Heat pumps

[millrace]

If your 25yrs old, and can go whole hog, ie solar, heat pump  fully insulated basically passive standard crack on you will over your lifetime see advantages,, how ever! If like myself almost 50 there is no way on earth i would ever see break even on any of this green upgrades, infact i can only see in my future if im lucky enough to retire, being faced with having to potentially sell my house as ive no idea how im meant to afford what this government is pushing on to us!!

[Humblepie]

Had one installed along with solar panels around 2 and half years ago. Was previously on LPG and costing a fortune. The install cost was high (around £18k) but we qualified for a payback scheme so receive £430 per quarter for seven years, around 66% of the original cost. Very little disruption in the house during the install, a couple of bigger radiators and a new tank.

Until the electricity prices went mad, we were quids in and the performance of it has been very good indeed throughout all seasons.

Now thinking about getting battery storage for the solar panels but will wait to see what happens with the electricity prices before doing so as the cost for them is around £7k

 

[JohnfromUK]

Lots of good information here so far.  Some key points are;

• what type of house - and specifically how well insulated it is/can be made to be - is critical
• what type of energy sources you have access to
• what type of heating you have now will influence any prospective saving to be made
• and finally one not yet mentioned - space outside

On point 1, any well insulated house will be economical to heat - whatever fuel source is used.  With a heat pump, as has been pointed out, running for long periods (or even continuous) is needed because the temperature of the fluid is relatively low compared to other forms of energy.  That works best in a very well insulated building and suits underfloor type heating, or needs very large sized radiators in a non underfloor system.  May also appeal if the building is always occupied (i.e. at home all day).  It is difficult to bring the insulation of older properties up to best modern standards since they tend to rely on much higher ventilation to prevent damp and condensation and things like spray foam insulation can cause huge problems by restricting air flow that is essential to keeping the fabric dry.

On point 2, heatpumps use electricity which is typically an expensive form of energy.  Mains gas is around 1/3 of the price per KWh compared to electricity.  Oil and liquefied gas vary more, but fall in betweeen.  Various solar/wind/storage etc. schemes can make electricity cheaper, but are usually expensive to buy/install.  Storing warmth as warm water in a thermal store can take advantage of off peak and otherwise surplus electricity pricing and can work with a heatpump - but adds cost and needs a lot of space.

On point 3, unless you have underfloor heating now, a traditional radiator system will probably need to be upgraded with bigger radiators and pipes because the water temperatures from a heatpump are so much lower.  This can be costly and difficult to achieve 'domestically'.  Similarly, if you currently have a combi boiler, some alternative (usually a water cylinder) will be needed.  This takes up space and will involve plumbing changes.

On point 4, they do take up a bit of outside space - and make some noise when operating.  Worth considering if you are limited in outside space.

[Old farrier]

Very interesting stuff a few questions 

which would be best suited for a new build 

ground or air source heat pump 

solar panels how many would be needed to power it assuming that would be enough or would it need a battery pack backup? 
 

im sure I should be asking more questions but very limited knowledge on this subject 

trying to educate myself here 🤔

[JohnfromUK]

5 minutes ago, Old farrier said:

Very interesting stuff a few questions 

which would be best suited for a new build 

ground or air source heat pump 

solar panels how many would be needed to power it assuming that would be enough or would it need a battery pack backup? 
 

im sure I should be asking more questions but very limited knowledge on this subject 

trying to educate myself here 🤔

which would be best suited for a new build ground or air source heat pump 

Ground source needs either (a) quite a large area (700 sq metres) with a pipe array buried under the ground - see here https://www.imsheatpumps.co.uk/blog/how-much-space-needed-for-ground-source-heat-pump-gshp/

or (b) a vertical bore hole type around 100 m deep (also in article above).  These are both expensive, but weather independent (because the ground temperature changes so little).  A 'better' system, but a lot more expensive.  A lot of digging is involved and so will spoil any existing garden and cannot be done where there are too many tree roots.  Best if you have a field/paddock - or even better a lake or decent running stream.

Air sourced is cheaper, but more subject to reduced performance in cold weather, and typically a bit noisier.  It needs only a small amount of outside space

solar panels how many would be needed to power it assuming that would be enough or would it need a battery pack backup?

There is no straight answer to this.  Bigger heatpumps need more panels, but it will not be trivial - and they will need to use mains power anyway (though it is cheaper at night).  Battery back up enables you to store power you generate.  IF you had a heat pump and used the power in real time as it was generated, you would not need batteries.  Power stored by batteries from solar is often used at night (no solar!) but worth remembering - power is cheaper at hight anyway on off peak.  It would not 'need' a battery, but it might save more - but would have high initial cost. 

