Advertisement
If you have a new account but are having problems posting or verifying your account, please email us on hello@boards.ie for help. Thanks :)
Hello all! Please ensure that you are posting a new thread or question in the appropriate forum. The Feedback forum is overwhelmed with questions that are having to be moved elsewhere. If you need help to verify your account contact hello@boards.ie

New Build, 7 months in with a Danfoss heatpump

Options
245

Comments

  • Options
    #32
    KCross
    Registered Users Posts: 12,094 ✭✭✭✭KCross


    murphaph wrote: »
    I leave the HP on permanently during the heating season. This topic gets debated to death on German forums and there is never a clear winner where the house is "well insulated with UFH", so I just go for the most comfortable option which is (for us) constant temps throughout the house.
    matrat wrote: »
    I am also always surprised to hear people turn off their machines in the summer. I do not know of any way to heat all domestic water cheaper than the unit does when you include total cost.

    I dont have a Danfoss (I have a Nibe) but the technology I suspect is identical and in the Nibe it automatically turns itself "off" when the average outside temp over a 24hr period goes above a set figure(which you can change). I hear people saying they turn off their units but they dont need to. The outside temp will cause it to happen automatically anyway.

    It obviously still heats the water every day but it stops the space heating.

    Does the Danfoss not do the same?


  • Options
    #33
    matrat
    Registered Users Posts: 152 ✭✭matrat


    @Water John
    I agree 100%, but wearing shorts in winter is easier than listening to a cold irish wife. And sleeping with just a sheet in the middle of winter sometimes leads to slight rewards!! I suspect its one of those first world problems!!

    @KCross
    Yeah the Danfoss does exactly the same. My log shows that there was some weeks in the summer when the heating circuit on the machine wasnt on at all, while the domestic water circuit did its usual 8-10 hours in the week to meet all the domestic water needs. The Danfoss has a heat stop setting also same as you, mine is set to 17 deg, once outside temp is at that then no heat can be supplied to the house, but naturally domestic water is still reviewed and keep heated as necessary.


  • Options
    #34
    KCross
    Registered Users Posts: 12,094 ✭✭✭✭KCross


    matrat wrote: »
    @Water John
    I agree 100%, but wearing shorts in winter is easier than listening to a cold irish wife. And sleeping with just a sheet in the middle of winter sometimes leads to slight rewards!! I suspect its one of those first world problems!!

    @KCross
    Yeah the Danfoss does exactly the same. My log shows that there was some weeks in the summer when the heating circuit on the machine wasnt on at all, while the domestic water circuit did its usual 8-10 hours in the week to meet all the domestic water needs. The Danfoss has a heat stop setting also same as you, mine is set to 17 deg, once outside temp is at that then no heat can be supplied to the house, but naturally domestic water is still reviewed and keep heated as necessary.

    The Nibe uses a 24hr average rather than a straight "max outdoor temp". Mine is set to something like 13C. So, over a 24hr period if the average is above that it shuts off.

    So, it sounds similar which proves the whole "turn it off in the summer" is just a waste of effort. The system will do it itself. These really are plug n play systems. Once you get them set to your desired comfort levels you shouldnt need to touch it again... that does take a few winter/summer cycles to get it right but once you have it and the wife is happy!... just let it do its thing.


  • Options
    #35
    murphaph
    Registered Users Posts: 19,018 ✭✭✭✭murphaph


    Yeah there's no way we can or would want to switch ours off either as it produces hot water very economically, especially in summer as the air temps are much higher.

    I do plan in the future to fit photovoltaic (roof is 100m² at 45° facing SSW) and when that happens we'll modify how we run the heat pump to charge up the UFH and DHW in the afternoon.


  • Options
    #36
    BarneyMc
    Registered Users Posts: 1,504 ✭✭✭BarneyMc


    murphaph wrote: »
    I leave the HP on permanently during the heating season. This topic gets debated to death on German forums and there is never a clear winner where the house is "well insulated with UFH", so I just go for the most comfortable option which is (for us) constant temps throughout the house.

    Is there cheap night rate rates there? If so even with this it's not guaranteed to save by powering the HP at night?


  • Advertisement
  • Options
    #37
    Water John
    Registered Users Posts: 21,171 ✭✭✭✭Water John


    Barney, with a good well sealed, high insulation build, the actual amount of heat needed in an Irish situation is quite low. 4/500 euro per year.
    You could put in a large storage tank to benefit from night rate but the upside is only a few hundred euro. Is it worth the extra capital cost?
    A continental house with a colder winter would give a different answer.


