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Heat Pump Running Costs

  • 28-01-2023 8:49am
    Registered Users Posts: 702 ✭✭✭


    How many units/kwh per day should a Samsung/Joule heat pump and hot water system use?

    How many units/kwh would be average daily or monthly total for all electricity including heat pump?

    Our smart meter is showing we've used over 500 units over the past 12 days since the beginning of the billing cycle. Cannot fathom how we're using so much. The heat pump used 120kwh last week. We've figured out why and have brought it down to about 9 or 10 kwh per day. So there's something else causing massive energy use. We're careful and take all the usual measures, switching appliances and lights off when not using them etc.

    Could the meter be faulty?

    It's in a new build A2 rated 3 bed semi. No gas.



  • Registered Users Posts: 702 ✭✭✭gandalfio

    Took a reading yesterday at 7pm and just now at 8am and there's a difference of 10 units.

  • Registered Users Posts: 1,341 ✭✭✭Nelbert

    My heat pump pulled 132kWh last week. Mostly on night rate. A3 rated refurb.

    Do you know exactly what was on and off overnight? Do you know if the heat pump is 8 of those 10 for example?

    I think both pricing and the reporting of these modern systems has got everyone more aware of what they use which is good for monitoring but can cause you to go down perception based rabbit holes. I always remind myself "no gas bill" which in winter was significant.

  • Registered Users Posts: 118 ✭✭simpsimp

    We're in an A3 refub and the heat pump is using around 150kWh per week since start of the year, depending on external temperature.

    This will drop off precipitously once Spring takes hold.

  • Registered Users Posts: 702 ✭✭✭gandalfio

    Ok so it seems the heat pump isn't necessarily the problem if our kwhs are less than yours. Would more than 10 kwh daily on the heat pump not be considered excessive?

    What's your total kwh/units used including the heat pump? Trying to figure out how many non heat pump units are on an average bill. There's over 400 or so non heat pump units used over the past 12 days.

  • Moderators, Home & Garden Moderators Posts: 5,901 Mod ✭✭✭✭graememk

    What info can you get from the heatpump?

    Is it splitting up the amount of heat going to your Domestic hot water and the Space heating by any chance?

    400 units over 12 days, is still 33 odd kwh per day.

    Its unlikely that the meter is faulty.

    Lights/appliances on standby, especially in a new house is insignificant, Most bulbs only use a few watts, and if you had all the lights on, i dare say it still wouldnt pass 100-200w!

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  • Registered Users Posts: 702 ✭✭✭gandalfio

    I'm not sure if it's doing that or how to check. I would have thought heat pump plus electricity would be combined 10 to 15kwh per day max (600 to 900kwh or so for a 2 month bill). Otherwise its no cheaper than our old combined winter gas and electricity bills in a C rated house.

  • Registered Users Posts: 702 ✭✭✭gandalfio

    For example, 15kwh per day is 900 over 2 months. 900 at 40c per unit is €360 before VAT and standing charges.

  • Moderators, Home & Garden Moderators Posts: 5,901 Mod ✭✭✭✭graememk

    Gas is now 13-14c now per kwh, bear that in mind too, not the 4-5c of other years. so triple that gas (and possibly electric) bill! (how many kwh did the old house use in the winter bill? does the new house feel warmer/more comfortable than the old one?)

    As your in a new house, you are likely getting a good COP, say 4, So for every 4kwh of electric you are using for heat, you are getting 4kwh of heat into the house.

    10 kwh/day wouldn't be that unheard of for electric alone. never mind Water and space heating. Oven, Tumble dryer, hob, it all adds up.

    Do you get more accurate breakdown of use with the smart meter?

    Another thing to look into is a home energy monitor, which will get you a far more responsive look into your house usage (you'll be able to spot some of the big consumers of power straight away)

    As all you have right now is meter reads, you could even shorten the period of readings to an hour or 2

    eg a base load of 500w over 2 hrs will be 1kwh

  • Registered Users Posts: 702 ✭✭✭gandalfio

    Can't remember howany units in the old house, but winter gas and electricity was never more than 350 euro combined. The new house is far mor comfortable and warm than the old one.

    Smart meter only gives readings, no breakdowns.

    Yes will get a monitor and get to the bottom of things.

  • Moderators, Home & Garden Moderators Posts: 5,901 Mod ✭✭✭✭graememk

    That's my point re last years bills, Its Doubled, nearly tripled in prices. I've heard of people getting gas bills pushing €1000. Cant really compare this year with last, with the crazy rise in energy prices.

    But on the otherhand, you do have a more comfortable house now, and that still takes energy.

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  • Registered Users Posts: 1,775 ✭✭✭PowerToWait

    Like, electricity has increased by over 60% in the last 12 months alone. So a hundred quid leccy bill is now 160. Many people seem to be forgetting this.