[scarecrow243]

we live in an old cottage and we have the big water tank  and ten solar panels on the roof  we have bigger radiators installed  using the same pipes we do have constant hot water  but we have hardly used the heating as its been warm  we don't have any batteries any electric we don't use goes back to the grid

[B725]

Someone correct me if I am wrong uk domestic solar is limited to 3.6kw. I have a 6kw system with battery so I can't see solar on its own would be enough to power the ashp bearing in mind the limited sunlight in the UK winter. This is a screen shot of mine today and it's a bright sunny day 

[Old farrier]

4 minutes ago, JohnfromUK said:

which would be best suited for a new build ground or air source heat pump 

Ground source needs either (a) quite a large area (700 sq metres) with a pipe array buried under the ground - see here https://www.imsheatpumps.co.uk/blog/how-much-space-needed-for-ground-source-heat-pump-gshp/

or (b) a vertical bore hole type around 100 m deep (also in article above).  These are both expensive, but weather independent (because the ground temperature changes so little).  A 'better' system, but a lot more expensive.  A lot of digging is involved and so will spoil any existing garden and cannot be done where there are too many tree roots.  Best if you have a field/paddock - or even better a lake or decent running stream.

Air sourced is cheaper, but more subject to reduced performance in cold weather, and typically a bit noisier.  It needs only a small amount of outside space

solar panels how many would be needed to power it assuming that would be enough or would it need a battery pack backup?

There is no straight answer to this.  Bigger heatpumps need more panels, but it will not be trivial - and they will need to use mains power anyway (though it is cheaper at night).  Battery back up enables you to store power you generate.  IF you had a heat pump and used the power in real time as it was generated, you would not need batteries.  Power stored by batteries from solar is often used at night (no solar!) but worth remembering - power is cheaper at hight anyway on off peak.  It would not 'need' a battery, but it might save more - but would have high initial cost. 

Thank you for the info very informative 

I have a large paddock 5acres and a stream and a marsh although a long distance from the new house probably to far for any benefit 

[B725]

When I was still at work we had a problem with ground source heating at a school, it required a new part that had to come from Germany it took 7 months to arrive, the school had gas boilers as a back up and did not want the gsh repaired as they saved over £3k in electric. 

[12gauge82]

8 minutes ago, B725 said:

Someone correct me if I am wrong uk domestic solar is limited to 3.6kw. I have a 6kw system with battery so I can't see solar on its own would be enough to power the ashp bearing in mind the limited sunlight in the UK winter. This is a screen shot of mine today and it's a bright sunny day 

I believe it's 4kw, anything more than that and you need to apply to the grid and your property gets classed as a power generating facility and grant is dependent on the grid being able to handle it, transformers, flicker ect.

Air source heating absolutely does work, but a decent set up relies on a very well insulated property and ideally having underfloor heating and solar panels. To make a saving over mains gas is tough, although not impossible, but the initial out lay will be substantially more.

I have a set up where I pay little more than the standing charge, but despite having a property that would be classed as a good candidate for a heat pump, I've installed other options which I believe suit me far better.

[Weihrauch17]

2 hours ago, millrace said:

If your 25yrs old, and can go whole hog, ie solar, heat pump  fully insulated basically passive standard crack on you will over your lifetime see advantages,, how ever! If like myself almost 50 there is no way on earth i would ever see break even on any of this green upgrades, infact i can only see in my future if im lucky enough to retire, being faced with having to potentially sell my house as ive no idea how im meant to afford what this government is pushing on to us!!

95% can't.

[B725]

[old man]

4 hours ago, millrace said:

If your 25yrs old, and can go whole hog, ie solar, heat pump  fully insulated basically passive standard crack on you will over your lifetime see advantages,, how ever! If like myself almost 50 there is no way on earth i would ever see break even on any of this green upgrades, infact i can only see in my future if im lucky enough to retire, being faced with having to potentially sell my house as ive no idea how im meant to afford what this government is pushing on to us!!

Again, the general idea? Keep the population on the back foot, scared and compliant? Easier to push around at the will of whoever is driving the madness?

