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Heat Pump Running Costs



  • Moderators, Home & Garden Moderators Posts: 5,899 Mod ✭✭✭✭graememk

    Pulled this out as i was dragging it off topic of a2a systems.

    If 2.5 your heat requirement (loss) would have been 225kWh, at 3 its 270kWh. How big is the house?

    Also pumps using 200w, Thats huge. to me anyway. I only have 1 circulation pump and it only uses 30 when its flat out.

    Have a look at this video, and does anything match up with your install?

  • Registered Users Posts: 1,419 ✭✭✭DC999

    As a comparison, if people want to see the surprisingly high amount of gas kWh they use you can do it easily. Check the meter on Day1. Do the same on Day2. Multiple the units used by 11.545 which converts gas in meters cubed to kWh (that conversion rate shows on your gas bill).

    The other day we used 70kWh of gas units (in a small house). ~65% of that turned into heat (20 year old gas boiler). Or €9 of gas used for a single day – which is well expensive! Ok, it was a heavier day as I ran it all day without the heating controls on to see the usage. With a heatpump we might only have needed 13kWh (it’s a small house) to generate the 45kWh of heat we needed (assuming COP of 3.5). 

  • Moderators, Home & Garden Moderators Posts: 5,899 Mod ✭✭✭✭graememk

    Yeah the gas efficiency of an old boiler surprised me, And even just doing a straight swap for a condensing one too might not even get you to 90+% if your return temperature is too high and its not going into condensing mode.

    But you could even go farther, if you arent keeping a constant temperature you can see the gas needed to get up to temperature in the first hour, and then your maintenance temperature in the next hour.

    Newer boilers can modulate down for the low and slow burn.

  • Registered Users Posts: 1,716 ✭✭✭poker--addict

    Thanks for that video, I have seen a lot of heat geek one but not that one, and mine is not dissimilar at all. Too many pumps (yes newer pumps- the ones you have- will be more like 3-50w instead of 150-250!)

    One option for me could well be to take bits out!

    my understanding is though the newer heat pump will adjust output too - so run steady at 1.5kw for example instead of on and off at 4-4.5kw. I imagine that must add double digit improvement in KW usage


  • Moderators, Home & Garden Moderators Posts: 5,899 Mod ✭✭✭✭graememk

    yeah newer pumps will adjust the pump and the compressor to maintain to say a 5c delta between flow and return.

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  • Registered Users Posts: 3,372 ✭✭✭randombar

    Hi Lads, any recommendations for apps for Ecodan.

    Was hoping to get energy usage per day and live consumption but getting very little from Melcloud apart from monthly consumption and some temps.

    Plugged into home assistant too and getting a couple of values but daily energy consumed is 0

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

    Have a look at this thread....

    I've consumption and production by DHW and CH for yesterday, current live consumption and production (the live consumption is wrong based on my shelly EM though).

    Also have a flag for defrost mode, flow temps, pump status (i.e. if it's running).

    I've used the consumption and production to see my COP although as above asterisk on the live but yesterday aligns well with shelly monitor.

  • Registered Users Posts: 781 ✭✭✭staples7

    I’ve MELCloud and find it great. Can see daily consumption. Are you sure you are using it right?

  • Registered Users Posts: 3,372 ✭✭✭randombar

    I dont think I've an energy monitor installed in my Ecodan so I can't see daily, it seems to be only an accumulation monthly.

  • Registered Users Posts: 856 ✭✭✭keno-daytrader

    Ecodan updates every day, so even though its listed monthly you can see you daily usage as the month progresses.

    ☀️ 6.72kWp ⚡2.52kWp south, ⚡4.20kWp west

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  • Registered Users Posts: 2,867 ✭✭✭dominatinMC

    Yep. And if you have an SD card, you can log all that data. Very handy system in fairness

  • Registered Users Posts: 3,372 ✭✭✭randombar

    Hi Folks,

    Any idea how I get the daily usage (through installation of an energy meter I'm guessing?)

    Installer was back to say it's a 1000 add on??

    Was wondering what needs to be installed, hardly 1000 euro.

    I know I can screen shot and take 1 day away from the last cumulative but that seems a bit mental.


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

    What brand heat pump?

    A Shelly EM or similar monitor would do the job for consumption but energy output would likely need to be gotten from the heat pump unit itself.

    The Mitsubishi WiFi connection module was thrown in for free by my installer (after a bit of moaning). They are sub 200 to buy from memory.

  • Registered Users Posts: 587 ✭✭✭theintern

    Daikin units can have a wifi card installed too, I got it for about 50 quid and installed it in about two minutes.

    And there's a HACS component that'll get the data into Home Assistant.

    Sounds like your installer gave you the 'f off I don't want to do that' quote.

    Find out the part number for your unit and you should be able to work it out.

  • Registered Users Posts: 3,372 ✭✭✭randombar

    Ecodan unit.

    Installed the wifi unit but the app isn't reporting the daily useage.

    Have the home assistant component installed but there's 0 coming back for daily usage.

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

    Oh the default HA integration doesn't give you much. There's a script / template sensors approach that gives you way more detail I think I linked to HA forum in an earlier post. If you aren't clear I can clear out my MelCloud IDs and send you a template via DM.