  • Options
    #38
    murphaph
    Registered Users Posts: 19,018 ✭✭✭✭murphaph


    BarneyMc wrote: »
    Is there cheap night rate rates there? If so even with this it's not guaranteed to save by powering the HP at night?
    No night rate electricity here. There is a "heat pump" tariff which necessitates a second dedicated meter with its own standing charge. The discount on the unit rate gets mostly eaten up by the standing charge in a modern build as the actual costs to run the heat pump aren't that great to begin with. The heat pump meter is also controlled by radio by the network operator and can be shut off up to 3 times per day for a certain amount of time (during peak hours mostly).


  • Options
    #39
    BarneyMc
    Registered Users Posts: 1,504 ✭✭✭BarneyMc


    Water John wrote: »
    Barney, with a good well sealed, high insulation build, the actual amount of heat needed in an Irish situation is quite low. 4/500 euro per year.
    You could put in a large storage tank to benefit from night rate but the upside is only a few hundred euro. Is it worth the extra capital cost?
    A continental house with a colder winter would give a different answer.

    I'm currently running it at night and it's working out fine. I'm just knocking off the UFH by knocking off the room stats (if I decide to do this long term I'll change the setting on the HP). So when I get up in the morning I knock it off and then turn the room stats on last thing at night. The GF room stats at set at 22C and they only drop to 21C (some stay at 22C).

    I suppose this has been all tried and tested to death and just wonder what I'm really saving doing all of this, i.e. making the most of the night tariff as opposed to keeping the HP on full time and making the most of daytime temps and a more balanced heating regime. If it really only saves even €100 a year (perhaps not even) then I suppose it's not really worth it. Final BER has not been produced yet but I'm almost passive.


  • Options
    #40
    tobdom
    Registered Users Posts: 511 ✭✭✭tobdom


    matrat wrote: »
    Hi all,

    Hope this helps making someones decision easier and any questions please let me know!!

    Very interesting discussion folks, I'm grateful for it. We're currently awaiting word back on our mortgage to see if we can proceed with our build (in Co. Galway) as it is currently designed & costed - already have planning for it. Had it costed a little under 2 years ago and the revised costing (very detailed) just back from the QS is +20% :eek: based on current market rates...

    Almost everything has gone up significantly, particularly labour and most materials. Anyway, I've been adamant from the outset that we'd go with an A2W HP system with UFH. Our costing though is for oil + 8m2 solar with either UFH or rads (costed the same). So I think roughly, we'd be looking at +3-5k to have a2w instead. It's not a decision I want to make on cost alone, if cost wasn't an issue I'd be going with a2w HP with UF, but unfortunately cost has to be a major consideration.

    Anyway, this has been a good read and thanks for everyone's input on this thread.

    @matrat, I sent you a PM in relation to the info you shared. If you'd be good enough to share some supplier details etc. via PM that would be much appreciated.


  • Options
    #41
    Water John
    Registered Users Posts: 21,171 ✭✭✭✭Water John


    The solar would have a particularly poor ROI. HP is the way to go.
    Well sealed and good insulation.


  • Advertisement
  • Options
    #42
    murphaph
    Registered Users Posts: 19,018 ✭✭✭✭murphaph


    If you end up fitting oil then still go ahead with the UFH if you want to leave yourself the option of a heat pump in the future but make sure the pipe spacing is tight enough to support a low flow temp system (heat pump). You can't re-lay the UFH later. If the pipes are spaced at like 300mm centres you can forget running the UFH with low flow temps!


  • Options
    #43
    rolion
    Closed Accounts Posts: 3,362 ✭✭✭rolion


    Water John wrote: »
    The solar would have a particularly poor ROI. HP is the way to go.
    Well sealed and good insulation.

    Let's agree to disagree please.

    Solar does makes sense.Both, PV and tubes, if they are well designed and used.
    Heat Pump does not makes sense if a performant gas boiler is installed.

    Both above are validated by a good sealed and insulated building.

    Regards


  • Options
    #44
    murphaph
    Registered Users Posts: 19,018 ✭✭✭✭murphaph


    The actual heat source is definitely the least important decision. In a properly designed and built modern home, the heat demand should be so low that the heat source is not really that important IMO. As long as the fabric is future proofed and can allow some other heat source to be slotted in instead without ripping the whole distribution system out then it's all good.


  • Options
    #45
    matrat
    Registered Users Posts: 152 ✭✭matrat


    @tobdom, you have a PM

    rolion wrote: »
    Let's agree to disagree please.

