Tagged: running costs

Most sizing arguments focus on square metres, but the wrong design temperature is the number that actually wrecks a heat pump quote.

Bigger isn't better with heat pumps. An oversized unit short-cycles, dehumidifies poorly, and costs more to run than a correctly sized one.

A heat pump hot water system typically uses a third to a quarter of the electricity of a resistance tank for the same hot water. Against gas the comparison depends entirely on your gas tariff, which is the part most calculators skip.

The honest answer is "it depends on your local gas and electricity prices" — but here's the framework for working it out for your own home, instead of trusting a marketing brochure's number.