Assistance in English please

[Andrew]

Hi

I am ready to install a ground heat system to replace my oil boiler if i can be convinced that it will be economical compared to district heating

Is there anybody here who is able to comment on that sort of thing?

Also i am interested in a DIY project and DIY maintenance rather than getting locked into contracts with monopoly suppliers - hence the attraction of a heat pump i can buy myself and replace myself.

However if i can be persuaded the system is going to work and be economical i would go with an entirely professionally installed system today rather than play around with it myself.    I have had some quotes for that and tax credits might make it work.

The problem for us is that we are in an information black hole as far as knowing people who have these things operating thru the winter.   We also got a scare story from a couple who have a swimming pool and the costs did not look good at all.    We dont have a pool but we are using about 5000 liters of oil per year.

In Southern Finland could you install a 'surface' ground loop and how deep would it have to be?

I can translate your technical Finnish or my Finnish wife can but it is a bit difficult to get her to write down the Finnish and deal with my questions she does not understand  :-/

Any help here much appreciated thanks.

[tomppeli]

If you house annually consume abt. 5000 ltrs oil for heating, it means abt 44.000kWh of consumed heating power.
To produce it, is needed  about 16-17kW heatpump.
Ask pump and installation prices from plumbing companies.
If in your house it is used heat radiators, the system needs a thermal accumulator for circulation water, that means a hot water tank of at least 300 ltr in radiator circulation system.

You need a Thermal wells of about 200m active deep for your house.
Active deepness means that part of wells, where always is water.
To bore wells costs abt. 30€ / 1m, including collector tubes and filling with alcohol.
Connection between wells and heat pump is not included in that price.

Warning. Be carefull.
We are not able to guarantee calculations. Please, trust specialists to make your  house heating plan.
...

I hope, that you can understand my poor English!!

[Andrew]

We have been told by the salesmen that 12kw is sufficient.    Nobody seems to have done a specialist calculation but instead they have relied on our 5000 l of oil consumption.    Which is reasonable as every house is unique.

So we were told that  a 16kw system is not economic for the small amount of time it is required when the built in 3/6/9KW of electric heat can be turned on for the small amount of time when 16kw is required.

One question we have though is how does district heating compare to ground heat in long term costs because all salesmen have only compared our expensive oil consumption to the favourable comparison of ground heat.

The problem with ground heat is that we are reliant on salesmen and dont yet have a source of independant information.

[hoohöö]

Hello,

I assume there is some salesmans&professionals reading this forum and also giving comments, I'm not professional of salesman but I'm sure you will be able to reduce heating costs by going to ground heat but how much, that's the question, and thus how long time it will take to pay back the investments.
5000l means approx. 50000kwh of energy per year so I guess you have approx. 400-500m2 of "bungalow" or in case the house is older and not that well insulated maybe smaller (350m2), and maybe you also consume plenty of hot water as well.
I have about 220m2 house and I decided to buy 10kw pump, so based on this I would say you need approx. 15kw to 20kw pump (in case you would like to survive without additional electrically created heat during winter).
And in case of 17kw pump you would need approx. 2x400m or 3x300m ground loop (or drilled hole active depht approx. 2x140m).
So you need pretty large back yard if you go to ground surface loops.
Price of nibe 1145-17kw is about 6700€ but you will need also "heat capacitor", i.e big water tank etc, so it is best to buy the whole system from known good dealer.
In case you have old&not so efficient heat radiators in the building you might get less energy savings by the heat pump compared to low temp. floor heating (smaller COP) but I believe you should in any case save at least 50% of energy, i.e. worth of 2500l oil per year

[Andrew]

Hello,

I assume there is some salesmans&professionals reading this forum and also giving comments, I'm not professional of salesman but I'm sure you will be able to reduce heating costs by going to ground heat but how much, that's the question, and thus how long time it will take to pay back the investments.
5000l means approx. 50000kwh of energy per year so I guess you have approx. 400-500m2 of "bungalow" or in case the house is older and not that well insulated maybe smaller (350m2), and maybe you also consume plenty of hot water as well.
I have about 220m2 house and I decided to buy 10kw pump, so based on this I would say you need approx. 15kw to 20kw pump (in case you would like to survive without additional electrically created heat during winter).
And in case of 17kw pump you would need approx. 2x400m or 3x300m ground loop (or drilled hole active depht approx. 2x140m).
So you need pretty large back yard if you go to ground surface loops.
Price of nibe 1145-17kw is about 6700€ but you will need also "heat capacitor", i.e big water tank etc, so it is best to buy the whole system from known good dealer.
In case you have old&not so efficient heat radiators in the building you might get less energy savings by the heat pump compared to low temp. floor heating (smaller COP) but I believe you should in any case save at least 50% of energy, i.e. worth of 2500l oil per year

Our house is only 220 including basement areas. 160m2 living areas.    Boiler is old.  Our radiators need about 59 degrees at -24  We dont have room for hundreds of metres of surface pipes depending on how close those pipes can be . beside that would be a hell of a digging job even with a machine - thanks for the information.   30€ per meter of well sounds very reasonable.

