Solar & home energy FAQ

An estimated £6,000–£8,000 for a typical 4kW system installed (MCS data: ~£1,565–£1,686/kW), or £10,000–£14,000 with a 5kWh battery. 0% VAT applies until 31 March 2027. Get your range from the solar cost calculator.

For a decent south-facing roof with someone home in the day: yes, an estimated 10–15 year payback at the October 2026 cap of 26.32p/kWh, then years of low-cost power. North-facing, heavily shaded, or moving soon: probably not. The full honest version is our worth-it guide.

Divide your annual usage by ~850 (estimated UK yield per kWp). A typical home using 2,900kWh needs about 3.4kWp — roughly 8 modern 430W panels. The panels calculator adjusts for your roof direction and shading.

SEG pays you for solar electricity exported to the grid. October 2026 standalone rates: E.ON Next 6p, ScottishPower 6p, So Energy 4.5p, Octopus 4.1p, OVO 4p, British Gas 3p per kWh — or 12–16p/kWh on combined import deals. You need an MCS certificate and a smart meter. Estimate your income with the SEG calculator.

The Boiler Upgrade Scheme gives £7,500 off air-to-water or ground source heat pumps in England and Wales (£9,000 for off-gas-grid oil/LPG replacements in the 21 Jul 2026 – 31 Mar 2027 window; £2,500 air-to-air; £5,000 biomass), via an MCS installer, running to 2030. No EPC required since April 2026. Model it in the heat pump calculator.

31 December 2026. ECO4 funds insulation and heating upgrades for eligible low-income households. Its successor, the Warm Homes: Local Grant, runs to March 2028 via local councils. Check eligibility in the grant checker — if you qualify for ECO4, don’t wait.

No. Residential solar, battery and heat pump installs are 0% VAT until 31 March 2027, as is insulation. Domestic electricity bills are also 0% VAT from 1 October 2026 to 31 March 2027.

Upfront: similar, once the £7,500 grant is off the heat pump and a combi swap (£2,000–£3,500 estimate) is compared fairly. Running: at 26.32p electricity vs 7.97p gas, a SCOP-3.0 heat pump roughly matches a 90%-efficient boiler. Carbon: the heat pump wins clearly. Compare in the running-cost calculator.

25-year performance warranties are standard; degradation is ~0.5%/year (estimate), so panels generate usefully for 25–30+ years. The inverter typically needs one replacement at 10–15 years (estimated £800–£1,500). Full breakdown in the lifespan guide.

Yes, at reduced output — roughly three-quarters of annual generation lands April–September. Annual totals are what matter for payback, and the UK estimate of ~850kWh/kWp/year already includes British weather. Details in how solar panels work.

Usually: loft insulation to 270mm and cavity wall filling are the biggest cheap wins, often a full band for under £1,000 combined. The EPC estimator ranks improvements for your home — but only an accredited assessment produces a real rating.

No. We’re an independent calculator site — no installer commissions, no sponsored rankings. Read about how our figures are checked.