[fy20]

Homes that use gas in the UK typically have a gas boiler that provides both hot water for heating and domestic use (taps). They heat the water on demand, there is no facility for storing the water. Heat pumps as we have now cannot be used like that, they will slowly extract heat from the source (e.g. the air) and use it to heat up water in a buffer tank (typically a few hundred litres) - so retrofitting would mean not just replacing the boiler, but finding space for a large water tank.

A better alternative is thermal batteries, which can charge when electricity is cheap. This has actually been around for a long time in the UK as storage heaters, but now systems are coming to market that can be used to replace traditional boilers and provide hot water:

https://sunamp.com/residential/

[thedougd]

Fascinating product that I did not know existed. Am I reading the specs correctly they these only lose about 3/4 a kWh every 24hrs without energy?

[pbowyer]

I looked into Sunamp last year as they sounded idea for us when redoing our heating. They seem to have had many teething problems, including the control circuit boards having fundamental problems, and people having the battery contents expand and warp the cases.

If you're interested in going that route, have a look at https://www.google.com/search?q=sunamp+review+site:forum.bui...