New Build, 7 months in with a Danfoss heatpump

Startingout

Thanks John. What type of engineer should I look for? Sorry for the stupid question but I am totally new to this.

zulutango

Most engineers won't have a clue, to be honest. I'm an engineer (more in the area of design of services for commercial buildings, but I am interested in dwellings to some extent) and my advice is to study this forum and just try and get your head around the issues. Feel free to ask questions. I'll answer if I can.

matrat

This is a very good question and highlights one of the major issues with the construction industry in Ireland.

I dont know who the best person to ask for a unique build is. I think the safest thing is to do alot of self study on methods and results and have some information and start asking people from there. First point i would assume be your architect and possibly select your architect based upon the level of input they can provide. In my opinion, if your architect cannot give you some good advise or information, or get someone involved in the project who can, eg, building services engineer, then you either take full responsibility for the energy design, or get a new architect. I knew going into my project for example that my architect was nothing more than a name on paper for the council and mortgage. And he was paid as such, not paid as if he was an architect coming to site once a week to check on things.

Also ask everyone for opinions/experience. When you have some level of knowledge from your own study, you will be amazed at the people who you expect will have some knowledge whom have none and you will get some great tips and advice from the most random of places. And a nice pinch of common sense will never go to waste. For example, if you are installing external insulation, dont employ the local contractor who may never have worked with it before. Employ the professionals to do the professional work. I have stated many times in this thread that i ended up using very few tradesmen due to a huge concern that they where alot less qualified to do the job than i was. My heating installer for example could answer all my questions and gave me some great advice and input. On the other hand, i couldnt get close to finding anyone to install and commission MHRV. Building regs are free documents to download yet not one of the guys i contacted could tell me advised flow rates from the regs!

Another update on my system,
Days in use: 357
Total Hours Heat Pump: 3548
Average Daily cost: €2.24
Average Weekly cost: €15.65
Total Heating cost: €573.24
Total DHW cost: €224.82
Total HP cost: €798.06

As listed before this is all Heat supply. House has no other heat source.
This is all DHW. House has no electric shower or immersion.
We have no solar panels, not other heat source of any kind.
I do not adjust heat or HP at anytime. This is 24/7 controlled by HP, no temperature set backs, house is constant 24c downstairs and 23c upstairs.

As always any questions please ask but overall i am delighted with the system and the cost. Never have had a minutes bother with the system in any way. Now that i have a years DATA, next step is to compare the heat output for other heat sources and compare costs!!

Water John

Thanks for the figures Marat. I think I discussed them before with you.
You are right, finding professionals, with the knowledge, in the field is difficult.

But that seems to apply to most professional areas. In business, I have found you nearly have to build up your knowledge base so, you have nearly as much as every professional you deal with. That means a good bit of homework in a number of fields. Challenging professionals will not make any of them good friends with you but they will respect and not attempt to bull***t you.

Startingout

Thanks all

Shaunoc

How has the cold winter affected your HP performance and reflected on bills? I ask as a a2w HP owner awaiting next bill cautiously

matrat

Shaunoc wrote: »

How has the cold winter affected your HP performance and reflected on bills? I ask as a a2w HP owner awaiting next bill cautiously

Hi Shaunoc,

Fortunately we missed the majority of the snow so have only had to deal with some cold days. We have had no issues with hp though. The borehole geo is pretty much unaffected by the majority of weather conditions so have not seen any unexpected increases in cost. The most expensive week was still under 37€ for all the heat and all the hot water. Be coming up on 2 years in May and weekly average is around 16€ which I am delighted with.

Shaun

Shaunoc

Thanks Shaun

We had plenty of snow and colder nights in the last 2 months. Much cooler compared to last winter, so i had a small worry.
I finally went through utility billing this morning - since we moved in (Sept 2016) and included current actual bill reading (March 12th):
My monthly average looks to be 108 euro per month for all electricity usage.
That is based on 18 months billing through 2 winters from Sept 2016.
Danfoss DHP-AQ 13kW - 346 sqm house
MJ mix of DG and TG (kitchekn and living room) windows

We do use a small wood stove a few evenings of the week from Nov onwards.
There is always someone in house with a lights/laptops/tv/kettle/washer/dryer on the go. I should invest in a one cup kettle!
If I could go back, I would have rearranged the budget for Geo borehole, but overall I can have no complaints with bills and ease of use of A2W.

Shaun

Water John

Those are great figures. It's interesting to see, is the borehole W2W worth the extra cost? Probably not in terms of ROI but maybe their is a bit more, peace of mind. Personal choice it seems.