District heating versus ground heat?     If we knew how many kilowatts we actually needed it would help.    

Based on what you are saying it might be worthwhile to electrically heat the house for a week to see how much we use now and then calculate somehow the likely total heat requirements.

Do you know how to do such a calculation?

[hoohöö]

well 220m2 versus 5000l,  indeed there is some mismatch what comes to energy consumption and area, or maybe no too much insulation in the house or plenty of warm water consumed.
As stated I'm not professional so can not say what is the maximum power needed during the coldest days of the year for keeping your house warm (depends of space of the house, air leaks, heat dissipation of walls&sealing etc) but I'm sure 17kw pump would do that for most of the time. 8kw -12kw should be enough for 220m2 if the house is build 2000 or later.
Price difference of pumps between 12-17kw is minor but depth of drilled hole is much higher if you go to 17kw, maybe something like 1x220m versus 2x160m, but in euros thats only about 4200€ so would choose 2x160 and 17kw

[Andrew]

well 220m2 versus 5000l,  indeed there is some mismatch what comes to energy consumption and area, or maybe no too much insulation in the house or plenty of warm water consumed.
As stated I'm not professional so can not say what is the maximum power needed during the coldest days of the year for keeping your house warm (depends of space of the house, air leaks, heat dissipation of walls&sealing etc) but I'm sure 17kw pump would do that for most of the time. 8kw -12kw should be enough for 220m2 if the house is build 2000 or later.
Price difference of pumps between 12-17kw is minor but depth of drilled hole is much higher if you go to 17kw, maybe something like 1x220m versus 2x160m, but in euros thats only about 4200€ so would choose 2x160 and 17kw

are you saying i can get 2x160 with the utube and filled for 4200?    I thought this would be more like 9600? at 30 per meter?

We had quotes for 26000 for 17 and 22000 for 12
 

[hoohöö]

sorry, was not clearly communicated; I ment price difference between the heat sources/holes for 12kw versus 17kw.
Drilling with the tubes, brine etc is usually 30€/m (I paid 27€/m).
Maybe you should choose "compromise", i.e 15kw pump. 17kw most likely is bit too powerful and 12kw might be not enough during the coldest days of winter (even it should be for 220m2 house but your oil consumption is so high that I doubt 12kw is enough).
Nibe's installer manual is saying 15kw pump usually requires 2x120m deep holes (active depth) but in case of 12kw pump you might survive by one 220m hole (I have 219m for 10kw pump, approx. 200 meter in "stone" so active depth might be about 200m).
I paid about 15k€ for 1145-10 and VPB300 with installation, but it included installations inside the house only, so I did some "heavy and simple" work by myself. Installation of the heat pump itself cost 2350€ with materials (pipes, valves etc, 21 hours of work x50€ + material 1300 ) but I have very simple setup, no additional water tanks or pumps etc.

[sailor]

@ Andrew

You get 60% off from drilling and install work. It's called "kotitalousvähennys" for Finnish and you get it only from work.

Show your wife: http://www.tax.fi/?language=ENG&domain=VERO_ENGLISH&path=5,40&article=8348&index=&#yksitoista

As I couldn't find it for English. (http://www.tax.fi/?path=488,493&domain=VERO_ENGLISH&language=ENG)

Jani

EDIT: "We had quotes for 26000 for 17 and 22000 for 12"

That we call "reilu meininki" --> at least 5000€ pure air

Let your wife read to you: http://www.maalampofoorumi.fi/index.php?topic=3315.0

[Andrew]

@hoohöö

Thanks for your help here.  I appreciate the hand holding you are doing here and it is helping me to put it all together.

Unfortunately as Sailor is saying there is little incentive to do DIY work in Finland if you can get the tax credits?    for a 12kw system it would be 6000/1000 plus parts for the boiler, 6000 for the well.   With upto 6000 of tax credits that reduces the professionals 20,000 installation to 14000?   Oops. well would be 60% of 6000 after tax credit

I dont have a problem paying that kind of money if the thing is going to work without huge electricity bills because of the resistance coming on more than expected.   Heat pumps are however a huge unknown for me.

