Yesterday on SKY news I saw an article about a business that claims to save people good money by converting their water heating (usually done by gas in the UK) to heat pumps. This surprised me because ... let's be polite... the UK is not reporting very high temperatures at the moment, even down on the South coast. So how, right now, is a heat pump, that relies on whatever heat is present in the air, going to save anybody in the UK money?

Well... that said, I have a heat pump that manages to heat water on a winter's morning in Gauteng, when temperatures can get close to freezing.

You just need to size them correctly for the ambient temperature. Even at -20C they are still twice as efficient as a resistive heater. (I am not sure how many houses actually use gas heating - when we toured the UK 3 years ago, all the places we rented had electric boilers for central heating.)

If the heat pump is too small to heat the water at the reduced efficiency, then it falls back to resistive heating, and the efficiency really goes out the window.

2 hours ago, JustinSchoeman said:

You just need to size them correctly for the ambient temperature. Even at -20C they are still twice as efficient as a resistive heater. (I am not sure how many houses actually use gas heating - when we toured the UK 3 years ago, all the places we rented had electric boilers for central heating.)

If the heat pump is too small to heat the water at the reduced efficiency, then it falls back to resistive heating, and the efficiency really goes out the window.

Funny that not all heat pumps are equal. One wonders if they work so well why does the manufacturer provide a contact that closes at zero degrees C in order to bring in the resistive element. 

Mine uses the same power as element at 0 degrees to heat and has been for 9 years. The time is just very long at the same power. 

Edited December 19, 20222 yr by Scorp007