FiOT

Shaunoc wrote: »

How has the cold winter affected your HP performance and reflected on bills? I ask as a a2w HP owner awaiting next bill cautiously

Our Bill from the end of November to the end of January was 180e for heat, hot water and electricity but they were fairly mild months. Also waiting and wondering what our bill will be this month after the snow, it seemed like our outdoor unit never stopped for the whole time the snow was on the ground. We have an A2 rated house with air tightness result of 0.9 so it holds the heat very well - we'll know in a few days what the damage is!

gooner99

matrat wrote: »

Hi Shaunoc,

Fortunately we missed the majority of the snow so have only had to deal with some cold days. We have had no issues with hp though. The borehole geo is pretty much unaffected by the majority of weather conditions so have not seen any unexpected increases in cost. The most expensive week was still under 37€ for all the heat and all the hot water. Be coming up on 2 years in May and weekly average is around 16€ which I am delighted with.

Shaun

Hi Shaun. Can you give details of your Geo setup ?

matrat

Shaunoc wrote: »

Thanks Shaun

We had plenty of snow and colder nights in the last 2 months. Much cooler compared to last winter, so i had a small worry.
I finally went through utility billing this morning - since we moved in (Sept 2016) and included current actual bill reading (March 12th):
My monthly average looks to be 108 euro per month for all electricity usage.
That is based on 18 months billing through 2 winters from Sept 2016.
Danfoss DHP-AQ 13kW - 346 sqm house
MJ mix of DG and TG (kitchekn and living room) windows

We do use a small wood stove a few evenings of the week from Nov onwards.
There is always someone in house with a lights/laptops/tv/kettle/washer/dryer on the go. I should invest in a one cup kettle!
If I could go back, I would have rearranged the budget for Geo borehole, but overall I can have no complaints with bills and ease of use of A2W.

Shaun

Hi Shaun,

Cant complain with those sort of bills for a house that size, seems a great setup you have!

How do you find using the stove with the heating system? We left an air intake and chimney for a wood burning stove but we have thought since that due to the heat already in the house it may be a bit uncomfortable. Still have done nothing with the space though so still could be on the cards. I have a temp recorder on kitchen fridge and lowest it has ever gotten to is 22.1c and highest is 26.0c. Wife is a heat maniac so is an expense for a quiet life. I think if we kept the living areas at a more normal temp then would def be a nice feature.

I would have to agree with Water John that at those sort of costs, it is hard to see any ROI on the geo with borehole over your a2w. The only unknown factor is performance or reliability issues over comparable lifespan but we both are going into the unknown there. Fingers crossed for both of us that we get plenty of years at these costs!!

matrat

gooner99 wrote: »

Hi Shaun. Can you give details of your Geo setup ?

Hi Gooner99,

What sort of details are you looking for?
My machine is a Danfoss DHP-H Opti 8 SP, standard borehole, think about 120m, underfloor all over, stats in bedrooms only, machine has heat curve set and is never touched, no set backs etc. Very happy with the setup overall, is massive change over traditional poorly insulated irish house with radiators, solid fuel stove etc. Would def struggle to ever go back to that!

Shaunoc

matrat wrote: »

Hi Shaun,

Cant complain with those sort of bills for a house that size, seems a great setup you have!

How do you find using the stove with the heating system? We left an air intake and chimney for a wood burning stove but we have thought since that due to the heat already in the house it may be a bit uncomfortable. Still have done nothing with the space though so still could be on the cards. I have a temp recorder on kitchen fridge and lowest it has ever gotten to is 22.1c and highest is 26.0c. Wife is a heat maniac so is an expense for a quiet life. I think if we kept the living areas at a more normal temp then would def be a nice feature.

I would have to agree with Water John that at those sort of costs, it is hard to see any ROI on the geo with borehole over your a2w. The only unknown factor is performance or reliability issues over comparable lifespan but we both are going into the unknown there. Fingers crossed for both of us that we get plenty of years at these costs!!

Have a 5kw wood stove - small enough but its got a big heart! (excuse the pun).
I wouldn't be without it now, easy to look after - have an old wet/dry vaccum from the build that use to keep the stove clean - hassle free.
It is in a large open plan kitchen living room so it never gets too over bearing and doesn't need alot of wood to keep it going for the evening. Creates a nice atmosphere and focal point.
We keep living space at 21 degrees and bedrooms at 18, so compared to your tropic conditions the stove is no harm.
It also gives me the excuse to cut/chop/stack look at wood, a good spring pasttime/exercise, which just started today!

The Geo longevity and steadiness (harsh prolonged winter) over the A2W is what I admire but not enough at purchase time not to have too many regrets just now. Fingers crossed indeed

Water John

Just realised that I have a disused borehole just outside the house. That should help make my decision should I go towards a HP.

