Best 'Under sink' heater

Discussion in 'Plumbing and Central Heating' started by Furkin, 3 Apr 2021.

  1. Furkin

    Furkin

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    Hi guys,
    When I say 'best', I mean value for money,,,, or even entry level.
    I'm putting a new sink in the kitchen and ant to do away with the Heatrae on the wall.
    The sink will be a narrower one due to kitchen size.
    Its a small bungalow, with just me - :(.
    Basically, it's just for the dishes and thinks like that.
    As usual, there are tons out there, and features and things will have moved on a pace since I last looked at this sort of thing.
    I don't want to spend a fortune, but I don't want to buy carp :sneaky:.

    I'd love comments from you guys please.

    I hope you are all keeping well and safe.

    Baz
     
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  3. oldbutnotdead

    oldbutnotdead

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    Are you bothered about the sink filling slowly? (about 2 minutes for 10 litres hot enough for washing-up). And has your cu got capacity for another 40a breaker and can you get 6mm or 10mm cable to undersink? 65189 from Toolstation will do you, you get to choose your own taps as well
     
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  4. Furkin

    Furkin

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    many thanks OBND
    Damn - I knew it wouldn't be easy !
    I'm due to get a new small CU, so that wouldn't be a problem, but I have just tiled the walls (not realising that I would want to get rid of the heatrae), so bigger cable is out.
    Do they all need that size breaker/cable ? I know that showers and cookers etc do.
    That may be a quick result - but not the one I wanted.

    I have now been looking at hot water taps. One of these might suit, many of which either plug in or wired to the basic ring-main.

    Anyone with experience with these please ?
     
    Last edited: 3 Apr 2021
  5. oldbutnotdead

    oldbutnotdead

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    You can get 3kw flash heaters (so will run off an rfc or radial) but you're looking at 6 plus minutes for enough hot to wash the dishes. If you can run pipework back from undersink to somewhere you can get power to that would work (the flash heaters are unvented so cld be remote from the sink).
    EDIT You can get unvented tank types that require far less current but once you've used the stored hot you've got a 15-20 minute wait for reheat. Plus there's a running cost to keep stored water hot- not massive but noticeable.
     
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  7. Furkin

    Furkin

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    At the moment, I turn the Heatrae on when I need hot water (I think) about a gallon - more than a kettle full (2Kw). I then have to wait for about 10 mins for a full re-heat, or sometimes I may run it off at half heat to top up dishes, so waiting for a re-heat shouldn't be a problem.
    I only wash dishes once a day. Once in a blue moon, I'll need hot for something else.
    As long as I get enough for the dishes in one go, should suffice.

    Are these something like what I should be looking for:
    https://www.amazon.co.uk/dp/B01MPYD...uPWNsaWNrUmVkaXJlY3QmZG9Ob3RMb2dDbGljaz10cnVl


    https://www.amazon.co.uk/Speedflow-...d3845234c841195db5a9b72237c0d7&language=en_GB


    The Speedflow mentions 1.5 cable, which seems a bit small ?


    What is the highest wattage that can be used from a 13amp socket – as far as a heater is concerned ?
     
    Last edited: 4 Apr 2021
  8. denso13

    denso13

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    3kW is the maximum.

    That's the cable length, 1.5m.
     
  9. JohnD

    JohnD

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    Your amazon links don't work for me. What make and model are you looking at?

    A 3kW heater can heat about 1 litre of water per minute. Less in winter when it starts colder, and there is an additional delay as the metal tank has to be warmed.

    The thermostat will turn off the power once it is up to temp. If it is reasonably modern and well insulated the heat losses will be insignificant even if you leave it turned on, unless the tap is dripping. Ten minutes at 3kW uses about 8p worth of electricity. I'd reckon on about 10 litres to wash up a modest amount.

    If you are forgetful you can use a switch with an integral timer that turns off after 30 minutes (or an hour, or whatever) which is handy in church halls and similar places.

    If you look at the dimensions or makers label on yours you can probably find its capacity. The difference in cost between a 5l, 10l and 15l heater is very small.
    https://www.tlc-direct.co.uk/Main_I...ex/Under_Sink_Water_Heaters_Vented/index.html

    But surely you have a bathroom with running hot water?
     
  10. Furkin

    Furkin

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    Thanks guys,

    Dougal: cooo,,, I wish I could read !! Thanks mate.


    JohnD: Some good reading there thanks.
    The links refer to:

    a/ Ariston Andris Lux Undersink Water Heater 2 Kw, 15 L

    b/ Speedflow Unvented Undersink Water Heater 15 Liter Capacity.

    It was just to give an idea of the sort of thing I’m looking at – as long as they are useable and legal.

    Now I know I can go up to 3kw, will add items to my viewing pleasure.


    But surely you have a bathroom with running hot water?
    Why ‘surely’ ?
     
    Last edited: 7 Apr 2021
  11. DIYnot Local

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