Articles

Twelve topics, each answering one question with numbers rather than adjectives.

Heat pump vs gas boiler: the running-cost maths for 2026

At the July 2026 Ofgem cap, electricity is 3.56 times the price of gas per kWh. That single ratio decides whether a heat pump is cheaper to run than a condensing boiler.

Why your installer's SCOP number is optimistic — and what to use instead

Datasheet SCOP is measured at 35 °C flow in a laboratory. Your house is not a laboratory. Here is how to convert a quoted SCOP into something you can put in a spreadsheet

Do you need new radiators for a heat pump? (usually not, here's why)

The standard claim is that a heat pump means replacing every radiator. In most houses it means replacing three or four. Here is how to work out which ones, and what it bu

Heat pump in a 1930s semi with no cavity insulation: real numbers

The most common British house in the most common condition. Full calculation: heat demand, flow temperature, SCOP, running cost against gas, and what changes if you fill

What happens to your bills if gas prices fall 30 %?

The stress test nobody selling heat pumps runs. If gas drops 30 % and electricity stays put, what happens to your running cost and your payback?

MCS, SCOP, COP, flow temperature: the five terms that decide your bill

Five pieces of jargon do all the work in a heat pump quote. Understand these and you can read any quote in the country; miss them and you are comparing prices with no ide