Stiof

If I could go back, I would have rearranged the budget for Geo borehole, but overall I can have no complaints with bills and ease of use of A2W.

Shaun[/QUOTE]

Hi Shaun, just at the stage of choosing between A2W and Geo borehole now, could you PM me on reason you'd go for Geo borehole over A2W?
Thanks

Shaunoc

Hi Stiof

I believe you will find many references/conversations in threads on boards about benefits of each over one another.
To follow - incredibly simplified summary from my thoughts - it is a while since i picked and I am a layman, not a salesman

I liked the simple plug and play of A2W. It was installed and commissioned within a day.
A2W is less efficient under certain degrees than Geo and better at higher ones. That was my concern due to recent prolonged cold snap. I wouldn't like a month or 2 of that every winter as the compressor may have a poo sooner than it should. Geo is not affected like that and is supposed to be a very steady operator in adverse weather = doesn't have to work harder = less maintenance = last longer.

There is a bigger capital cost in Geo - but not significantly more, I understand due to groundworks costs. Depends on the bore hold depth or if 2 needed. Perhaps there is ground type relevance. Better to ask an expert.
I don't like the idea of horizontal grid of pipework that would limit planting options in lawn for Geo if not going borehole approach.
I liked knowing what the A2W cost would be from the outset instead of potential borehole needing to be 200 metres or 300 metres or 2 required. I didn't price that. Perhaps others here may have more info for you.
Perhaps naivety on my part, but if something went wrong with Geo, I assumed it may be harder to fix - I may be 100% wrong there.

In short if I had a bigger kitty/or rearranged my existing kitty I would like to have Geo with borehole as I like the idea of getting heat from the ground. Too late now so no regrets hopefully for next 15 years (i hope)

tdiman

Can I ask a question here. Our house was built in 2006, standard oil central heating, no UF, all rads. How easy is it to fit these types of systems to the house now? Insulation levels are likely lower than today's specs and the house is around 3000 sqft. But its always cold. Thxs.

Shaunoc

tdiman wrote: »

Can I ask a question here. Our house was built in 2006, standard oil central heating, no UF, all rads. How easy is it to fit these types of systems to the house now? Insulation levels are likely lower than today's specs and the house is around 3000 sqft. But its always cold. Thxs.

From my understanding, you want to have a certain level of airtightness and insulation before considering a heat pump, otherwise it would have to work too hard, costing you money and the making heatpump life expectancy shorter
Probably other means for you to target your heat loss and air tightness before changing heat source. Might be best to get a professional to do a heat loss survey

KCross

tdiman wrote: »

Can I ask a question here. Our house was built in 2006, standard oil central heating, no UF, all rads. How easy is it to fit these types of systems to the house now? Insulation levels are likely lower than today's specs and the house is around 3000 sqft. But its always cold. Thxs.

Thats your answer right there.

If its cold now with oil it will be cold with a heat pump. The heat pump isnt magic fairy dust!

You can retrofit a heat pump but you'd need to fix the insulation, windows/doors and airtightness first. You might find that once you've done that that the oil will do as is.

Its generally not a good idea to use a heat pump with standard steel rads unless they were oversized to begin with. You'd need an assessment carried out to determine if they were suitable or not. If they are not you'd have to replace them with aluminium rads in lieu of putting in UFH.

matrat

Update as of 25 May 2019:

House located in Letterkenny, relatively sheltered site.
Total Number of Days Recorded: 1092 (156 weeks / 3 years)
Total Hours Heat Pump: 8715
Average Daily cost: €2.24 (Based on average 0.1928c per unit paid)
Average Weekly cost: €15.66
Total Heating cost: €1718.09
Total DHW cost: €724.68
Total HP cost: €2442.77

Heating Cost & DHW Costs calculated based upon figures provided by Danfoss for HP, each hour on Heat mode is 2kw, each hour on DHW mode is 2.7kw.

Lowest recorded temperature in kitchen is 19.9c.
Lowest recorded temperature in Master Bed is 19.1c.
No other sources of heat.
No maintenance costs, although may look into a HP Service this summer.

Overall still delighted we made the choice to go for Geo HP, completely faultless so far!

Please feel free with any questions etc.

KCross

matrat wrote: »

Average Daily cost: €2.24 (Based on average 0.1928c per unit paid)

You're not really paying 19c though, are you?

Surely you have night rate electricity and only paying a fraction of what youve shown above?

matrat

KCross wrote: »

You're not really paying 19c though, are you?

