⚡ Battery Retrofit

Home Energy Calculators

Every tool on the platform — free, no sign-up, results before any contact details. Built on EST-anchored data with methodology published.

✓ Free check✓ No obligation✓ One installer only
Facts checked against official GOV.UK sources — 27 August 2026

Diagnosis

Home Energy Funding & Savings Checker

Six questions → scored priorities → funding routes.

Start →
Heat Loss Calculator

Where your home leaks heat — roof, walls, floor, draughts.

Diagnose →
Which Upgrade First?

The right order for your property.

Sequence →

Insulation

Whole-House Insulation Calculator

Every measure your home may need, priced.

Calculate →
External Wall Insulation Calculator

£/m² and property estimate for EWI.

Calculate →
UK Insulation Price Index

The citable dataset behind every number.

View data →

Solar, Battery & Heating

Solar Savings Calculator

Generation, savings and export for your roof.

Calculate →
Solar Payback Calculator

Years to break even, honestly modelled.

Calculate →
Battery Size Guide

Match storage to your evening usage.

Size it →
Battery Retrofit Checker

Add storage to existing solar.

Check →
Heat Pump Running Costs

Your gas bill vs a heat pump, side by side.

Compare →

Two pathways

✓ If you qualify

Follow the funded route before the deadline.

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If you don’t

WH:LG, BUS, 0% VAT and one matched installer.

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AC vs DC coupling for retrofits

AC-coupled (battery has its own inverter) is the retrofit default: no rewiring of your array, works with any brand or age of system, £3,500–£6,000 installed for 5–10kWh usable. DC-coupled only makes sense if your inverter is due replacement anyway — a hybrid inverter + battery swap can be cheaper combined.

FiT and export safety

Feed-in Tariff payments are unaffected by adding storage — generation payments continue and deemed export isn’t metered down. On SEG, a battery lets you shift export into peak-price windows instead.

Sizing the retrofit

Match usable capacity to your evening consumption and summer surplus — the sizing guide has the tables. Most 4kWp homes land at 5–8kWh usable.

Yes — every tool is free, no sign-up, and shows results before any contact capture.

Indicative ranges anchored to Energy Saving Trust benchmarks (May 2026) with stated assumptions — surveys give exact figures.

The Home Energy Checker if unsure; the Heat Loss Calculator if your home feels cold; the cost calculators once you know your measure.

Sources & MethodologyVerified 27 Aug 2026

Facts checked 21 August 2026. We link to official sources and show when facts were last verified. If a scheme changes, we update the page.

Check what your home qualifies for

Free, independent, 60 seconds. We compare every option, check Government scheme eligibility and match you with one trusted local installer if you want one.

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