    Solar does makes sense.Both, PV and tubes, if they are well designed and used.
    Heat Pump does not makes sense if a performant gas boiler is installed.

    Both above are validated by a good sealed and insulated building.

    Regards

    Hi Rolion,

    I would be, and i am sure prospective self builders even more so, very interested to see some numbers behind this if you could supply them. Does not match any of my findings.
    From my research PV & Solar are good supplemental sources, but given their cost, unless it is a retro fit, then when ROI is taken into account it is not a good solution. To design a new system in Ireland, it simple is not cost effective to include PV or Solar. People use them to supplement oil or gas systems, which is fine as they can reduce the use of those fuels during part of the year. But as a combined system, it is less effective than a GEO or A2W.
    I agree that at this point in time, a gas boiler is highly efficient and combined with PV or Solar, can result in a cheaper alternative to GEO or A2W. When i did the figures assuming a 20 year life span, end result is that the initial cost saving now equals a negative net result. The legal requirement to have a gas boiler serviced annually alone takes a huge dent in the saving.
    To me it is much the same as gasification boilers etc. there is an element of truth that they can be very efficient. But add in the time for labor, the fact that can anyone speak to owning one for more than 7 years, the costs to replace plates etc. then it just doenst add up. The idea that my time is free is a false economy for me and i suspect most people. If i used the same time to work then my time is not free and i would find a much larger net gain by working those hours than i would chopping wood or cleaning out boilers.

    There is a reason that GEO and A2W are used in countries throughout the world more so that these alternative sources. When designed and installed right, they simply work.


  • Options
    #46
    BarneyMc
    Registered Users Posts: 1,504 ✭✭✭BarneyMc


    At a small trade fair in Monaghan tonight and asked a rep about PV to power my A2W HP. He gave me a ball park figure of €6K.
    If this is anyway accurate then PV is not viable. We will be building on the moon before I'd see payback on that!


  • Options
    #47
    rolion
    Closed Accounts Posts: 3,362 ✭✭✭rolion


    matrat wrote: »
    @tobdom, you have a PM




    Hi Rolion,

    I would be, and i am sure prospective self builders even more so, very interested to see some numbers behind this if you could supply them. Does not match any of my findings.
    From my research PV & Solar are good supplemental sources, but given their cost, unless it is a retro fit, then when ROI is taken into account it is not a good solution. To design a new system in Ireland, it simple is not cost effective to include PV or Solar. People use them to supplement oil or gas systems, which is fine as they can reduce the use of those fuels during part of the year. But as a combined system, it is less effective than a GEO or A2W.
    I agree that at this point in time, a gas boiler is highly efficient and combined with PV or Solar, can result in a cheaper alternative to GEO or A2W. When i did the figures assuming a 20 year life span, end result is that the initial cost saving now equals a negative net result. The legal requirement to have a gas boiler serviced annually alone takes a huge dent in the saving.
    To me it is much the same as gasification boilers etc. there is an element of truth that they can be very efficient. But add in the time for labor, the fact that can anyone speak to owning one for more than 7 years, the costs to replace plates etc. then it just doenst add up. The idea that my time is free is a false economy for me and i suspect most people. If i used the same time to work then my time is not free and i would find a much larger net gain by working those hours than i would chopping wood or cleaning out boilers.

    There is a reason that GEO and A2W are used in countries throughout the world more so that these alternative sources. When designed and installed right, they simply work.


    Thanks.
    Let me rephrase it: no one in his right mind will retrofit a heatpump to an older home OR that is not at least built at standards of BER A mimum. I heard gas boiler upgrades / replacements but not a single heatpump yet.I'm not a builder.

    Re PVs vs tubes,i have both and they works fine only when God Sun decides to smile upon us ! :)

    Re "prospective builders" ... if they are the same fcuking people with no other scope than money and profit like the one(s) that built my house and for which i wanna meet and strangulate holes in his body / brain like he did with my house structure...then you are lost ! I will be pleased to meet a builder that can stand up in a conversation mhrv vs solar vs tubes vs boilers vs heapump vs airtight vs insulation !!!

    Rant over...


  • Options
    #48
    daphne
    Registered Users Posts: 65 ✭✭daphne


    In process of building - trying to future proof with regards to insulation and airtightness. Planning on Danfoss A2W. It's reassuring to see some good reviews and not crazy energy costs. Will be interesting to see how much energy exactly is required.