Surely you have night rate electricity and only paying a fraction of what youve shown above?

Yeah, take the total cost of bill, including VAT, divide by number of units and that's what I'm paying. Could switch to night rate but would mean taking more control of when appliances and hp are used etc which i may do in conjunction with using solar on our next build but not something we spent anytime working on at the min.

KCross

matrat wrote: »

Yeah, take the total cost of bill, including VAT, divide by number of units and that's what I'm paying. Could switch to night rate but would mean taking more control of when appliances and hp are used etc which i may do in conjunction with using solar on our next build but not something we spent anytime working on at the min.

I think you are screwing yourself big time.

You should be on a night rate bill. You will see significant reductions in your bills if you do.

Your heat pump runs at night and you can also tell it to only heat water at night. All of that will be done at half the price you are paying right now and doesnt require any micro managing on your part.

It will still run during the day too but if all your night usage is half the price you will see a reduction in your bills.


NOTE: When you switch to day/night rate your day rate will go up 1c/unit but your night rate will be half price and the standing charge is about an extra €45.... even with the extra standing charge and 1c increase on day rate you will still save significantly.

I currently pay 17.44/8.63 inc vat for day/night respectively. You are paying way over the odds.

Water John

Ha had misread that, didn't see the 3 years. so it's about €800/year. As Kcross says you should be able to knock a good bit off that, with night rate management.
BTW don't think I could sleep if the bedroom was at 19 C, staying very cosy.

matrat

Can't argue with your logic, will give bord gáis a call tomorrow and give it a go!! Thanks for the advice!

KCross

matrat wrote: »

Can't argue with your logic, will give bord gáis a call tomorrow and give it a go!! Thanks for the advice!

Price around. Energia and airtricity might be cheaper again.

Shaunoc

matrat wrote: »

Can't argue with your logic, will give bord gáis a call tomorrow and give it a go!! Thanks for the advice!

use the comparison sites and set a reminder annually and keep changing provider as they all do you after 12 months by upping the price per unit. never once have elec provider offered to match or beat unit price of the competitor so i switch every year. Treat them same as you would any other bill - only takes a few minutes. O yeah a night rate for the A2W !

Ging Ging

Hi guys, I built a 2,400sq ft house, single block on flat with external insulation (200mm), ground source danfoss heat pump (not borehole), heating and electricity on 12 months but only living in house 9 months, cost to date for all electricity (includes heating and hot water) is €1,115. Normal bill seemed to be €240ish every 2 months, last 2 months was €140, the heating barely kicked in all during this period so its hot water production plus other electricity usage, its on weather compensator so I didn't actually have to turn it on/off. The difference between latest bill and my winter bills is about 100 euro so I take it from this that last winter the heating cost about 50 euro per month to run, house always 19/20/21 degrees depending on stats, a few warm days might see solar gain push it to 22.


Heat pump is Danfoss DHP-H Opti 8 SP ground collector loop is 400m I think. MY question is there a better way to control hot water production, currently it gives it prioity and if it falls below a set point ( I think around 42 degrees) it will kick in and heat the tank up to 58. However I don't use a lot of hot water at the moment as it is only me living here, and as I am on night rate I would like to restrict it from automatically running during the day time higher cost hours. I cant see any options in the Danfoss controller to time hot water or anything like that.

matrat

My danfoss machine has a separate power supply for hot water over heating so you could always put a timer switch on the power feed but prob not advised. Might be a bit late now but I think more standard approaches are to use buffer tanks or solar tubes to achieve higher efficiency.

Ging Ging wrote: »

Hi guys, I built a 2,400sq ft house, single block on flat with external insulation (200mm), ground source danfoss heat pump (not borehole), heating and electricity on 12 months but only living in house 9 months, cost to date for all electricity (includes heating and hot water) is €1,115. Normal bill seemed to be €240ish every 2 months, last 2 months was €140, the heating barely kicked in all during this period so its hot water production plus other electricity usage, its on weather compensator so I didn't actually have to turn it on/off. The difference between latest bill and my winter bills is about 100 euro so I take it from this that last winter the heating cost about 50 euro per month to run, house always 19/20/21 degrees depending on stats, a few warm days might see solar gain push it to 22.


Heat pump is Danfoss DHP-H Opti 8 SP ground collector loop is 400m I think. MY question is there a better way to control hot water production, currently it gives it prioity and if it falls below a set point ( I think around 42 degrees) it will kick in and heat the tank up to 58. However I don't use a lot of hot water at the moment as it is only me living here, and as I am on night rate I would like to restrict it from automatically running during the day time higher cost hours. I cant see any options in the Danfoss controller to time hot water or anything like that.