@Sailor

The way it seems to work on tax credits is that because of the tax credits the price is raised by a few thousand euros which we pay to the installer and we then pay less tax to the government.

-------------

The installers are saying it is not worth getting a more powerful heat pump because it is only required for a few months a year and the difference can be made up by the 3kw/6kw/9kw resistance, where 6kw should be sufficient and 9kw is for back up.

You guys are all saying i need something more powerful.   Are you taking these economic things into consideration?

Is 12kw going to be undersize for us?

Our boiler was installed in 1968!  when the house was built.   it has insulated cavity walls and double glazing rather than triple glazing.

Even so we are using up that 5000l of oil per year.

[hoohöö]

If I was you I would "nail down" decision regarding size of pump and depth of "heat hole"; from investmen and payback time point of view 12kw might be the most wise as you would spend much less money for drilling compared to for example 15kw pump.
After decision done just go and request quotations from all heat pump vendors there doing business; please note also some hardware stores do provide heat pumps (K-rauta etc) and also arrange installation.
DIY part could be that you buy drilling and heat pump with installation "independently", in case you happen to get drilling cheaper by that way (as I did).
Some cost breakdown here;
- 12kw pump 5700€ (taloon.com)
- 220m drilling with pipes etc 6600€ (which from you will get approx. 3100€ tax refund)
- If you would need water heater like VPB-300 it would cost approx. 1600€
- buffer vessel of 300l approx. 800€
- Other materials, pipes, valves etc 2000€
- Installation work for example 48 hours x 50€ = 2400€ (which from you will get 60% as tax refund, 48 hours is just rough estimation and actually installation should take max. 32 hours I would say)
- Total 19100€
- "Extra" Profit taken by vendor 10% = 1900€ -> 21000€

[Andrew]

If I was you I would "nail down" decision regarding size of pump and depth of "heat hole"; from investmen and payback time point of view 12kw might be the most wise as you would spend much less money for drilling compared to for example 15kw pump.
After decision done just go and request quotations from all heat pump vendors there doing business; please note also some hardware stores do provide heat pumps (K-rauta etc) and also arrange installation.
DIY part could be that you buy drilling and heat pump with installation "independently", in case you happen to get drilling cheaper by that way (as I did).
Some cost breakdown here;
- 12kw pump 5700€ (taloon.com)
- 220m drilling with pipes etc 6600€ (which from you will get approx. 3100€ tax refund)
- If you would need water heater like VPB-300 it would cost approx. 1600€
- buffer vessel of 300l approx. 800€
- Other materials, pipes, valves etc 2000€
- Installation work for example 48 hours x 50€ = 2400€ (which from you will get 60% as tax refund, 48 hours is just rough estimation and actually installation should take max. 32 hours I would say)
- Total 19100€
- "Extra" Profit taken by vendor 10% = 1900€ -> 21000€

Thanks.  Another poster mentioned the 300l tank.   We have been told we do not need a 300l tank if we do not have thermostaticly controlled radiators.    Can you confirm that is true please.

If we need the 300l tank then the 12kw quote we have would be 21000!    just as you say.  Quote though was for a 190m well.

[Andrew]

If I was you I would "nail down" decision regarding size of pump and depth of "heat hole"; from investmen and payback time point of view 12kw might be the most wise as you would spend much less money for drilling compared to for example 15kw pump.
After decision done just go and request quotations from all heat pump vendors there doing business; please note also some hardware stores do provide heat pumps (K-rauta etc) and also arrange installation.
DIY part could be that you buy drilling and heat pump with installation "independently", in case you happen to get drilling cheaper by that way (as I did).
Some cost breakdown here;
- 12kw pump 5700€ (taloon.com)
- 220m drilling with pipes etc 6600€ (which from you will get approx. 3100€ tax refund)
- If you would need water heater like VPB-300 it would cost approx. 1600€
- buffer vessel of 300l approx. 800€
- Other materials, pipes, valves etc 2000€
- Installation work for example 48 hours x 50€ = 2400€ (which from you will get 60% as tax refund, 48 hours is just rough estimation and actually installation should take max. 32 hours I would say)
- Total 19100€
- "Extra" Profit taken by vendor 10% = 1900€ -> 21000€

Our 20,000 quote did not include a 300l tank because we do not have thermostaticly controlled radiators.  That would make the quote 21000 with a 190m hole , but with different manufacture to your suggestion.  I am a bit reluctant to say who at the moment.

Can you confirm the 300 l tank is optional?

Since you have a running system can you tell me how much power it consumes for various temperatures outside.  I was surprised we could not get this information from the supplier.

