Clear assumptions.
Better-informed decisions.

Start with your electricity use

Use your average monthly electricity-only bill, or enter annual kWh from your supplier. Annual kWh avoids uncertainty from direct debits and standing charges. You do not need to give your name or email to see the results.

For a monthly bill, we subtract the standing charge you enter and estimate annual usage from your unit price. If the standing charge is left at zero, it has not been deducted. A two-rate tariff uses a weighted price based on an illustrative usage pattern; it assumes the bill already reflects that tariff.

Smart meter connection is coming soon. The public calculator currently uses the bill or annual-kWh information you enter.

Your roof and system options

Google Solar supplies the nearest available building and panel configurations. We compare smaller, medium and larger layouts from those configurations. Every initial option includes a battery: 5.12 kWh for the first two layouts and 10.24 kWh for the largest.

These are example sizes, not an optimised equipment recommendation. Confirm the property shown; the building, usable roof space, shading, structure, electrical installation and grid connection all require survey checks. Where usable roof data is unavailable, we do not invent an estimate.

Before you enter electricity use, the roof cards use an illustrative 4,000 kWh/year, 28p/kWh import rate and 15p/kWh export rate. Personalising the estimate replaces the consumption and tariff assumptions with your inputs.

How we model your battery

The model follows energy into the home, battery and grid. Assumptions are 90% usable battery capacity, 90% round-trip efficiency and a 3.6 kW charging/discharging limit. The battery starts empty.

Solar generation uses the roof configuration's annual DC yield with an assumed 15% system loss. Its timing and your demand pattern are illustrative, not measured household activity or local hourly weather. The summer-day chart illustrates 21 June; it is not a forecast for tomorrow.

You can enter a cheaper off-peak tariff and explore scheduled grid charging. UK clock changes are included. Charging costs, losses and displaced solar charging affect the result, so grid charging can sometimes reduce savings. It does not count as solar self-sufficiency.

The panels-alone comparison uses exactly the same panels, consumption and tariff to show what adding the battery changes.

Whole Home Backup

You can request a backup assessment. Backup hardware and electrical works are not included in the displayed installation allowance. Whole-home coverage, simultaneous loads and operating time depend on equipment and survey findings. The savings model does not reserve battery energy for a power cut.

Savings, costs and limitations

Bill savings compare electricity costs before and after solar and storage, including export credit. Standing charges remain payable and are excluded on both sides. Enter your own tariff rates; the defaults are examples, not current supplier offers.

Unless an installer budget is explicitly shown, installation figures are example allowances: £3,500 base cost, plus £1,000 per kWp of solar and £500 per kWh of battery. They are not a quotation.

The 25-year illustration holds usage and tariffs constant, with annual panel degradation of 0.5% and battery-capacity degradation of 2%. It does not assume or guarantee that equipment will operate for 25 years without replacement.

“Savings less installation” subtracts only the initial installation allowance. Maintenance, equipment replacement, financing and discounting are excluded. The model also excludes export power limits, dynamic tariffs, battery-to-grid export and vehicle-to-grid operation. Results have not been validated against a representative set of completed installations.

How your information is used

SolarIQ is operated by GThink Ltd. For questions about your information, or requests for access, correction or deletion, contact hello@solar-iq.ai.

• Address and roof lookup: your search is processed through Ideal Postcodes and, where needed, Google geocoding. Property coordinates are sent to Google for roof and map information.
• Calculations: your electricity inputs and selected system are sent to our server to calculate the estimate. Calculating an estimate does not submit an enquiry.
• Optional email: choosing “Email my estimate” sends your name, email, property address, inputs, system choices and estimate summary to our enquiry service, Formspree. Resend handles the estimate email when email delivery is configured. This action saves an enquiry with GThink Ltd; it is not required to use the calculator.
• Service providers: Vercel hosts the calculator. Third-party map, font, chart and booking services may receive technical connection information when their resources load. Booking a call opens Calendly's separate service.
• Smart meters: the public release does not connect to n3rgy or request meter identifiers or readings.

The calculator does not save an anonymous estimate in an application database or browser local storage. Hosting logs and any enquiry or email records are separate from the displayed estimate. Closing the page does not delete a submitted enquiry; contact us to discuss its retention or request deletion.