The archive
Long-form essays. We show our working and update conclusions when the evidence moves.
Battery · 14 min
A 4 kWp roof in Surrey, a 5 kWh battery and a year of half-hourly meter data.
Solar · 9 min
A 2.8 kWp system was the sensible number in 2019. It is not now.
EV · 11 min
Three differences that matter, seven that the marketing wants you to weight.
Heat pumps · 17 min
A semi in West Yorkshire. The 14 kW survey was wrong.
Battery · 6 min
The vehicle-to-home story keeps getting closer. We tally what is shipping.
Tariffs · 8 min
The cheapest unit rate is not the cheapest tariff.