  • Options
    #49
    matrat
    Registered Users Posts: 152 ✭✭matrat


    daphne wrote: »
    In process of building - trying to future proof with regards to insulation and airtightness. Planning on Danfoss A2W. It's reassuring to see some good reviews and not crazy energy costs. Will be interesting to see how much energy exactly is required.
    Enjoy it daphne, 
    Yeah is definitely ways of doing it right. I was limited on structure of building and if could do that again then i would do it different and hopefully be cheaper costs again. As they say, insulation is one of the very few items that will pay for itself. Using it in the right places and the right way will make a huge difference also. See alot of people and builders using it wrongly. 
    I now have 259 days of recorded data, waiting on my latest esb bill to confirm but estimated around 614 euro so far. Given that hopefully the temp will be steady or rise from here to the 365 day mark, im hoping to be somewhere in the 800-850 range for a year of all hot water demand for two adults, two large dogs, and minimum of 21 deg temp on a 2900 sq ft house. Will be happy enough with that!! When i get some time i will calculate what the heat demand was from that and do some sums to see what it would have cost with an oil boiler, back boiler stove, immersion and electric shower!! Should be interesting!!


  • Options
    #50
    Charlie Charolais
    Registered Users Posts: 263 ✭✭Charlie Charolais


    Hi Matrat, how did you measure your electricity usage?


  • Options
    #51
    BarneyMc
    Registered Users Posts: 1,504 ✭✭✭BarneyMc


    matrat wrote: »
    As they say, insulation is one of the very few items that will pay for itself.

    Can you elaborate?


  • Advertisement
  • Options
    #52
    matrat
    Registered Users Posts: 152 ✭✭matrat


    Charlie Charolais wrote: »
    Hi Matrat, how did you measure your electricity usage?
    Hi Charlie, 
    My unit tracks the hours operating, i contacted Danfoss who advised what an hour operation is in KW/h, i track this number each week for the heat and domestic water separately and use my esb bill to determine my exact kw/h rate when i get it. Naturally it is within a tenth or two of 19c, but is more for my sanity to validate the machine isn't using alot more than it says.
    BarneyMc wrote: »
    matrat wrote: »
    As they say, insulation is one of the very few items that will pay for itself.

    Can you elaborate?
    Hi Barney, 
    Is not much to elaborate on really, if you are sensible with it then it is proven that insulation will pay for itself if used correctly. For example, pumping a cavity wall, the cost of the pumping will be offset in "X" number of years by the savings you have made in heating costs. Same rule goes for most insulation applications, the cost will be recouped. Of course you can use insulation incorrectly which will greatly increase the time it takes, or maybe never pay for itself. Alot of builders now are getting the idea that insulation is a key selling point so are using it in not very efficient ways which will naturally cause some confusion and have people say that they have a highly insulated house but dont see the savings they expect. For example, i see alot of people using insulated boards internally in a house on a full fill 4 inch cavity construction. Yes this MAY be more efficient than not having the insulated board MOST of the time, but i would consider it bad practice in this age. Especially with a low heat source like A2W and Geo, it is much more efficient to keep all the insulation in one place, which can be seen with the increase in popularity of external insulation and 6 or 8 inch cavities. This also has the added advantage of using the internal leaf as a thermal store. If i had a choice of my structure, it would be a block on its flat internally and a pumped 6 or 8 inch cavity. Gets the best of both worlds. 


  • Options
    #53
    rolion
    Closed Accounts Posts: 3,362 ✭✭✭rolion


    Also,dont forget AND ignore that with a good insulated house comes the fresh air/condensation /ventilation "hole in the budget" called MHRV ! :)


  • Options
    #54
    Water John
    Registered Users Posts: 21,171 ✭✭✭✭Water John


    Yes rolion, know a few houses that decided to 'save' on build by not installing, madness.
    One fella said, shur I open the windows when I can!!!


