Ground Source Heat Pumps
Discussion
Okay, own up, who has one?
Are they any good?
Who installed it and were they any good?
Do they do what they say on the tin, or are you regretting it horribly.
We're looking in to it at the moment as a replacement for oil which is getting increasingly unpleasant.....
450sqm house, currently insulated by fresh air flowing through endless holes, will be in excess of 2010BR standards for insulation by the time we've finished with the blu-tak and expanding foam.
Are they any good?
Who installed it and were they any good?
Do they do what they say on the tin, or are you regretting it horribly.
We're looking in to it at the moment as a replacement for oil which is getting increasingly unpleasant.....
450sqm house, currently insulated by fresh air flowing through endless holes, will be in excess of 2010BR standards for insulation by the time we've finished with the blu-tak and expanding foam.
Tomoose85 said:
I work in an engineering consultancy and after a brief conversation with my engineers, the answer in 95% of cases is don't do it.
Air source heat pumps can be a good option though.
I will echo this. There are very specific situations where this will be appropriate. They are best used where you have plenty of land and gas/oil supplies are a problem.Air source heat pumps can be a good option though.
Ground source heat pumps are only efficient where the temperature difference between the input and output are low such as in underfloor heating where water temps are between 22 and 25 centigrade. They loose substantial ammounts of their efficiency if they have to supply 60 centigrade water to radiators.
In order for underfloor heating to work well you also need to have a well insulated and airtight building. Therefore it does not reccomend itself well to rennovations as the modifications to the building will need to be substantial. If you are going for pretty much a total rebuild then you may be ok.
Dont forget that you will need to dig alot of rather long trenches in the garden.
On a side note, do not even consider trying to power it with renwable energy such as wind or solar as this will simply not work as you will not be able to generate the necessary electricity cost effectively.
I've got one and I think it's great. House is warm, although lacking a focal toasty point - I will get a log burner when funds allow.
Not to expensive to run - far cheaper than oil equivalent, from the people I have spoken to, and personal experience - lots better than air source - needs less of a temp. differential to maintain efficiency.
PM me if you want to know more.
One thing, It is ideal for UFH, not so good for rads I would imagine, as the water in the pipes is only at ~24degrees to achieve an even room temp of 19degrees and it is obviously working least if you have lots of insulation (mine is as per current building regs).
Mine has been installed and running for a year, and have been over the moon with it.
Danfoss heat pump, running wet UFH throughout.
All the best
Tom
Not to expensive to run - far cheaper than oil equivalent, from the people I have spoken to, and personal experience - lots better than air source - needs less of a temp. differential to maintain efficiency.
PM me if you want to know more.
One thing, It is ideal for UFH, not so good for rads I would imagine, as the water in the pipes is only at ~24degrees to achieve an even room temp of 19degrees and it is obviously working least if you have lots of insulation (mine is as per current building regs).
Mine has been installed and running for a year, and have been over the moon with it.
Danfoss heat pump, running wet UFH throughout.
All the best
Tom
A well designed heat pump system will have the lowest running cost in terms of energy - achieving this end in an existing property can be difficult to impossible and expensive.
If you want more information post it here, I lived in Coventry for many years and now supply and install underfloor heating systems with air sourced heat pumps in New Zealand.
If you want more information post it here, I lived in Coventry for many years and now supply and install underfloor heating systems with air sourced heat pumps in New Zealand.
The floor area of my place is around 100m^2, half of it full height if that makes I have an 8kW heat pump (from memory) I will check specifics if anyone wants me to. The place is always at a comfortable temperature, lounges etc ~19degrees, bedroom slightly below, and bathrooms above.
I have 300m of collector pipe buried in a 150m long trench, 1m wide - with the pipe on each edge of the trench.
Costs probably on average £65 a month all year round for electric - the only problem is that I would be screwed if I had a considerable power cut, but hasn't happened.
Even when the air temp is well below zero, the house maintains temp.
Depending where you're based, you're more than welcome to come have a look for yourself - I'm in Oswestry, Shropshire. I went to see a place with it up and running before I signed on the dotted line, and my mind was made up!
Tom
I have 300m of collector pipe buried in a 150m long trench, 1m wide - with the pipe on each edge of the trench.
Costs probably on average £65 a month all year round for electric - the only problem is that I would be screwed if I had a considerable power cut, but hasn't happened.
Even when the air temp is well below zero, the house maintains temp.
Depending where you're based, you're more than welcome to come have a look for yourself - I'm in Oswestry, Shropshire. I went to see a place with it up and running before I signed on the dotted line, and my mind was made up!
Tom
Edited by tom_loughlin on Monday 24th January 19:17
Thanks Tom, did you dig the trenches, run the pipe etc yourself?. What make of heat pump do you have, i've been looking at the Nibe models, seem to be well proven. Will you quality for the RHI tariffs when introduced?. WOuld you mind PMing me with the costs if you dont want to post, have had a quote for a full system and its a bit eye watering so would like to compare!
