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Exorbitant energy Bill's due to inefficient boiler? - ASHP(Nibe f470)

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Exorbitant energy Bill's due to inefficient boiler? - ASHP(Nibe f470)

2 replies 93 views
Hi all, I'm looking for advice regarding energy Bill's I originally posted in the energy section, but I got referred here to ask if my boiler (Nibe F470) is running sub optimally. 

A rough summary is I'm living with my partner in a 2 bedroom apartment. It is fully electric with a Nibe F470 boiler ASHP.
The EPC is rated as B with very low running costs yet I'm seeing expensive energy Bill's. I am currently changing over to a cheaper tariff.

Original post:


  • Rodders53Rodders53 Forumite
    986 posts
    Tenth Anniversary 500 Posts
    ASHPs can need to run near constantly in cold weather to benefit from the Coefficient of Perfomance.  Read your way through the long - but informative - sticky threads above.  They are also best / most efficient at lower temperatures than conventional boilers.

    You don't say if you have underfloor or radiator as wet heating sources, or a mix of both?  HW can be set to a lower temperature with a 60C sterilisation session once a week to minimise any Legionella risk.  Then the ASHP will work more efficiently.

    With ASHP, the wet CH and HW system usually has a backup immersion heater that will eat electricity if allowed to be used indiscriminately and is the major problem most people have with them - especially if running the CH and/or HW water at higher temperatures.

    Search other forums for advice on this specific unit and read up about it...  e.g. looks to be interesting, and it may point you in the right direction?

    Do also get and read the installer and user manuals for the Nibe.

    AIUI these things need to be finessed to your lifestyle, and that can take time.
  • edited 29 February at 3:38PM
    matelodavematelodave Forumite
    5.9K posts
    Ninth Anniversary 1,000 Posts Name Dropper Photogenic
    edited 29 February at 3:38PM
    How long have you had the system, have you learnt how to use it properly yet. What are you considering to be exorbitant consumption, how have you got it set up, what is your flow temp, do you have it on a timer, how is it controlled?

    As Rodders says they take a bit of tweaking to suit your lifestyle and you may find that you need to adjust the settings. Trying to use a heatpump like a conventional boiler will cost you more than if you just let it idle at a low temperature for a lot longer. What sort of heating system have you got, underfloor, radiators or fan convectors.
    Ideally you need the flow temperature to be around 30-40 degrees which means that the rads will be lukewarm rather than hot, likewise don't have the hot water set above around 50 degrees otherwise the backup/boost heater will kick in and it will increase your costs.

    Dont forget that it is winter and the unit will cost more to run on colder days - try taking electricity meter readings every day (at roughly the same) to get a feel for your consumption. We only heat our hot water to 45 degrees for two hours a day and that's enough for both of us. Also make sure that you are on a decent tariff - we are on a single rate at 12p/kwh

    This is the energy profile of my heatpump during February which is heating and providing hotwater to a 140m2 detached bungalow and it's what I expect at this time of the year 2020-02-29 15.35.58.png?dl=0
    Never under estimate the power of stupid people in large numbers
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