  • Options
    #55
    daphne
    Registered Users Posts: 65 ✭✭daphne


    Thanks Matrat. Yes, it seems there are natural limitations on what you can do with conventional masonry build. Everyone you talk to who has built house say 2013 and before seems to be sceptical re heat pumps. We pushed our house designer to 200mm cavity - anything beyond we were told we were getting into trouble re laying the inner leaf blocks - reaching across from outside scaffold not an option. Pumped cavity was default solution due to ease of installation and achieving best U-value for your buck. With 200mm cavity, the need for inner dry lining to make up U value not required it seems.
    On airtightness, we pushed in the spec for a 1ACH  - I hope this pays back but it means they're being pushed to being a bit more careful with taping up and blocking holes. Why not go the extra mile with the ACH if you're putting in the MHRV anyway. In terms of overall build cost and the cost of UFH, fancy heat pumps and triple glaze windows, it isn't a big cost. It looks like a neat and simple solution for ventilation. Hopefully it proves so!
    I think the solution on the whole self build energy thing is to do your own research, use the regs only as minimums and talk to a supplier of heat pumps who will also look at the whole house in terms of insulation, design etc. I think Passive house standard should be taken as the target/benchmark but ultimately seems to me hardly attainable with block built house. I'm not entirely convinced of the payback in an Irish climate. I admire anyone who goes down this route tho. It is the less trod path and alternative construction methods are a bit scary for most people...


  • Options
    #56
    matrat
    Registered Users Posts: 152 ✭✭matrat


    Yeah i agree with all this, i read an article back early in the process from some design manual in europe and it said that designers need to take a whole house approach and think of heating, domestic water, insulation, ventilation, glazing etc. as all pieces of the same overall element. That is more likely to be better in the long run to split a budget relatively even over all items than it is to focus on one or two. Point in case is with some 8-10 year old houses now that had HP fitted from new. I looked at one back before purchased current place, asked several times to see esb bills to validate this claim of great setup by estate agent. House never felt overly warm inside and naturally no bills where ever produced. You can be sure a large chunk of budget was spent on that HP, but vented double glazing windows didnt exactly improve upon its good basis!


  • Options
    #57
    daphne
    Registered Users Posts: 65 ✭✭daphne


    Yes, the idea of heat pump is low water temperature circulation which is not a very responsive system when you're talking about moving the temperature of a house. It requires high insulation levels to be effective in terms of comfort to occupants. Any little bit of heat that is generated by the system is retained and also heat energy is stored by the walls and material of the building.  As you were saying - dry lining is not really optimum solution. As for air tightness and MHRV, while we don't have very low temperatures, we are definitely one of the windier climates in Europe. Draughts from bathroom fans and trickle vents must account for a lot of heat loss, comparatively, in this country.
    The annoying thing is the BER classification which people take to be the "be all and end all". People just lobbing a solar panel on the roof to attain a higher BER is nuts, especially when it gives a false notion of the houses real energy performance to prospective buyers.


  • Options
    #58
    matrat
    Registered Users Posts: 152 ✭✭matrat


    Yeah it is simply down to education, but in fairness suppose it is getting on in age now and is alot better than no standard. A conversation i had a few days ago with the in-laws around upgrading their house really brought that home, a 25 year old home that raised several children, a house that contains both a boiler and non boiler stove, the ventilation system is essentially draughts. No window vents, no hole in wall vents etc. 1 generation of difference between that house and mine and is more than a few differences.
    Traditionally this country waits until UK regulations have been in place a few years and copies most of it so with the level system over there and the push to make a level mandatory for all new builds will hopefully filter to us in the near future. And i love the idea that you can make a reasoned case to build a house in a location that typically would be an issue by compromising to build it to such a high level as to have little to no impact. Is such a good compromise. You want to build a house in a scenic location owned by several generations of your family, ok, build it level 6. Great setup


  • Options
    #59
    BarneyMc
    Registered Users Posts: 1,504 ✭✭✭BarneyMc


    daphne wrote: »
    Yes, the idea of heat pump is low water temperature circulation which is not a very responsive system when you're talking about moving the temperature of a house. It requires high insulation levels to be effective in terms of comfort to occupants. Any little bit of heat that is generated by the system is retained and also heat energy is stored by the walls and material of the building. As you were saying - dry lining is not really optimum solution.

    This is exactly my setup solid, non dry-lined, wide cavity walls. I could unplug the HP and the family wouldn't notice the drop in tem for a few days. Super comfortable living!


  • Options
    #60
    KCross
    Registered Users Posts: 12,094 ✭✭✭✭KCross


    BarneyMc wrote: »
    This is exactly my setup solid, non dry-lined, wide cavity walls. I could unplug the HP and the family wouldn't notice the drop in tem for a few days. Super comfortable living!

    @BarneyMc, do you have a meter attached to your HeatPump and know exactly what it is costing you per year? Care to share? Also, what size house is it?


  • Advertisement
  • Options
    #61
    matrat
    Registered Users Posts: 152 ✭✭matrat


    Would also be very interested in your stats Barney, just to do a comparison with what is a superior structure to mine and see the actual difference


Advertisement