Craig W said:
You need huge areas for the coils to be stretched out.
Boreholes overcome the need to have lots of land.But boreholes are expensive, especially just a one-off.
A good ground source unit will be 400%+ efficient. i.e use 1kw electricity to run it get 4+kw of heat out. An oil boiler is about 85% efficient.
Air sources are more efficient in warmer weather but still produce enough heat for underfloor heating in the UK winter, but in extremely cold they loose efficiency down to near 100%.
hahithestevieboy said:
Tomoose85 said:
I work in an engineering consultancy and after a brief conversation with my engineers, the answer in 95% of cases is don't do it.
Air source heat pumps can be a good option though.
I will echo this. There are very specific situations where this will be appropriate. They are best used where you have plenty of land and gas/oil supplies are a problem.Air source heat pumps can be a good option though.
Ground source heat pumps are only efficient where the temperature difference between the input and output are low such as in underfloor heating where water temps are between 22 and 25 centigrade. They loose substantial ammounts of their efficiency if they have to supply 60 centigrade water to radiators.
In order for underfloor heating to work well you also need to have a well insulated and airtight building. Therefore it does not reccomend itself well to rennovations as the modifications to the building will need to be substantial. If you are going for pretty much a total rebuild then you may be ok.
Dont forget that you will need to dig alot of rather long trenches in the garden.
On a side note, do not even consider trying to power it with renwable energy such as wind or solar as this will simply not work as you will not be able to generate the necessary electricity cost effectively.
Temps hit -19 three times in december, and the locals with ASHP were all cursing and freezing as their units had frozen solid, or were operating at 2kw leccy for every 1kw of heat.
There will be UFH on both ground and 1st floors, the house currently has unfilled cavity walls and will end up with filled cavities, triple glazing and then an external layer of celotex before the final wood cladding - we will be well in excess of 2010BR by then... hopefully.
All I'm thinking is we have now done the calcs and it seems to make sense from a financial point of view in terms of break even points etc, I just still remain to be convinced of the efficacy of such things and whether they actually do what they say on the tin...
tom_loughlin said:
The floor area of my place is around 100m^2, half of it full height if that makes I have an 8kW heat pump (from memory) I will check specifics if anyone wants me to. The place is always at a comfortable temperature, lounges etc ~19degrees, bedroom slightly below, and bathrooms above.
I have 300m of collector pipe buried in a 150m long trench, 1m wide - with the pipe on each edge of the trench.
Costs probably on average £65 a month all year round for electric - the only problem is that I would be screwed if I had a considerable power cut, but hasn't happened.
Even when the air temp is well below zero, the house maintains temp.
Depending where you're based, you're more than welcome to come have a look for yourself - I'm in Oswestry, Shropshire. I went to see a place with it up and running before I signed on the dotted line, and my mind was made up!
Tom
Sounds ace tom, could you include me on the PM of costs if you wouldn't mind? I'm in Worcestershire, so not a million miles away if you're sure you're okay for me to bend your ear over a coffee?I have 300m of collector pipe buried in a 150m long trench, 1m wide - with the pipe on each edge of the trench.
Costs probably on average £65 a month all year round for electric - the only problem is that I would be screwed if I had a considerable power cut, but hasn't happened.
Even when the air temp is well below zero, the house maintains temp.
Depending where you're based, you're more than welcome to come have a look for yourself - I'm in Oswestry, Shropshire. I went to see a place with it up and running before I signed on the dotted line, and my mind was made up!
Tom
Edited by tom_loughlin on Monday 24th January 19:17
RedLeicester said:
hahithestevieboy said:
Tomoose85 said:
I work in an engineering consultancy and after a brief conversation with my engineers, the answer in 95% of cases is don't do it.
Air source heat pumps can be a good option though.
I will echo this. There are very specific situations where this will be appropriate. They are best used where you have plenty of land and gas/oil supplies are a problem.Air source heat pumps can be a good option though.
Ground source heat pumps are only efficient where the temperature difference between the input and output are low such as in underfloor heating where water temps are between 22 and 25 centigrade. They loose substantial ammounts of their efficiency if they have to supply 60 centigrade water to radiators.
In order for underfloor heating to work well you also need to have a well insulated and airtight building. Therefore it does not reccomend itself well to rennovations as the modifications to the building will need to be substantial. If you are going for pretty much a total rebuild then you may be ok.
Dont forget that you will need to dig alot of rather long trenches in the garden.
On a side note, do not even consider trying to power it with renwable energy such as wind or solar as this will simply not work as you will not be able to generate the necessary electricity cost effectively.
Temps hit -19 three times in december, and the locals with ASHP were all cursing and freezing as their units had frozen solid, or were operating at 2kw leccy for every 1kw of heat.