For example do you know anybody else doing the following?

http://www.elisanet.fi/sanyoco2log/

[hoohöö]

Hola,

I'm sure you need some buffer vessel there; if you don't have any old  water tank in the system you could use then you need to buy new one. I'm not aware of what would be optimal size of the vessel but bigger the better (buffer vessel does minimize temp. cycling of radiators/heating water and by that minimize possible sound comings from radiators/pipes caused by the temp. variation during heating cycles). 300l is kind of "middle size" (there is range of 100l to 500l).
I'm not expert but I wonder if the old boiler is somehow "wasting" the oil and energy and that's the reason your oil consumption is such a high; maybe the max. power needed for heating your house is not directly correlated to the oil consumption in this case.
I have seen somewhere estimation that max. heating power of 60W/m2 is usually enough for houses in Finland; that would mean peak power of 13,2kw in 220m2 building. In new buildings this estimation is not valid but maybe it's valid in your case. Anyhow 12kw pump would still be OK in this case I would say.  

[Andrew]

Hola,

I'm sure you need some buffer vessel there; if you don't have any old  water tank in the system you could use then you need to buy new one. I'm not aware of what would be optimal size of the vessel but bigger the better (buffer vessel does minimize temp. cycling of radiators/heating water and by that minimize possible sound comings from radiators/pipes caused by the temp. variation during heating cycles). 300l is kind of "middle size" (there is range of 100l to 500l).
I'm not expert but I wonder if the old boiler is somehow "wasting" the oil and energy and that's the reason your oil consumption is such a high; maybe the max. power needed for heating your house is not directly correlated to the oil consumption in this case.
I have seen somewhere estimation that max. heating power of 60W/m2 is usually enough for houses in Finland; that would mean peak power of 13,2kw in 220m2 building. In new buildings this estimation is not valid but maybe it's valid in your case. Anyhow 12kw pump would still be OK in this case I would say.  

 

There is useable heat going up the chimney.  Fairly warm air coming out of that - it is not a condensing boiler so steam appears outside.

Creaking radiators would be annoying for me at night in particular so it sounds like i need a buffer tank.   My current system keeps the radiator temperatures that 'click' to within a total 1.5 degree variation and they still click even so.  I can only control temperature outside of 33.0 and 34.0 for example rather than decimal amounts either side of 33.5, so once the boiler comes on it can go from 33.1 to 34.5 fairly quickly.

Do you have any data on actual temperatures for your system and did you have it running last year when it was so incredibly cold for months on end?  Even in helsinki we had below -18 continuously for at least 3 months as i recall.

Do you know anybody doing this kind of thing?

http://www.elisanet.fi/sanyoco2log/

When it is -25 how much power do you consume via the heat pump and resistances?

Thanks for your patience here!

[hoohöö]

Unfortunately I have had my system up and running only since September 2010 so can not say if the 10kw will be enough during winter. Anyhow most of pump vendors proposed 8kw pump (only one vendor out of maybe 5 suggested 10kw) but after reviewing the energy calculations of different offers I deviced to take 10kw (even I originally had considered 12kw pump).
Energy calculations done by pump vendors shows that 10kw pump would be enough without heat produced by resistances at least up to -32 cels temp, to be seen if this is valid.
I had electric boiler in past and it displayed actual power in steps of ~2kw while max. power of the boiler was 13kw; during some of the cold days (-30cels) I checked the power display and it indicated that something like ~11kw max. power was in use.

Here's a link to log file showing my pump's behaviour during a period when outside temp. was +6 cels.:
http://www.aijaa.com/v.php?i=6904309.png

As you can see there is quite a variation in the BT2&BT3 (heating water going&returning to/from floor) during&between the heating cycles so in case you have radiators the variation would be even higher without buffer tank (I do not have any buffer tank, it's not mandatory in floor heating as the concrete floor acts as a buffer).
BT1 is outside temp. and "lask.meno" is calculated supply (target temp for heating).
There is two high temp. peaks of approx. +58 cels in the log; that's when pump was heating "tap" water.

10kw pump takes energy max. ~2,4kw without resistances.
I guess my 10kw pump will stay on about 24hours during the extreme cold days...so would consume about 60kwh during a day while my electric boiler most likely consumed about 250kwh during cold day..

[Andrew]

Unfortunately I have had my system up and running only since September 2010 so can not say if the 10kw will be enough during winter. Anyhow most of pump vendors proposed 8kw pump (only one vendor out of maybe 5 suggested 10kw) but after reviewing the energy calculations of different offers I deviced to take 10kw (even I originally had considered 12kw pump).
Energy calculations done by pump vendors shows that 10kw pump would be enough without heat produced by resistances at least up to -32 cels temp, to be seen if this is valid.
I had electric boiler in past and it displayed actual power in steps of ~2kw while max. power of the boiler was 13kw; during some of the cold days (-30cels) I checked the power display and it indicated that something like ~11kw max. power was in use.

