Solar Panel Savings Estimator

This solar estimator works out yearly production as system size × peak sun hours × 365 × (1 − losses), values it at your electricity price, and divides the net system cost by the yearly savings to give a simple payback in years. It is a quick first look to compare with installers’ quotes, not a site design.

Reviewed by CostPulse HubLast updated

System and electricity

Imperial units
kW
h
A yearly average for your location.
%
Wiring, inverter, heat and dirt; 14% is a common default.
%
Lower it if exported power earns less than you pay.

Prices (optional)

per kWh
Published average: EIA 2026 forecast, STEO Oct 2026
per watt
Example price, edit to match your area
total
Only programs you have confirmed you qualify for.
Example prices: US (USD) — edit to match your area

Starting prices for the United States in USD. Fields marked “Published average” use the source below, at the date of that source. All other starting prices are example prices: round planning values, not quotes or averages. Prices change by store, area and season, so edit them to match your area. Electricity: U.S. average residential price forecast for 2026, 18.2 cents per kWh, EIA Short-Term Energy Outlook, October 2026 (source).

Your estimate

Results update as you type.

Simple payback
11.3 years
Electricity produced per year
8,475 kWh
Savings per year
$1,542.50
System cost
$17,400.00
Cost after incentives
$17,400.00
Net savings over 25 years
$21,162.61

How to use the solar savings estimator

  1. Enter the system size in kilowatts from your quote, or the size you are considering.
  2. Enter the average peak sun hours for your location; solar maps and national weather services publish them, and they are much lower in northern Europe than in the southern US or the Gulf.
  3. Keep 14% losses unless your installer gives a different figure.
  4. Lower the share at full rate if you export much of your power and are paid less for it than you pay to import.
  5. Add your electricity price, the installed cost per watt and any rebates you have confirmed you qualify for.

How the payback is worked out

Yearly output (kWh) = system kW × peak sun hours × 365 × (1 − losses %)
Yearly savings = output × price per kWh × share at full rate
Net cost = system kW × 1,000 × cost per watt − incentives
Simple payback (years) = net cost ÷ yearly savings

“Simple” means the estimate leaves out panel ageing, rising or falling electricity prices, financing costs, maintenance and inverter replacement. Installers use detailed tools that model your roof angle, direction and shading; for US sites, NREL’s free PVWatts calculator is a good second opinion.

Worked example

A 6 kW system with 4.5 peak sun hours a day, 14% system losses, all output used at home, electricity at 18.2 cents per kWh and an installed price of $2.90 per watt with no incentives:

  1. Output: 6 × 4.5 × 365 × 0.86 = 8,475 kWh a year.
  2. Savings: 8,475 kWh × $0.182 = $1,542.50 a year.
  3. Cost: 6,000 W × $2.90 = $17,400.00, so the net cost is $17,400.00.
  4. Simple payback: 11.3 years, and over 25 years the system saves $21,162.61 more than it cost, ignoring panel ageing and price changes.

Load this example into the calculator

Tips and common mistakes

  • Use local sun hours. The same system can produce nearly twice as much in a sunny desert climate as in a cloudy northern one.
  • Check how exports are paid. Net metering, net billing and export tariffs vary by utility and country, and they change the value of every kWh you do not use yourself.
  • Check incentives carefully. Programs change often. In the US, the federal residential clean energy credit (Section 25D) does not apply to installations completed after December 31, 2025, following the 2025 tax law, so confirm current state and utility programs before counting any rebate.
  • Look at the roof first. Panels last 25 years or more; if the roof needs replacing soon, do it before installation.

US, UK and Canada differences

In the US, solar quotes are usually given in dollars per watt, and the value of exported power depends on state and utility rules. In the UK, homes usually have smaller systems of around 3 to 5 kW, sun hours are lower, and exported electricity can be paid through the Smart Export Guarantee at a rate set by your supplier, usually well below the import price. In Canada, output varies strongly by province and latitude, and net metering rules are set provincially.

Metric units and other countries

Kilowatts and kilowatt-hours are universal, so no conversion is needed. In Pakistan, India and the Gulf, high sun hours make solar output strong, but tariffs, net metering rules and panel prices change frequently; type your current price per kWh and the per-watt price from local installers.

Frequently asked questions

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Results are estimates for planning only. Get written quotes from licensed contractors, check product labels, and follow your local building codes. See our disclaimer.