Water heater for sink

[Simon T]

OK, friend of mine (pensioner) gets his hot water in the kitchen from one of those little over-sink electric heaters which has a 7 litre tank inside and a heating element.

Problem is, it's gone kaput and needs replacing (its 18 years old, trips the RCD out and is leaking water from somewhere).

We were looking at the instantaneous water heaters, such as this one...

However, I don't think this would be up to the job as these are really meant for light hand washing.

I was therefore wondering about a compact under sink heater like this....

It won't get much use, maybe one lot of washing up per day and the occasional hand wash.

Would the under sink heater be acceptable you think, or is it a case of shelling out extra for one with a tank in?

Thanks in advance.

[The Medway Handyman]

How about

[Bill Wright]

I have a 4 litre one and it's fine. I wouldn't be without it. I have it connected to a third tap, so the hot water from the boiler is still available (but it takes a few minutes to come through hence the under sink thing). Beware, the water from these things can be dangerously hot.

Bill

[Tim Watts]

On Wednesday 08 January 2014 17:38 Simon T wrote in uk.d-i-y:

Speaking from experience (I use one to run the whole house until CH gets installed):

Do not use one of these:

Piece of crap and does not regulate the temperature. Mine failed in little over a year.

Pay a bit more and get a Stiebel Eltron - they seem well built and regulate the elctrical power and are temperature adjustable.

[Simon T]

The under sink one I was looking at doesn't have a tank.

[Bob Minchin]

A lot will depend on the electricity supply available at the sink. If it running off the ring main - maybe even a 13 amp plug, then the hot water flow with a 3kW element will be pathetically low - just about OK for a handwash but would take ages to fill a bowl for washing up. Hence the use of models with a tank. Back of envelope calcs suggest less than 1 litre per minute with input water at +10C and output at 60C

Instantaneous heaters will possibly need to be in the 8-10kW range and hefty cables to suit. Also cable upgrades will likely be part P notifiable if that sort of thing bothers you. Like for like replacement should not come under part P