Here's a link to log file showing my pump's behaviour during a period when outside temp. was +6 cels.:
http://www.aijaa.com/v.php?i=6904309.png

As you can see there is quite a variation in the BT2&BT3 (heating water going&returning to/from floor) during&between the heating cycles so in case you have radiators the variation would be even higher without buffer tank (I do not have any buffer tank, it's not mandatory in floor heating as the concrete floor acts as a buffer).
BT1 is outside temp. and "lask.meno" is calculated supply (target temp for heating).
There is two high temp. peaks of approx. +58 cels in the log; that's when pump was heating "tap" water.

10kw pump takes energy max. ~2,4kw without resistances.
I guess my 10kw pump will stay on about 24hours during the extreme cold days...so would consume about 60kwh during a day while my electric boiler most likely consumed about 250kwh during cold day..

Thats great that you had the electric boiler.  You are more or less guaranteed to get the expected savings.

It sounds very impressive.

So now i know two people with a heat pump who had it installed this summer!  and none who went thru the winter!

[hoohöö]

Hello,

I'm sure you will save plenty of energy by going to ground heat; even if your house would require for example 15kw max.power during -20cels winter day you would need only 3kw of additional energy (in case of 12kw pump) for relatively short period of time so in yearly level savings will be remarkable in any case.
I did make preliminary check of energy consumption during October and looks like I will save about 50% of electricity compared to 2009 October, will know for sure at 31st of Oct.

Are you going to buy a pump with integrated water heater/tank (tap water) or by separate heater tank?
I did choose separate (1145-10 pump and VPB-300 water heater) but 1245-10 would have been quite much cheaper, also because installation would have been bit simpler.
Please note the cost breakdown I did is done using max. material and installation prices I could imagine, so you should not pay over 20k for the 12kw setup...at least if you choose swedish pump like nibe or thermia (danfoss).

[Andrew]

Hello,

I'm sure you will save plenty of energy by going to ground heat; even if your house would require for example 15kw max.power during -20cels winter day you would need only 3kw of additional energy (in case of 12kw pump) for relatively short period of time so in yearly level savings will be remarkable in any case.
I did make preliminary check of energy consumption during October and looks like I will save about 50% of electricity compared to 2009 October, will know for sure at 31st of Oct.

Are you going to buy a pump with integrated water heater/tank (tap water) or by separate heater tank?
I did choose separate (1145-10 pump and VPB-300 water heater) but 1245-10 would have been quite much cheaper, also because installation would have been bit simpler.
Please note the cost breakdown I did is done using max. material and installation prices I could imagine, so you should not pay over 20k for the 12kw setup...at least if you choose swedish pump like nibe or thermia (danfoss).

As I mentioned a few times we can get district heating so that is what we have to beat.

We were told the pump would be using resistance heating once  -10 was reached.

I asked for graphs of consumption at different temperatures and they said there were none.

I just want this thing to work        And i am wondering about that.

In the end we settled on built in 180l of hot water for a simpler installation and said we would deal with the old boiler and so forth in the hope we would save money.

Already i am seeing we are going to be going thru another winter without having made a decision if we are not careful.    :-/

[hoohöö]

Ouh, did not catch what district heating means before now; it's kaukolämpö in finnish...
Well district heating is good, can not argue about that and I would have chosen it 5 years ago when the house was build if district heating would have been available on street my house locates.
If total investment cost of the district heating is about the same or less as let's say 15kw ground heat system district will most likely beat ground heat, even I'm not aware of how much the monthly fees&costs are for district...

[Andrew]

Ouh, did not catch what district heating means before now; it's kaukolämpö in finnish...
Well district heating is good, can not argue about that and I would have chosen it 5 years ago when the house was build if district heating would have been available on street my house locates.
If total investment cost of the district heating is about the same or less as let's say 15kw ground heat system district will most likely beat ground heat, even I'm not aware of how much the monthly fees&costs are for district...

helsinki district heating will cost about 14000 to install.

700 fixed useage fee per year
total cost for our house about 1900 per year.

Sorry i have some more questions!

How long would you expect a scroll compressor to last so that it was still reasonably quiet?

Do the pump motors begin to get more noisy fairly quickly?    

Our quote says cost of maintenance is 100 per year.   Is that realistic?  I note the same company is quoting 180 just for an optimising annual check.     What are you expecting your costs to be?

