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Heat Pump Running Costs

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  • Registered Users Posts: 717 ✭✭✭gandalfio




  • Registered Users Posts: 19,947 ✭✭✭✭Cyrus


    its in here for joule stats, i dont know for any others. i was comparing the reported temp on them versus other stats i was using

    https://foldhousing.ie/wp-content/uploads/2020/11/Heating-Instructions-Cuil-Duin.pdf



  • Registered Users Posts: 1,801 ✭✭✭hold my beer


    Mine are Heatmeiser. I must look for a manual to see if I can recalibrate.



  • Registered Users Posts: 19,947 ✭✭✭✭Cyrus




  • Registered Users Posts: 349 ✭✭andyd12


    Ok interesting. thanks for that.

    I am building a new house atm and see alot of talk on Youtube/online about people removing actuators, rooms stats etc for UFH/HP installation.

    I am in two minds whether to just install everything and remove it if not required. Afterwards it wont be possible to do the opposite



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  • Registered Users Posts: 717 ✭✭✭gandalfio


    Regarding flow temps, do these seem ok? They were input by Joule and haven't been changed.



  • Registered Users Posts: 1,009 ✭✭✭Mr Q


    It probably depends on a lot of things. But I have 30 degree max flow temp on mine, different brand. House is set below 20 though.

    Try reducing them down and see how low you can go and still be comfortable.



  • Registered Users Posts: 886 ✭✭✭ColemanY2K


    i would personally install everything…although i'm not sure how you would install UFH without manifolds. the actuators come with them.

    i might try an experiment for a couple of weeks next winter with the zones to see how it affects the efficiency of the heat pump and comfort of the home.

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



  • Registered Users Posts: 349 ✭✭andyd12


    Ye I was thinking the same.

    Ah the manifolds will have to go in. Thanks for the help



  • Registered Users Posts: 886 ✭✭✭ColemanY2K


    the ufh usually comes as a kit. i along quite a few boardsies will tell you it'll take awhile for the end-user to get a handle on the set-up. i'm only in the house since christmas and am still learning the ins and outs.

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



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  • Registered Users Posts: 99 ✭✭Alan McG


    Hi all. I'm just wondering if anyone can help me. I'm looking for an installer that would take a job in Galway to the customer's (me) specification.

    I've been looking at getting a HP installed and performed a heat loss calculation using Heatpunk, which came out at 6.4kW, a heat loss index of 1.15 and only three radiators changed. I know the exact system config that I want (which may itself be problematic for many installers).

    I approached Joule and they specified a 16kW heat pump (quoted heat loss 11.2kW) and are insisting on changing pretty much every radiator in the house to achieve a ridiculously high house temperature of 21C and air exchange (HLI 2.0). We keyep our house at 19C and have a very tight envelope. I provided my rational of why those settings aren't appropriate for me, I also provided my heat loss calculation and our annual heating oil consumption as justification as to why a smaller pump would do (I wanted 8kW), but they just fobbed me off. If I need larger radiators down the line I can have them installed as required. Their install would cost about double what my proposal would, and I'm supposed to be the customer?

    Almost every system in Ireland is either over specced and/or poorly installed as the heat loss calculation overestimates the heating requirement by 20-50%. With the right install (no buffer, direct circulation, weather compensation, no glycol) you can run a much smaller heat pump than is commonly installed, but right now I can't see how I can achieve this without an installer who's willing to push the boundaries. Any help?



  • Moderators, Home & Garden Moderators Posts: 5,991 Mod ✭✭✭✭graememk


    anyone near you on heat geek's website?

    Are you looking to get the grant too?



  • Registered Users Posts: 694 ✭✭✭conor_mc


    interested in any progress you make @Alan McG. Similar boat here, had an SEAI assessment done but the HLI requirement of 2.0 ended up dictating several tens of thousands worth of fabric improvements, but the reality is a properly designed heat pump switch for current fabric should be at least three times more energy efficient, and at the very least cost neutral to run (assuming electricity prices 3x gas prices, or thereabouts).

    I think @graememk might have a good point here though, a Heat Geek installer would be a good starting point. And potentially a properly designed non-grant install could be as economical as a grant-install.



