Solar, heat pump, battery, EV — separately each is a partial answer. Together they interact: solar feeds the heat pump, the battery time-shifts cheap electricity, and the EV charges from all of it. This model runs all four calculators in parallel and shows the combined picture.
Solar + heat pump: in summer, solar generates enough electricity to run the heat pump essentially for free (hot water). In winter the overlap is smaller but still material.
Solar + battery: the battery captures daytime solar surplus for evening use, raising self-consumption from 40% to 70–80%. Without a battery, most solar exports at low SEG rates.
Solar + EV: if your EV charges during the day (working from home, or a charger on a timer), solar can directly power it — essentially free fuel.
Battery + TOU tariff: even without solar, a battery on Octopus Go shifts cheap overnight electricity into the peak — saving 15–16p per kWh shifted.
1. Insulation — always first. Every other technology performs better in a well-insulated home. Use our insulation calculator.
2. Solar — the foundation. It generates value immediately and its payback improves every time you add another technology that uses its output.
3. Battery — pairs with solar for self-consumption and with a TOU tariff for arbitrage.
4. Heat pump — biggest install, biggest disruption, but also the biggest long-term saving for homes on oil/LPG/direct electric.
5. EV — the running cost saving is real and immediate, but it's a vehicle purchase decision, not a home upgrade.
Use the official MCS register to find certified installers for solar, batteries and heat pumps in your area. MCS certification is required for SEG payments and grant eligibility.
◐ Always get at least 3 quotes · Check reviews on Trustpilot and Google
Are you an MCS-certified installer? Get listed on Knowwatt →
Researching home battery systems?
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