[sailor]

Helsingin kaukolämpö on suurissa ongelmissa tuottaessaan kaukolämpöä maakaasulla ja kivihiilellä. Molempien verot nousevat voimakkaasti, ja kuluttaja maksaa. Maalämpö on ainakin lattialämmitystaloissa aina edullisempi käytössä kuin kaukolämpö.

[hoohöö]

How long would you expect a scroll compressor to last so that it was still reasonably quiet?
my nibe 1145-10 does have old type of piston compressor, but I expect it to last ten years at least, scroll might be more reliable (nibe 12kw-17kw seems to have scroll while 10kw and smaller have piston). But must say 1145-10 is very quiet, almost like fridge, and I don't expect noise level to increase during time (as it does not either in case of fridges); if there is more noise coming it indicates something is broken I would say

Do the pump motors begin to get more noisy fairly quickly?    
I don't believe so but I'm referring to fridges as those have similar compressors and those do not get more noisy when they get older

Our quote says cost of maintenance is 100 per year.   Is that realistic?  I note the same company is quoting 180 just for an optimising annual check.     What are you expecting your costs to be?
I'm expecting maintenance costs are 0€ until somethink breaks in the system. and if something breaks during warranty period it's still 0€ for me. If something breaks after warranty has ended I will get some compensation from insurance company (home insurance).
Only maintenance task I can imagine is to clean brine filter but should be enough you clean that once as there should not any dirt go to the closed brine circulation system after installation is once completed.
Second task is to check certain values/parameters of the system every now and then in order to see everything is fine (for example deltaTemperature between water going in and coming out, same for brine).
I assume first think to break in my nibe is "switch valve", water or brine pump, or last but not least compressor or something related to compressor. Of of course it's possible that some electrical problem occurs; there is pretty many "PWBs" in this device so likelyhood for electrical issue exists.

[Andrew]

How long would you expect a scroll compressor to last so that it was still reasonably quiet?
my nibe 1145-10 does have old type of piston compressor, but I expect it to last ten years at least, scroll might be more reliable (nibe 12kw-17kw seems to have scroll while 10kw and smaller have piston). But must say 1145-10 is very quiet, almost like fridge, and I don't expect noise level to increase during time (as it does not either in case of fridges); if there is more noise coming it indicates something is broken I would say

Do the pump motors begin to get more noisy fairly quickly?    
I don't believe so but I'm referring to fridges as those have similar compressors and those do not get more noisy when they get older

Our quote says cost of maintenance is 100 per year.   Is that realistic?  I note the same company is quoting 180 just for an optimising annual check.     What are you expecting your costs to be?
I'm expecting maintenance costs are 0€ until somethink breaks in the system. and if something breaks during warranty period it's still 0€ for me. If something breaks after warranty has ended I will get some compensation from insurance company (home insurance).
Only maintenance task I can imagine is to clean brine filter but should be enough you clean that once as there should not any dirt go to the closed brine circulation system after installation is once completed.
Second task is to check certain values/parameters of the system every now and then in order to see everything is fine (for example deltaTemperature between water going in and coming out, same for brine).
I assume first think to break in my nibe is "switch valve", water or brine pump, or last but not least compressor or something related to compressor. Of of course it's possible that some electrical problem occurs; there is pretty many "PWBs" in this device so likelyhood for electrical issue exists.

Thats interesting.  I was expecting a piston 3?KW pump motor to sound fairly industrial rather than domestic, and yes on a fridge they dont change much.  

@sailor

If a 12kw heat pump costs me 1300 per year to run i will be glad i am not paying 1900 per year.    It would be like a miracle in fact compared to the cost and mess of oil.    

[hoohöö]

Some speculation; now you consume 5000l of oil per year which is roughly 50000kwh of energy. By going to 12kw heat pump amount of purchased energy (electricity) might be max. 50% from that i.e. 25000kwh (+ electricity you consume now on yearly level, maybe around 10000kwh?). 25000kwh of electricity would cost you about 2500€ per year.
Risks in your setup is that your radiators might require pretty hot water for quite a long time of period during winter which is not good for COP (that's why I would be careful and estimate "only" 50% reduction in energy consumption)
Second risk is that in case there is long periods of colder than -10cels you would be using resistance heating which would increase amount of purchased energy.
I assume there is a possibility you would spend about 1900€ on yearly level to heating electricity if you choose ground heat with optimal pump (power) but district heating would cost about the same (at least now, prices might go higher in future but so does price of electricity as well) and district would be less risky (always enough power/heat and no quick temp.variation of radiators i.e. noise).
So would you like to have risk-free district with "lifetime agreement" or "greener" ground heating system with bit more costs and some uncertainty.
I must say I'm interested about new "toys" and currently nibe 1145 is my "toy" in addition that it keeps my house warm. District heating is pretty boring heating system.
I have checked all features there is in the pump, I have taken some log files, only thing I have not done yet is SW update of the pump, maybe I'll do that someday as well...

