Ask a question

Stuck on a SCOP figure, a tariff or a sentence in a quote? Send it here. SEO-DONS LTD, which publishes this explainer, answers by email, pointing to the source that settles it.

What helps us answer

For a running-cost question, copy the electricity and gas unit rates and standing charges from a recent bill, plus any efficiency figure a quote gives. For a question about a quote, quote the line rather than attaching the document. For a question about suitability, say what kind of home it is, roughly how old, what heats it now and whether there is outdoor space.

What we cannot do

We cannot size a heat pump for a particular home, which needs a room-by-room heat-loss calculation, and we do not recommend products or firms. We can explain what the numbers in a design mean and what to ask the designer, which is often the more useful thing.

A worked example of a good question

"My quote says the heat pump has a SCOP of 4.1 at 35°C and the design flow temperature is 50°C. My electricity is 24p and gas 7p. Is the SCOP figure the right one to compare with my boiler?" That gives enough to explain why the 35°C SCOP overstates efficiency at 50°C, what figure to ask the installer for instead, and how to put it into the calculator.

Questions from people who already have one

Owners write too: radiators that feel lukewarm, a unit that steams on frosty mornings, a bill higher than the installer suggested. We can explain what is normal, such as defrost cycles and low radiator temperatures, and what is worth raising with the installer, such as a backup heater that runs often or a heating curve set too high.

Before you send

The questions page and the glossary answer many common queries in a line or two, and the calculator handles most "is it cheaper than gas?" questions directly with your own figures.