  • Registered Users Posts: 886 ✭✭✭ColemanY2K


    i can't recommend anyone in the galway area but just FYI when i built my house last year a local plumber did the install i.e. i didn't need a specialist installer. i designed the house, ordered the kit (8kW HP) and he did the rest.

    folks would be correct in saying i paid the higher vat rate but the overall supply and install was way cheaper (multiples of thousands) than going with a specialist supplier.

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



  • Moderators, Home & Garden Moderators Posts: 5,991 Mod ✭✭✭✭graememk


    What was the technical assesment like? Was it bit like a ber? Measure rooms, windows and use more or less the default values for the age of the house? Or was it more?



  • Registered Users Posts: 1,604 ✭✭✭THE ALM


    Did Joule do the heat loss calcs?

    I also got a quote from them, supply only. I supplied them with the heat loss calcs, a list of existing rads, a floor plan and dwelling report. Our heat loss was slightly higher than yours at 6.9kW and with a higher HLI at 1.7 and they quoted for a 8kW unit.

    I used the SEAI doc for the heat loss and also used the Heatpunk and Openenergymonitor with all three giving a similar results within a few 100watts. With my calculations I reckon we could replace two radiators but as they are in the main living space which also has a pellet stove I am in no rush to replace as the additional output required is not such as large difference to have me concerned.

    I have had several quotes and most are in the 8kW heat pump size, with a couple going to 11kW. I think only one wanted to replace all the rads.

    I am waiting an actual installer to visit to discuss with my view, likes yours, to keep it as simple as possible. I know each situation is different but this seems to be the recommended way, from the likes of heat geek, to get the most out of the system.



  • Registered Users Posts: 694 ✭✭✭conor_mc


    It was a Home Energy Assessment for the SEAI grants, I was considering a one-stop shop at the time (until I saw the price tag!!). They did measure building fabric specifics (e.g. we removed vent covers to measure internal insulation) and the like, but there were some unfortunate gotcha's like we had no literature/brand for our 8-10yo composite front door so it got a default rating like a wooden door, that type of thing. They punched the numbers into an SEAI machine and produced some recommendations to hit a HLI of 2.0, which is what you need for a heat pump grant too, I believe.



  • Moderators, Home & Garden Moderators Posts: 5,991 Mod ✭✭✭✭graememk


    Yeah got that on my doors on the BER, actually had the invoice but no specifics. I know it's a damn good door Vs the previous leaky one but no cert, you got the default.

    Although the really old oil boiler was also killing the ber rating 😂



  • Registered Users Posts: 99 ✭✭Alan McG


    Thanks for all your suggestions & info. Yes, Joule did the heat loss calcs & I was hoping to get the grant. Maybe using my own plumber would be the best route, but they're like hens teeth these days and I'd also need to get an electrician and maybe a builder for the base of I didn't feel confident.

    The nearest heat geek (certified) is in Birr, Co Offaly. Looks like they work for Grant heat pumps. They have a video up online which spreads some terrible misinformation about HPs which makes me reluctant to use them, albeit this vid is a couple of years old at this stage so maybe I should give them the benefit of the doubt. I had hoped to get a homely thermostat installed which restricted my range of compatible HPs, so might have to give up on this one. Might just be worth getting them to quote from Grant anyway.



  • Registered Users Posts: 1,604 ✭✭✭THE ALM


    I did get a quote from grant, again supply only, and it wasn't the worst.

    They have a new R290 heat pump coming out in the next few months with a better smart controller so might be worth bearing in mind.



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  • Moderators, Home & Garden Moderators Posts: 5,991 Mod ✭✭✭✭graememk


    R290 ones do work well as retrofits. I'm running an ecoforest.

    I have a large buffer as a heat battery. But now have it plumbed/configured that I can run from the buffer tank or running directly. Heating the Buffer on night rate and when its empty it falls back to direct heating.

    Running it from a tado system, Have got them to set the minimum call for heat to be 30 mins too, Also have turned off the ability for a majority of rooms to call for heat. effectively setting them rooms as temperature limits.



  • Registered Users Posts: 83 ✭✭SeanieRetrofitter


    Without going through the entire thread for the answer, can anyone give a rough idea of running costs for a heat pump as a percentage of the cost of heating the same home with oil?



  • Moderators, Home & Garden Moderators Posts: 5,991 Mod ✭✭✭✭graememk


    Really depends on the install!

    But roughly a decent install should hit 3-3.5 cop at least.

    Taking that into account

    What is your current electricity rate.

    How much oil do you use in a year? And what cost per litre?

