2026-05-08 · Battery · 14 min
A year with a 5 kWh battery on a small solar array
Looked at the meter data, the tariff and the bills. Payback came in a year or two earlier than expected, mostly because of the tariff.
Energy Stack
Solar, batteries, EV chargers and heat pumps. The site picks through each of these for UK houses, with rough numbers, install notes, and the questions worth asking before paying anyone to put one in.
Solar
14 guides
Battery
11 guides
EVs
9 guides
Heat
8 guides
Featured write-up
A look at the meter data after twelve months. The battery did pay back faster on a smart tariff than from solar alone, but not by as much as the original spreadsheet had assumed.
Battery · 14 minute read
Each topic has a reference page that pulls together what we have written on it.
Solar
14 guidesSolar is the layer most people start with. Hardware choices have settled down a bit, so the interesting questions are about the survey, the inverter type and the rate you get for what you send back.
Read the solar guide →
Battery
11 guidesSizing, chemistry, payback. The honest version.
EV charging
9 guidesPicking a unit, picking a tariff, getting it fitted.
Heat pumps
Built to give you a number, not a brochure figure.
/tools/solar-payback
Years to break even on a roof you describe.
/tools/battery-sizing
Smallest battery that catches your spare solar.
/tools/ev-running-cost
Smart-tariff overnight vs standard rate.
/tools/heat-loss
Sanity-check a survey figure you have been quoted.
2026-05-08 · Battery · 14 min
Looked at the meter data, the tariff and the bills. Payback came in a year or two earlier than expected, mostly because of the tariff.
2026-05-01 · Solar · 9 min
South-east at the front, north-west at the back. The decision came down to one specific bit of hardware.
2026-04-23 · EV · 11 min
A few months on the tariff. Bills before and after, what stopped being a hassle, what started being one.
2026-04-12 · Heat · 17 min
Survey, radiator changes, the BUS grant. The bit that took longest was not what we had expected.