    Everyone's electricity is stupidly expensive nowadays.

  • Registered Users Posts: 702 ✭✭✭gandalfio

    To clarify, the final bill we received in the old house was from October to December. So the unit prices are very similar to now.

    My main point is about the amount of units being used. It's way way higher in the new house.

  • Registered Users Posts: 702 ✭✭✭gandalfio

    Our combined gas and electricity from October to December was 332 euro. In a 30 year old C rated house.

    Our smart meter is showing 500 units used in the past 12 days alone. In a brand new A2 rated house.

  • Registered Users Posts: 702 ✭✭✭gandalfio

    The point of the thread was to ask people how many kwh per day is typical usage for an air to water heat pump in a new build A2 rated house. And how many daily units is typical usage for everything else.

  • Registered Users Posts: 1,775 ✭✭✭PowerToWait

    Well it depends on the size of the house, efficiency of same, external temperature, type of heating (rads or UFH), desired temperature, number of showers etc.

    My own is modest at 175 sq metres, good leak test, super insulated, UFH. 2 adults away all day.

    I used under 15 kWh some milder days this month, up to 28 kWh when drops to zero and below. House is 20 - 21 degrees 24/7.

  • Registered Users Posts: 430 ✭✭jasgrif11

    I have a Geothermal (vertical). It’s the Nibe 1240. Yesterdays usage was 25.68kWh and cost €7.59 (on Energia Ev tariff).

    Family of 5 and house 300sqM

  • Registered Users Posts: 702 ✭✭✭gandalfio

    I should mention that our house is 115sqm semi D.

  • Registered Users Posts: 1,775 ✭✭✭PowerToWait

  • Registered Users Posts: 1,775 ✭✭✭PowerToWait

    It might be worth looking into air leaks, some of these would be easy and not expensive to fix.

  • Registered Users Posts: 702 ✭✭✭gandalfio

    Any idea how many kwh per day the heat pump should be using? A2 rated, 115sqm.

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  • Registered Users Posts: 1,775 ✭✭✭PowerToWait

    Sorry, just saw this. I’ve no clue tbh, lots of variables. People on here say 15 - 20. Depends on many factors.

  • Registered Users Posts: 45,301 ✭✭✭✭Bobeagleburger

    Heat pumps seem to be an absolute drain on finances for some people.

    Demand for them must be plumetting in the era of high electricity prices.

  • Registered Users Posts: 444 ✭✭zoom_cool

    My heat pump used over the last week between 11 - 14 kwh per day for 205MSq house which is retrofitted. UFH downstairs and RAD's upstairs includes Hot water also.

  • Registered Users Posts: 110 ✭✭Scoopsire

    @zoom_cool what level of retrofit had you done? Windows, ground floors, external insulation etc?

    11-14kWh seems pretty ok

  • Registered Users Posts: 4,494 ✭✭✭jackboy

    Oil heating is still vastly superior for the majority of Irish houses. Unless your house is built or renovated by top class builders forget about heat. pumps.

  • Registered Users Posts: 444 ✭✭zoom_cool

    Triple glazed Windows, External wall Insulation 120mm, Internal wall insulation 50mm, Underfloor Insulation 150mm and I need to update attic only have 150mm Rockwool

  • Moderators, Home & Garden Moderators Posts: 5,901 Mod ✭✭✭✭graememk

    It's more like oil is vastly easier not superior. You can just get away with it and just oversize the oil boiler to make up for the losses

    Heat is heat at the end of the day be it electric/oil/gas/farts.

    Oil isn't cheap either. Currently on par with night rate electric alone, not counting the 3-4x boost the heatpump generates.

  • Registered Users Posts: 1,341 ✭✭✭Nelbert

    Heat pump costs are a lot more visible. That doesn't mean they are higher. December and January was in the region of €150 for heating and hot water each month for me. My old gas bill was multiples of that for the winter months.

    Next door neighbour spent about €250-300 for November with gas boiler. And my house is occupied all day during the week while neighbours is empty and not heating.

    Ive lost some of the net savings I'd have made if not for the price growth but I'm still measurably better off.

  • Registered Users Posts: 587 ✭✭✭theintern

    Over winter my heat pump is using between 60 and 100kwh per week. There was a higher week back in December of 140 in a week when it was really cold and below zero.

    A2, slightly larger house than yours. We keep the house warm (21 on the thermostats) all the time pretty much.

    I think it's fantastic to be honest. Similar bills to what we used to have in a smaller apartment using gas, and that's before taking into account the changes in energy prices.

    Wait till you experience the house from March onwards. According to my unit, it used basically zero electricity from March to November. So this is as high as your bills will get.

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  • Registered Users Posts: 4,494 ✭✭✭jackboy

    To get the value you are seeing you must have a well constructed well insulated house.