    What sort of oil boiler do you have (condensing or not, what age is it? )

    There is 10kWh of heat in a litre of oil. And depending on how efficient your oil boiler is is the amount you can capture it (could be as low as 60 or as high as 90-95%)

    You can then work out how much heat your house used in a year.

    Then you can take that kWh value and divide by 3 for a cop of 3, etc.

    Multiply that by the electric rate and you'll get how much a years heating by a heatpump would cost.



  • Registered Users Posts: 83 ✭✭SeanieRetrofitter


    Assuming an average electricity rate of 25 cents, 70% boiler efficiency, and 3.5 cop that'd save me around €350 a year.

    For me that's about 50% of my annual cost. Any ballpark quotes I've gotten for a heat pump are about €6k after the grant. So at current rates, for me it's probably only just about worth getting a heat pump when my boiler eventually dies.

    Thanks for the clear and concise explanation.



  • Registered Users Posts: 83 ✭✭SeanieRetrofitter


    Is it really necessary to replace the radiators in a house when getting a heat pump or is there a way around that that doesn't cripple the efficiency of the heat pump?

    I've read elsewhere that bigger radiators are necessary, which I'm not keen on. Partly on cost grounds, but mainly because I regardevery centimetre off wall space occupied by a radiator as a waste- it reduces options for using that wall, and i prefer flexibility. I replaced every radiator in my house with efficient and slightly over sized double panel ones partly for that reas.

    Under floor heating isn't an option- certainly not at reasonable price.



  • Registered Users Posts: 226 ✭✭curioustony


    Ok, so I use ~1600L kerosene a year
    Condensing boiler, definitely not in condensing mode, but let's go for 90%
    This is for water and heat. Don't have the Willis yet.
    1600 X 10 X 0.9 / 3 = 4800 kWh a year
    Let's say I only heat for six months, and ignore water => 27 kWh a day

    Starting with my own usage: base
    Adding the ~27 kWh / day for 6 months: base_with_hp
    Then increasing the battery from 11 to 35 kWh: base_with_hp_bat

    Unless the battery is a diy job, the repayment is going to be very long
    Until kero increases a fair bit, (it will), it is not time to change just yet -- for me

    This is only indicative as the energia plan is restricted wrt how much EV you can use in a billing period, pinergy might be better, if the battery is big enough to avoid the higher rates.
    And who knows what the leccy rates are going to do.... That's the gamble

    🌞4.55 kWp, azimuth 136°, slope 24°, 5kW, 🛢️10.9kWh, Roscommon



  • Moderators, Home & Garden Moderators Posts: 5,991 Mod ✭✭✭✭graememk


    Maybe, the lower your radiators can run the more efficient the heatpump can run. Having doubling up the the radiators you may be ok. This where design and heat loss calculations come into play.

    Firefly radiators have a table of the radiator outputs, at different delta temperatures,
    A delta 50 is a 50 c difference between room temperature and radiator temperature. usually thats a flow temperature of 70c.


    There is a conversion table at the bottom to calculate the output at lower delta temperatures. As you have already doubled up the radiators, you may be ok but would need to run the calculations.

    heatpunk is also a website where you can design a heatpump system, although you may need to do a custom wall for Irish builds as its based in the UK




  • Registered Users Posts: 2,489 ✭✭✭ECO_Mental


    Just a bit of interesting info (well I though it was..🤔)We all away fom the house for two days and let the heat pump work away. It was warm enough but no heating required but i was surprised that over the two days the HP only came on once a day for about 30mins to keep the water temp up to the setpoint (47-48deg I think)

    I though that was impressive 1.5kWh in total per day to keep it at temp. These tanks must be seriously insulated (300 litre Joule)

    6.1kWp south facing, South of Cork City



  • Registered Users Posts: 717 ✭✭✭gandalfio


    Edit

    Post edited by gandalfio on


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  • Registered Users Posts: 349 ✭✭andyd12


    I am in a similar situation with Grant for a new build.

    I have estimated heat loss at 4.8 kw.

    Grant have estimated at 6.9 kW. So, they are specifying a 10 kW HP(next model below is 6 kW). Based on my own calculations, the HP will be twice the size it needs to be.

    Nibe, Daiken all coming back with 10-12 kW heat pumps.

    I will be focusing heavily on air tightness but used 0.5ach for the calculation. What air change factor are people using for heat loss calculation?



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