Undersink electric water heater

I would have said there are quite a few on the market.

Having it gravity fed means there is no need for a vent or expansion vessel so virtually any model of undersink water heater will be ok.

I got mine second hand from ebay, but the likely suspects also do them, Screwfix, TLC etc.

Most come well insulated, obviously the smaller the volume, the less the surface area to lose heat.

But the faster it?ll cool down as its surface area to volume ratio is bigger. Whether that matters in practice is another matter and will depend a lot on your usage pattern.

Tim

Mike posted

We're in the same position and fitted a Elson 10/15L Unvented Water Heater (Model EUV15). We connected it to the hot water rather than cold water supply, because our problem was that the long pipe run to the kitchen caused a long wait for hot water from the main HW tank. It works very well.

These are device that are generally permanently plugged in, so the temperature is always maintained.

The volume required is more down to the type of use its put to.

Screwfix do a 15 litre unvented unit