading and losses. Get an estimate for your own roof (for example from PVGIS, PVWatts or the installer), not a regional average.
Read output guide→ Then continue to step 3 - 3
Step 3 — Guide
How much of it will I use myself?
Estimate self-consumption
The share you use at home depends on your generation profile, when you use electricity, storage and load shifting. Estimate it from your own usage pattern; a battery changes it, by an amount specific to your home.
Read battery guide→ Then continue to step 4 - 4
Step 4 — Calculator
What is the payback with my figures?
Calculate payback
Enter annual generation, self-consumption share, your import price, what you are paid for export and the installed cost. The calculator gives first-year saving and simple payback.
Open Payback Calculator→ Then continue to step 5 - 5
Step 5 — Guide
How do I read the payback figure?
Interpret the result
Simple payback ignores financing and future price changes. Read how it is calculated and which inputs it is most sensitive to.
Decision Summary
What you need for a solar decision
- System size (kWp) and installed cost
- Installer quotes
- Annual generation (kWh)
- Location-specific estimate for your roof
- Self-consumption share
- Your own usage pattern
- Import price and export payment
- Your bill and export terms
How to decide
Compare the simple payback with how long you expect to own the system, check how much it changes when you vary self-consumption and prices, and weigh it against other uses of the money.
Note: This site does not set a payback threshold. The result is only as reliable as the generation estimate and prices you enter.
Journey complete
You now have your own figures to decide with.
Take your results to installer quotes and revisit the calculators when your inputs change. Each calculator shows its formula and the inputs it used.
Explore more solar energy guides
Continue with another journey
Each journey below follows the same pattern: your own inputs, the right calculator, then the decision.