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  • air source heat pump… talk to me.
  • flip456
    Free Member

    our aged oil fired boiler and water tank are on their last legs and with the cost of oil being what it is, I’m thinking of installing an air source heat pump. Does anyone here have any experience of them, efficency, costs to install and run etc and how would the costs compare to a new oil fired boiler and tank?

    been reading up on numerous website but any first hand info would be helpful, thanks.

    wrecker
    Free Member

    They are efficient, of that there is no doubt. BUT and it’s a big but; there is a performance tail off in cold ambient conditions (when you most need it). Some of the manufacturers offset this by using an immersion which is obviously expensive method of heating water.
    There is/was talk of using cascade systems to reach the temps required in colder conditions but last I checked this was for commercial use only (my info may be old). Mitsubishi electric make the best ones on the market (Eco Dan) IMO.
    If you want more info, drop me a PM.

    v666ern
    Free Member

    old house = no…these things work best for new builds where you can limit the amount of air leakage

    im out

    slugwash
    Free Member

    I’m also considering changing from oil when our
    current boiler needs replacing. So…

    ……Are air source heat pumps noisy?

    …..Do you have to put them near where the current boiler and heating manifold/pumps are or can you site them anywhere outside your house and run the pipework to where the boiler used to be?

    Oh, …. and I suppose you need some way of storing the hot water as I presume they don’t provide it on demand like our current oil-boiler does?

    wrecker
    Free Member

    Have a look at this for a basic idea;

    http://domesticheating.mitsubishielectric.co.uk/home/ecodan_video

    Strangely, the vid shows use with radiators which the systems aren’t ideal for due to lower temperatures compared with boiler/burner arrangements. It may be necessary to upsize your radiators.

    Smudger666
    Full Member

    Installer of ASHP here…..

    ASHP can be very efficient so long as the heat pump AND the heating system are appropriately sized.

    Chances are that you WILL need some/lots of radiator changes as well as the heat pump installation.

    In answer to the specific questions asked later….

    ASHP can go ‘anywhere’ – there is a noise so not outside a bedroom window – but most are quieter than a pressure jet oil burner so you may not feel that’s an issue. The noise is more of a vibration than the ‘roar’ of a boiler.

    If you need to run the pipework underground for any distance, the pre-insulated stuff can get reasonably expensive.

    Yes, you’ll need an ASHP-compatible hot water cylinder as you say – there aren’t any combi-heatpumps that I know of.

    I would get a local installer recommended by a manufacturer to survey the property – they should do that FOC and see what they say.

    Hope this helps

    sambob
    Free Member

    Our nearest neighbour has one, and his sounds like a flippin’ jet engine when it’s running, I’d get pretty annoyed with it if I lived next door. No idea if it’s any good.

    wonnyj
    Free Member

    They work most efficiently on a low temperature difference. so you need a well insulated house to get the best from them. Bit of a no no if you have uninsulated solid walls or a drafty house.

    Because they work on low temps you generally require a lower flow rate in the rads which means bigger pipes and radiators. Works well with underfloor in a well insulated house. Also because of the lower temps they should be turned on earlier to heat up the house over a longer time. It’s not like just firing up the boiler.

    also they do work less efficiently in very cold weather. If paying quarterly you can end up with one very big bill and 3 very small bills. So best to do a monthly direct debit.

    Using a good experienced contractor is essential. Good advice above too.

    Bear
    Free Member

    Unless you are coupling them to underfloor heating in a very well insulated and draught proofed house then no way.
    A big issue is they are mis-sold, there are many studies around showing this. I think that a lot of the renewables industry has been tarnished by companies setting themselves up as eco this, green that and pushing products that aren’t really suitable for the applications, or they inflate the savings / pay back / RHI payments.

    If you have oil and a typical house (ie not super insulated) then you could look at biomass boilers. Led to believe RHI will be good for them (again needs checking as nobody seems to be able to give a definitive answer). Also there are biomass and well designed and made biomass boilers. I have experience of one make which so far has been great. Have also installed air source which has so far been ok.

    Down side to biomass is cost, very expensive to buy, but if I had oil and needed to change then would be looking hard at it.

    boxelder
    Full Member

    We’ve had one in our ’50’s cheap build semi, with newer extension for a year. Only the extension ahs underfloor heating and we didn’t have to add/cahnge rads. the big plus is that it’s always on, running lower temps, so the house is always ambient – never too hot. Hot water temp is easy to set and water tank big, so always enough hot water, which isn’t hot enough to scald the nippers. there is a bit of noise, but as stated no worse than the oil boiler. Don’t have to remember to pay through the nose for oil refill and got rid of the ugly tank.
    Ours has an immersion for when it’s struggling. Not cheaper than oil, but no more expensive and as they’ll be giving us 40p+ for every unit of electricity our new solar panels generate, as of next week, the costs will go down, not up with time.

    flip456
    Free Member

    cheers for the info guys, i’ve arranged for a couple of quotes for the ASHP and will aslo be looking into solar panels too. looks like its going to be an expensive upgrade, hummmm 😕

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