[Yellow Bear]

2 hours ago, JohnfromUK said:

which would be best suited for a new build ground or air source heat pump 

Ground source needs either (a) quite a large area (700 sq metres) with a pipe array buried under the ground - see here https://www.imsheatpumps.co.uk/blog/how-much-space-needed-for-ground-source-heat-pump-gshp/

or (b) a vertical bore hole type around 100 m deep (also in article above).  These are both expensive, but weather independent (because the ground temperature changes so little).  A 'better' system, but a lot more expensive.  A lot of digging is involved and so will spoil any existing garden and cannot be done where there are too many tree roots.  Best if you have a field/paddock - or even better a lake or decent running stream.

Air sourced is cheaper, but more subject to reduced performance in cold weather, and typically a bit noisier.  It needs only a small amount of outside space

solar panels how many would be needed to power it assuming that would be enough or would it need a battery pack backup?

There is no straight answer to this.  Bigger heatpumps need more panels, but it will not be trivial - and they will need to use mains power anyway (though it is cheaper at night).  Battery back up enables you to store power you generate.  IF you had a heat pump and used the power in real time as it was generated, you would not need batteries.  Power stored by batteries from solar is often used at night (no solar!) but worth remembering - power is cheaper at hight anyway on off peak.  It would not 'need' a battery, but it might save more - but would have high initial cost. 

2 things to add -

where you are on the IoW you are subject to salt laden air which plays havoc with the thin Ali fins on air source reducing life span.   People will deny this but I have had experience of it.

with more moving parts, refrigerant gas requirements, and lower numbers about maintenance costs are much higher (although this may change with time.)

[sandspider]

8 hours ago, 12gauge82 said:

I believe it's 4kw, anything more than that and you need to apply to the grid and your property gets classed as a power generating facility and grant is dependent on the grid being able to handle it, transformers, flicker ect.

Air source heating absolutely does work, but a decent set up relies on a very well insulated property and ideally having underfloor heating and solar panels. To make a saving over mains gas is tough, although not impossible, but the initial out lay will be substantially more.

I have a set up where I pay little more than the standing charge, but despite having a property that would be classed as a good candidate for a heat pump, I've installed other options which I believe suit me far better.

Go on then, what have you installed?

[12gauge82]

8 minutes ago, sandspider said:

Go on then, what have you installed?

I've installed 12kw of solar with battery, a 1000 Litre heat store and a log burner which are all connected together.

During the summer the solar covers all my eletric and also keeps the 1000L tank at full heat via twin emersion heaters at zero cost, the heat store then supply's all the hot water and heating via underfloor I could ever need and the spare capacity ensures there's plenty in reserve even if we have a cloudy week.

During the winter, the solar still supplies plenty of eletric and most of the hot water, if we have a cloudy spell, a free supply of wood allows me to heat the entire house, as burning wood heats 2 rooms via a double sided fire but the real magic is most of the heat, warms up the heat store which warms the entire house via underfloor heating.

I have a gas fired boiler which would only kick in as a last resort if the sun didn't shine for an extended period and I didn't have any wood to burn, but the heat store is set up so that it only kicks in as a very last resort, it's probably a bit technical to explain on here, although I'll give it a go if your interested.

[sandspider]

Thanks. I like the sound of that, and that's the sort of system I'd like to do if I ever did a new one. But our oil boiler is fairly recent, and log boilers (or even log stoves with back boilers) don't seem to be common / popular anymore. Shame, as log burners, solar and a big heat store do make a lot of sense.

[Humblepie]

12 hours ago, JohnfromUK said:

Air sourced is cheaper, but more subject to reduced performance in cold weather, and typically a bit noisier.  It needs only a small amount of outside space

Haven’t noticed any reduced performance in cold weather and the system is guaranteed to work down to -25 degrees. The air pump is not noisy at all unless you stand right next to it and then it is just a gentle hum when the fan is turning

 

10 hours ago, old man said:

Again, the general idea? Keep the population on the back foot, scared and compliant? Easier to push around at the will of whoever is driving the madness?

Agree with this comment about whoever is driving this madness. We got our system installed as it was the cheapest in the long run with the options we had and nothing to do with the net zero lunatics. I am also all for fossil fuels rather than electric everything. We have a multi fuel burner as well in which I use to burn coal and wood. 