[Andrew]

Some speculation; now you consume 5000l of oil per year which is roughly 50000kwh of energy. By going to 12kw heat pump amount of purchased energy (electricity) might be max. 50% from that i.e. 25000kwh (+ electricity you consume now on yearly level, maybe around 10000kwh?). 25000kwh of electricity would cost you about 2500€ per year.
Risks in your setup is that your radiators might require pretty hot water for quite a long time of period during winter which is not good for COP (that's why I would be careful and estimate "only" 50% reduction in energy consumption)
Second risk is that in case there is long periods of colder than -10cels you would be using resistance heating which would increase amount of purchased energy.
I assume there is a possibility you would spend about 1900€ on yearly level to heating electricity if you choose ground heat with optimal pump (power) but district heating would cost about the same (at least now, prices might go higher in future but so does price of electricity as well) and district would be less risky (always enough power/heat and no quick temp.variation of radiators i.e. noise).
So would you like to have risk-free district with "lifetime agreement" or "greener" ground heating system with bit more costs and some uncertainty.
I must say I'm interested about new "toys" and currently nibe 1145 is my "toy" in addition that it keeps my house warm. District heating is pretty boring heating system.
I have checked all features there is in the pump, I have taken some log files, only thing I have not done yet is SW update of the pump, maybe I'll do that someday as well...

I am more concerned about global cooling after last year.   Seriously.   But yes the pump is a very interesting technology and district heating is a bit boring.   But the running costs are what matters to me because the next owner will have the cheapest heating system.

Actually i have just remembered:

1. We thought our oil consumption would be 6000 and that is what we were quoted on i thought?

2.  I measured the oil flow when it was most coldest this year at 1240l per month.     So 1240/5000 *48000 * 75%  = 8928kwh per month.  That did not include extra burner time for heating hot water though. which quote gives as 417kwh per month for total of 9345kwh

12kw heat pump produces only 10kw at 55 degrees or about -19. might be 9.75kw at -22

1. monthly heat pump power at coldest point is 7020  shortfall is 2325. monthly additional power required is about 210 euro.

3. total power is 187 + 232 =   370  per month.

4. max resistance continually running is 3.229

Which explains why at -10 only, the pump is running continuously.  It seems undersized for a winter like last year.    

Unfortunately i only have the oil useage flows/times from memory - i recall it was a bit scary!  But i did use those flows to estimate the annual consumption of 6000 i recall.

And to add another layer of complexity we used a wood stove quite often and some of the rooms were not very warm to get to the final 5000l of actual consumed oil

Thats the problem here i have no idea how much the heat pump is going to consume.

[Andrew]

I might have found the 'missing heat' for our house.

The house is a complex 'C' shape with the middle of the C only 4.4M wide and longest length of 19.3M.  The house is a mixture of one storey and two storey.  

Compared to a two storey house of the same age with 100m2 ground floor area our house requires 25% more heat assuming heat is lost equally from walls and roof

The boiler is also 42 years old.

So it appears i need a 14kw pump

[hoohöö]

So you have pretty large roof on the house; most likely adding some more insulation on roof would be pretty easy relatively low investment but would reduce heating energy consumption quite a lot, check these out;

http://www.selluvilla.net/datafiles/userfiles/Media/laskuri/main.html

http://www.selluvilla.net/?cat=12

http://www.ekovilla.com/ylapohjan-lisaeristys.php

[Andrew]

Additional insulation will make a difference but i dont have much room to work in the roof and ventilation might then become a problem.

The heat pump investment solves many problems for my house as i read it at the moment.

[justus01]

Hi, am not a professional but I think even 12kW pump could take too much energy from 200m well when it is running 24/7 and well temperature could go too low. Am I right? Hopely some professional commented that.

My lucky guess for best solution for short time period: (short payback time)
- Heat pump 12kW with internal water tank (if you don't have a bath)
- 300L puffer tank for heating
- 1 well. At least 200m.


My lucky guess for best solution for long time period: (maximum savings in long time period)
- Heat pump 15kW or 17kW (without internal water tank)
- 300L puffer tank for heating
- 300L external tank for water
- 2 wells. at least 150m each.

