Solar Battery Installation Cost Calculator

How this calculator works

This calculator works in ranges rather than single figures, because real quotes, yields and tariffs genuinely vary that much. It starts from typical UK price, output and savings ranges drawn from published 2026 industry guides and official scheme documentation, then scales them by the quantities you enter and adjusts them for each choice you make below. The result is a low-to-high band that a realistic outcome is likely to fall within, not a promise of the figure you will achieve.

Home battery storage typically costs around to per kWh of capacity installed in 2026, so a 5 kWh battery lands around to and a 10 kWh unit around to . A battery lifts the share of your own solar power you actually use from roughly 45 percent to 70 to 85 percent, and paired with a cheap overnight tariff it can also store off-peak grid electricity for daytime use.

Battery capacity

Battery cost scales mainly with usable capacity in kilowatt-hours. A 5 kWh battery typically costs to installed and suits modest evening usage, while 10 to 13.5 kWh units suit family homes and households charging on cheap overnight tariffs. Larger batteries cost less per kWh, but remember you cannot fully discharge most chemistries, so usable capacity is typically 80 to 95 percent of the headline figure.

Installation type

Fitting a battery at the same time as the panels is cheaper because the electrical work, hybrid inverter and installer visit are shared, and the whole combined system qualifies for 0 percent VAT. Retrofitting later typically costs 10 to 20 percent more, since it needs a separate visit and often an AC-coupled battery or an inverter change, though retrofits can still qualify for 0 percent VAT under current rules.

Where you live

Installation labour is not priced uniformly across the UK. Published guides put London and South East installation costs roughly 15 to 25 percent above the national average, reflecting labour rates, access and parking. Hardware prices are broadly national, so the difference is mostly in the fitting.

What else affects the figures

A battery does not automatically improve payback: it raises the upfront cost, and its value depends on your evening usage, your tariff and the export rate you would otherwise earn. Batteries last roughly 10 to 15 years, so plan for at least one replacement over a 25 to 30 year solar system life. Chemistry, warranty terms measured in cycles, backup capability during power cuts, and whether the unit is DC-coupled through a hybrid inverter or AC-coupled all affect price and performance, and are worth comparing in quotes alongside the headline capacity.

Certification, planning and grid connection

Most home solar installations fall under permitted development and need no planning permission, provided panels do not protrude more than 200 millimetres from the roof plane, though listed buildings and flats have tighter rules and conservation areas restrict panels on walls fronting the highway, so check with your local planning authority if any apply. Use an MCS-certified installer: certification is required to register for Smart Export Guarantee payments and is the industry marker of a compliant installation. Your installer must also notify or seek approval from the district network operator, automatically for systems up to 3.68 kW per phase under G98 and by prior application under G99 above that. Residential solar and battery installations carry 0 percent VAT until 31 March 2027, after which the rate is due to revert to 5 percent.