PluginSolarCalculator.com

Free UK plug-in solar calculator

UK Plug-In Solar Calculator: Generation, Savings & Payback

Compare UK plug-in solar system sizes and panel setups using your postcode, panel direction, mounting angle and household electricity use. Get tailored estimates for generation, annual bill savings and payback.

Learn more about how the calculator works, or explore our full methodology.

Free, private and no sign-up

Build your plug-in solar savings estimate

Enter your postcode, plug-in solar setup and household electricity use to get an estimate tailored to your home. All calculations are private and stay in your browser.

Your location & plug-in solar setup

Your postcode, kit size, direction and angle help estimate how much electricity your kit can generate.

Enter total solar panel capacity between 300W and 1300W.
Postcode: We use PVGIS solar data to estimate how much energy panels can produce in your postcode area. Kit size: The total wattage of your solar panels. Larger kits can generate more electricity, although output may be limited by the kit’s inverter if panel capacity exceeds 800W. Kit cost: We use this to calculate your estimated payback period. Panel direction: In the UK, south-facing panels generate the most energy over the year. North-facing panels generate the least. Panel angle: Panel angle affects solar generation. Choose the option that best matches your setup: tilted for a frame or pitched roof, upright for a wall or balcony, or almost flat for a flat roof or low-angled frame.
Your household & usage

These answers help estimate how much solar you are likely to use at home.

Adults and children: Household size helps us estimate your baseline electricity use and likely appliance demand. Daytime presence: Being home during the day means more of your solar power can be used directly by your household. Working from home: Home working adds a daytime laptop and monitor load to the solar used at home estimate.
Your baseload & tariff

These details help us estimate your self-consumption and the value of the electricity your solar replaces.

Your home’s constant background electricity use from things like your fridge, Wi-Fi router and standby devices. We use 90W as a starting estimate until you add your household details; change it if you know your actual baseload.
Our default uses the current Ofgem price cap unit rate. Enter your actual daytime p/kWh rate if different.
Always-on load: Every home has some background electricity use from devices like fridges, freezers, routers and standby electronics. These devices matter because plug-in solar can feed them whenever the system is generating, even if nobody is actively using appliances. We estimate this from your household size, but you can override it if you have measured your home’s background load with a smart meter or energy monitor. Electricity rate: We use your daytime unit rate to value the grid electricity your solar replaces and calculate your estimated savings and payback period.

How it works

How this calculator works

This calculator is designed specifically for the new UK plug-in solar rules. It combines postcode-area solar data with your panel setup and household electricity use, while applying the official system limits and cautious assumptions. The result is a grounded estimate designed to reflect the generation and savings a compliant UK plug-in solar kit could realistically achieve.

Solar generation and system limits

Solar output is estimated using European Commission PVGIS data matched to the user's UK postcode area, with a 15% system-loss allowance, then adjusted for panel size, direction and angle. In line with the current UK plug-in solar rules, the calculator limits systems to four panels, 2,000W of combined panel capacity and 800VA inverter output. Where panel capacity exceeds 800W, the estimate models the inverter ceiling and associated clipping.

Solar used at home

The model first estimates household baseload (fridge, freezer, router etc), using a conservative household-size estimate unless you enter your own figure. It then works out how much estimated solar generation is likely to cover that baseload, and how much spare solar may be used based on daytime presence and work-from-home patterns. Battery storage is not modelled, in line with the current UK plug-in solar rules.

Savings and payback

Savings count only the solar electricity estimated to be used in the home. Export income is not assumed because eligibility for UK plug-in solar systems has not yet been confirmed. Payback is based on the selected kit cost and electricity rate, defaulting to the current Ofgem price-cap unit rate where no custom tariff is entered. Longer-term savings include a 0.4% annual panel degradation allowance after year one to simulate panel ageing.

Daily availability

The hourly chart illustrates how much power the selected kit could produce on a typical clear day in each season, using regional PVGIS profile data. It is not a weather forecast, but it helps show likely peak generation windows, how solar availability changes from winter to summer, and how much output may be absorbed by your household baseload during the day.

Disclaimer:

We aim to keep the estimates realistic rather than optimistic, but real-world results can still vary with weather, shade, mounting quality, panel specification, inverter performance, appliance timing and how much electricity is used while panels are generating.

Explore the full detail behind our calculator modelling on our methodology and assumptions page.

Tips & guides

Helpful plug-in solar guides

Practical guides to help you understand plug-in solar generation, setup choices and likely savings.

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