Our radiators need about 59 degrees at -24

Also I think some radiators could be bigger. If you change some bigger radiators you can use lower temperatures and heat pump COP is better. When you have better COP then compressor output power is bigger and you need less resistor power.

[Andrew]

Hi

I am slowly learning about this stuff.   But so far i have learnt and found out for myself, a pump described as 12kw will produce around that at 35 degrees in some kind of perfect test.  Perfectly you might get 12.8kw depending on manufacturer.   If you look up the data a pump described as 12 can be surprisingly under powered.     When it is most cold the pump produces much less than 12kw - particularly for high temp radiators when it works about 9-10kw when it is most cold outside.

A larger than required pump has an overhead on startup when it consumes a higher current to get the motor turning.  These pumps come on and off every 5 minutes or so?

Also if you have more ground well than you need then there may be pump power consumption issues that use up your expected efficiencies?

Chosing a pump therefore begins with what you require and then finding the *manufacturer* that fits your requirement since most have sizes that go in steps of say 9kw 12kw and 16kw and they want you to have a 12kw when a 14kw is what you need.

A smaller pump than you need for most cold is not a problem because these most cold periods are of small time duration and the resistance heating that comes on adds up to a fairly tiny cost compared to all the extra drilling and bigger pump and replacement costs for bigger equipment.  on the other hand if you need a 14 and you get sold a 12 where the resistance comes on at -10,    in a cold winter it will be expensive but in a average winter maybe not.    Personally i am betting on more cold winters to come for a few decades.

On changing the radiators or adding more.   I have now 20 radiators.  And i find the idea of going to underfloor heating to be the simplest option since the floor coverings are old anyway and i have concrete floors with no easy ability to put in new pipes or alter existing for many of the rooms.

[justus01]

Okey, you know quite a lot all ready about what are good things and bad thing in small systems and full power systems.

One question:
How big are your house main fuses? 3x25A or more?
3x25A could be too small with heat pump compressor and heating resistor. Specially if you have electrical stove in a sauna.

[Andrew]

Okey, you know quite a lot all ready about what are good things and bad thing in small systems and full power systems.

One question:
How big are your house main fuses? 3x25A or more?
3x25A could be too small with heat pump compressor and heating resistor. Specially if you have electrical stove in a sauna.

Good point.  We have 3x25A downstairs and then maybe 15m of cable to get to the meter and fuse box.  I was already wondering how much the lights are going to be dimming.

Therefore i am looking at the 15kw invertor pumps to prevent that

But we have a wood stove in the sauna.

Also we need maybe to move the meter to the fuses and install a new distribution box as we have a 2 wire system without separate earth on all the outlets around the house, and maybe it is easier to rewire plugged outlets from below rather than from above.

Such are the joys of house ownership!

[justus01]

Okey, you know quite a lot all ready about what are good things and bad thing in small systems and full power systems.

One question:
How big are your house main fuses? 3x25A or more?
3x25A could be too small with heat pump compressor and heating resistor. Specially if you have electrical stove in a sauna.

Good point.  We have 3x25A downstairs and then maybe 15m of cable to get to the meter and fuse box.  I was already wondering how much the lights are going to be dimming.

Therefore i am looking at the 15kw invertor pumps to prevent that

Technically inverter pump 15kW could be good choice in big radiator heated house. Maybe extra buffer tank is not needed with inverter pump, but I have notice that someone have had some problems with inverter pumps. Those inverters are quide new thing in geothermal heat pumps and there could be some design and/or software bugs. Two years ago inverter pumps was very expensive too. Maybe prices are not so high nowadays.

[Andrew]

Hi

The latest in my heat pump story is:

1. From December 2010 we stopped using the oil for heating the house and used electric heating in 90% of the rooms and recorded the kwh every day for 2 months.  The maximum kwh was no more than 9kw at -20.  

2.  Under the upper part of house we have found we have 8cm Tojax wood/air based insulation on top of the structural concrete.  In some areas under the house, if necessary, it might be possible to add more insulation under the structural concrete.  

3.  There is a 10M service tunnel for the main heating and sewage pipes that runs alongside 60% of the rooms in the house.  In these rooms the heating pipes are on top of the insulation which explains why we seemed to have underfloor heating in a few places, and probably explains why with Tojax insulation the snow melted around the foundations but did not on the brick walls.

4.  The plan is to install a heat pump at one end of the service tunnel, install underfloor heating, keep the existing radiators and install subsequently whatever additional radiators are needed.  

5.  I already have the floor removed in two of the rooms so i am hoping to get that finished before winter and ideally have the area above the service tunnel completed also.

Many thanks for all the support and guidance i have got so far

Cheers

Andrew