  • Registered Users Posts: 781 ✭✭✭staples7

    Im convinced daily data is there but you need to learn how to run a report on the app?

    Open Melcoud app> Click 'Report'> Click 'Energy Usage'> Click Name of your house Main Heating Next put in date Range - lastly click view Energy Report.

  • Registered Users Posts: 275 ✭✭Eleusis

    Would you be able to Dm this to me please? Or alternatively can someone summarise the HA integration forum linked above. Or advise where to look in it for the crucial info of getting melcloud to work well in HA? It's a long forum~ (700 posts)dunno when I would get time to read it all.

    Post edited by Eleusis on

  • Registered Users Posts: 275 ✭✭Eleusis

    220m2 renovated A3. Airtight and hrv ufh though out-1 zone. For the last year I have been running it on room temp mode cause that what installer advised. He also advised against multiple zones and instead said to play around with the valves on the manifold to control heat in the different rooms.

    In room temp mode I was getting a cop of ~ 1:4 fairly consistently, but last few weeks I have tried weather comp and am now over the last week getting 1:6 COP(sometimes more).

    Attached is my usage and delivered energy for December so far. This has temps comfortable for us 20/21 degree.

  • Registered Users Posts: 1,419 ✭✭✭DC999

    The cop is counted the other way. 3.0 means 1 unit of energy created 3 units of heat. Your graph shows a cop of 6.0 with 6 units generating 30 units of heat. For heating that is a really good COP. Way above the norm. Assuming the graphs are correct on what they show.

    What's your ufh flow temp? Must be really low for that COP. But some HPs don't like to run below a 30C flow temp I thought

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  • Registered Users Posts: 275 ✭✭Eleusis

    My WC curve isnt actually much of a curve. 25 degrees @ -4 to 22 degrees @-15

    Yes flow temp is low. Although house has BER rating of A3, I think it is actually higher than that becuase BER assessor didnt include the HRV becuase I commisioned it myself. Also an area of the building was renovated prior to him coming to assess it so he had to put it down as default to some other time I think. I didnt much care him underestimating the BER because it was still over what was requirted for heatpump grant.

    Also im not sure im quite following you. . surly 6 units generating 30 is a COP of 5? Whats the COP on atatched then? this seems to be the strongest day I had on the 8th.

  • Registered Users Posts: 1,175 ✭✭✭SharkMX

    We have oil heating and its been so mild that since the cold week recently we've only had to turn the heating on yesterday for an hour. Its been off otherwise for over a fortnight now. Very mild winter. The house is only a C BER too. Its just not very cold outside.

    Post edited by SharkMX on

  • Registered Users Posts: 781 ✭✭✭staples7

    Can you take a screenshot of your whole year view inc hot water? just interested as im ecodan with A2.

  • Registered Users Posts: 275 ✭✭Eleusis

    Sure here is for year to date. Nov is higher than it should be cause i was playing with WC curve and started way too high with flow temps. House was toasty and there was a cold spell when i was doing it.

    Whats yours out of curiosity too?

    Edit: after posting I have no idea why resolution of pics is so bad. I have attached them as files too for better resolution.

  • Registered Users Posts: 1,419 ✭✭✭DC999

    D'oh, brain can't multiple in the morning. Yes, 6 units generating 30 is a COP of 5. Which is still a great COP

  • Registered Users Posts: 845 ✭✭✭ColemanY2K

    This is the datasheet for my Thermia ITEC Eco 8kW heat pump. It has only been switched on this morning for the first time.

    35 degrees is the figure for heating the floor. I hope that this is just a reference number used to calculate the stated COP figures, energy class etc as I would like to have a lower LWT than 35. Elsewhere in the documentation it says 35 degrees is "usually" what it's set to. Perhaps that's the norm in Sweden where Thermia hail from.

    Have I got the above right or do you think I'll be stuck with a minimum 35 degree LWT?

    🌞 7.79kWp PV System. Comprised of 4.92kWp Tilting Ground Mount + 2.87kWp @ 27°, azimuth 180°, West Waterford 🌞

  • Moderators, Home & Garden Moderators Posts: 5,899 Mod ✭✭✭✭graememk

    35 and 55 (and air 7c ) is what the cop rating and efficiency ratings are based on.

  • Registered Users Posts: 845 ✭✭✭ColemanY2K

    In theory so I could improve the cop and efficiency ratings if I lowered the LWT. Hopefully that's possible.

    🌞 7.79kWp PV System. Comprised of 4.92kWp Tilting Ground Mount + 2.87kWp @ 27°, azimuth 180°, West Waterford 🌞

  • Registered Users Posts: 1,057 ✭✭✭TimHorton

    What has this got to do with Heat Pump running costs ?????

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  • Registered Users Posts: 845 ✭✭✭ColemanY2K

    If I total all these numbers up I get 3.214kWh. do I halve that number as it's half hourly or is 3.214kWh the correct figure. Yesterday the HP was turned on for first time so it'll be tomorrow or Monday before the data shows up on ESBN site but I'd like to know in advance if I'm reading things correctly.

    🌞 7.79kWp PV System. Comprised of 4.92kWp Tilting Ground Mount + 2.87kWp @ 27°, azimuth 180°, West Waterford 🌞