There will be UFH on both ground and 1st floors, the house currently has unfilled cavity walls and will end up with filled cavities, triple glazing and then an external layer of celotex before the final wood cladding - we will be well in excess of 2010BR by then... hopefully.
All I'm thinking is we have now done the calcs and it seems to make sense from a financial point of view in terms of break even points etc, I just still remain to be convinced of the efficacy of such things and whether they actually do what they say on the tin...
The old's have more or less finished building their place. I visited recently, and it couldn't have been colder outside.
They use 6kW (I think) to heat their place from a borehole, and it's never cold inside. I found it odd actually. It was even warm at night. Hot water was in instant copious supply at any time.
The building has to be designed from the ground up with this sort of heating in mind, and it makes build costs significantly higher.
They use 6kW (I think) to heat their place from a borehole, and it's never cold inside. I found it odd actually. It was even warm at night. Hot water was in instant copious supply at any time.
The building has to be designed from the ground up with this sort of heating in mind, and it makes build costs significantly higher.
Edited by dilbert on Tuesday 25th January 02:35
We've just (October) bought a property back in the UK with one. GSHP was installed for the vendor, though he did the installation of the coils under the garden himself.
Floor area is about ~320 sq.m over three floors, with the house being ~50% 1750-1800 refurbished (i.e. solid stone walls, lime plaster, single glazed leaded windows) and ~50% being 2005-2007 new build but done in traditional style (i.e. cavity walls, but single glazed leaded windows). The GSHP provides underfloor heating to all three floors (ground floor being solid (stone flags) and upper two floors being oak) and also contributes hot water, supplemented by an electric immersion heater.
The old/new build split clearly illustrates the importance/benefits of the GSHP/underfloor combination being designed in from the start. The new build part of the house is kept more than comfortably warm by the low temp (~20C) underfloor, whereas the older part of the house does need the extra heat from an AGA and a log-burner to feel really warm.
In terms of installation costs and and specs, I can get SHMBO to dig out the details if that would be useful. On running costs, it's early days - but I would say costs are currently running higher than we had anticipated but it's hard to tell what the benefit over a year might be given the amount of frost and snow we've had (overnight down to -15C).
Floor area is about ~320 sq.m over three floors, with the house being ~50% 1750-1800 refurbished (i.e. solid stone walls, lime plaster, single glazed leaded windows) and ~50% being 2005-2007 new build but done in traditional style (i.e. cavity walls, but single glazed leaded windows). The GSHP provides underfloor heating to all three floors (ground floor being solid (stone flags) and upper two floors being oak) and also contributes hot water, supplemented by an electric immersion heater.
The old/new build split clearly illustrates the importance/benefits of the GSHP/underfloor combination being designed in from the start. The new build part of the house is kept more than comfortably warm by the low temp (~20C) underfloor, whereas the older part of the house does need the extra heat from an AGA and a log-burner to feel really warm.
In terms of installation costs and and specs, I can get SHMBO to dig out the details if that would be useful. On running costs, it's early days - but I would say costs are currently running higher than we had anticipated but it's hard to tell what the benefit over a year might be given the amount of frost and snow we've had (overnight down to -15C).
dilbert said:
The old's have more or less finished building their place. I visited recently, and it couldn't have been colder outside.
They use 6kW (I think) to heat their place from a borehole, and it's never cold inside. I found it odd actually. It was even warm at night. Hot water was in instant copious supply at any time.
The building has to be designed from the ground up with this sort of heating in mind, and it makes build costs significantly higher.
Funnily enough, this is one of the things that worries me - if it's warm at night, I'm sleeping outside! I know women have the constitution of dinosaurs and other lizards, but if I'm too hot I can't settle. So I want upstairs to be warm at bed time, but not constantly....They use 6kW (I think) to heat their place from a borehole, and it's never cold inside. I found it odd actually. It was even warm at night. Hot water was in instant copious supply at any time.
The building has to be designed from the ground up with this sort of heating in mind, and it makes build costs significantly higher.
Edited by dilbert on Tuesday 25th January 02:35
RedLeicester said:
Thanks chap, would be very interested to see some costings.
Prices were:8,560 Nibe Fighter 1240-8kW GSHP, 400m Ground Loop
7,300 Internal Fastflo pipes, cliptrack, manifolds, valves etc. for installation of UFH (320 sq.m floor area)
All supplied by Nu-Heat on a supply-only basis.
Ground loop installed by property vendor himself
GSHP installation by local contractors: Wilson Heating
GSHP commissioning by: Nu-Heat
Subsequent servicing (annual to maintain the 10yr warranty) by another local: Wrekin Heating Services
Don't have the prices of the installation, but understand the total was close to 20k before the benefit of some grants which reduced that a bit (though they had to be repaid as the vendor sold so soon).
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