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A2W Heat Pump Setup

  • 21-04-2020 12:53pm
    Registered Users Posts: 39 McOptimist

    Hi - I bought a new build house last year which is A2 rated and it has a air-to-water heat pump. My electricity bills are a lot higher than expected. I would like to get someone with experience to check the setup of my heat pump to ensure it is operating correctly. I am based in Dublin, if anyone could recommend someone to help here either on thread or via PM that would be great. Thanks.

    Also, if there is any analysis I can do myself in terms of recording information that would be helpful that would be great too.


  • Registered Users Posts: 10,926 ✭✭✭✭ Calahonda52

    What bills did you expect?

    Did you have a reference point?

    How much hot water are you using?

    What you can do is take a meter reading every night before the last person goes to bed and first thing in the morning, before anyone gets into the ely shower etc.
    I assume you have a day/night meter so read both
    This will give you a good stab at what the heat pump is drawing, assuming it is running at night.

    If it is say a 24kW output HP and say it's on for 8 hours at night
    then it will draw about 7 to 8 kW, say 7.5 from the grid based on a COP of 3, and say a load factor of 80%
    7.5 by 8 by 0.8= 48 kWh
    7.5 by 8 by 0.5= 30 kWh
    and so on for different load factors: ie the % of time it is running.

    For more accuracy you can strip out the fridge freezers etc but for now no need.

    Do that for a week and report back please with the daily numbers and some idea of the house size as well say spec you can get from the nameplate on the HP.

  • Registered Users Posts: 3,292 ✭✭✭ 0lddog

  • Registered Users Posts: 39 McOptimist

    Thanks! I will have a read through, collect some numbers and report back.

  • Registered Users Posts: 83 ✭✭ hero25

    Ive an A2 house, 320sqm... in it ~4 years. The control unit tells me how many hours its been running and how many hours have been used for heat and how many for hot water. Ive been tracking this for the last ~3 years and have posted a link to usage below.
    I think the hours run can be used with the HeatPump Power/KW to determine units used etc, if i was so inclined!
    Bottom line is, for all Electricity usage in the house - I've been using ~13,200 units per annum for each of the last 3 years.
    Gives me an annual Electricity bill of ~ 2300euro. I'm not sure if it should be lower, but I do have 4 x teenagers and all they bring in terms of energy efficiency....
    Overall we're happy with that costs. Hope this helps you get some clarity on your costs....