 

13 hours ago, JohnfromUK said:

On point 3, unless you have underfloor heating now, a traditional radiator system will probably need to be upgraded with bigger radiators and pipes because the water temperatures from a heatpump are so much lower.  This can be costly and difficult to achieve 'domestically'.  Similarly, if you currently have a combi boiler, some alternative (usually a water cylinder) will be needed.  This takes up space and will involve plumbing changes.

as mentioned previously, we only had to have two slightly bigger rads fitted and the existing pipe work was used. For info our house is a 1930’s bungalow and the 2 new rads were in the new extension we had build in 2015. Our existing cylinder was replaced and obviously the plumbing as well for this but it fitted in the same cupboard. You are correct that underfloor heating is a better bet rather than rads but we have had no problems with with the heating at all
 

[12gauge82]

6 hours ago, sandspider said:

Thanks. I like the sound of that, and that's the sort of system I'd like to do if I ever did a new one. But our oil boiler is fairly recent, and log boilers (or even log stoves with back boilers) don't seem to be common / popular anymore. Shame, as log burners, solar and a big heat store do make a lot of sense.

My energy bills are non existent, the only issue was finding someone qualified to fit it all as a log burner (uncontrolled heat source) connected to a unvented cylinder would normally equal a bomb, there's obviously a bit of work involved in designing safety systems to ensure that can't happen.

[JohnfromUK]

8 hours ago, Humblepie said:

Haven’t noticed any reduced performance in cold weather and the system is guaranteed to work down to -25 degrees. The air pump is not noisy at all unless you stand right next to it and then it is just a gentle hum when the fan is turning

You probably have a better designed system than many around and good insulation.  I walk (dog walking) past a modern 'high spec' house most days.  Cold weather the heat pump is very noticeable walking past in the road - not noisy, but noticeable in a quiet road maybe 20 feet away.  It rarely seems to run except in cold weather, but I do know they house is very high spec.

8 hours ago, Humblepie said:

as mentioned previously, we only had to have two slightly bigger rads fitted and the existing pipe work was used. For info our house is a 1930’s bungalow and the 2 new rads were in the new extension we had build in 2015

I fully replumbed (every pipe and radiator replaced) my house around 6 years ago now and put in oversized radiators (mainly double convectors instead of singles) and pipework - mainly to allow best efficiency with a condensing gas boiler (I have mains gas which was a 'no brainer' then) but also with an eye to possible future proofing.  Underfloor was not practical to use in my (fairly large, old and listed) building.  My system works well with a flow temperature of around 50C, but needs a little more (maybe 60C?) when very cold and windy.  There are a few places (notably the kitchen) where space for bigger radiators was not available.

A plus with the bigger but cooler radiators is that the heat feels less 'stuffy' and more naturally warm.

[sandspider]

4 hours ago, 12gauge82 said:

My energy bills are non existent, the only issue was finding someone qualified to fit it all as a log burner (uncontrolled heat source) connected to a unvented cylinder would normally equal a bomb, there's obviously a bit of work involved in designing safety systems to ensure that can't happen.

I burn a lot of wood, free ish apart from my time and fuel. But woodburners only, a lot simpler to install than log boilers and heat stores. Would be nice if they warmed the bedrooms as well as downstairs though, but that would need pipework, tanks, valves etc.

Does your tank pressure release flow into your cold water tank?

[12gauge82]

11 minutes ago, sandspider said:

I burn a lot of wood, free ish apart from my time and fuel. But woodburners only, a lot simpler to install than log boilers and heat stores. Would be nice if they warmed the bedrooms as well as downstairs though, but that would need pipework, tanks, valves etc.

Does your tank pressure release flow into your cold water tank?

No the hot water is completely separate and although technically very different, it delivers hot water much like a mega flow or other unvented cylinder. It's a very technical biy of kit that basically allows you to store up any energy  produced, a bit like a giant battery but full of hot water and then powers all hot water needs including taps and heating.

The tank is stratified which ensures hot water rises into a separate part of the tank, ensuring there is always usable hot water in the top instead of a 1000L at say 35c I'll have 300L in the top at 70c, once the entire tank is hot, the cold water feed goes through a wound copper pipe starting at the bottom which heats as it goes up the tank, which means heat is taken from the bottom first, which stops the gas boiler kicking in until the entire tank is cold (very rarely happens and hasn't happened since February last year).

I think it's a brilliant system and has certainly saved me a vast amount of money compared to a heat pump and is probably comparable in cost to install.

[sandspider]

👍👍

[old man]

On 23/09/2023 at 23:06, Humblepie said:

Haven’t noticed any reduced performance in cold weather and the system is guaranteed to work down to -25 degrees. The air pump is not noisy at all unless you stand right next to it and then it is just a gentle hum when the fan is turning

 

Agree with this comment about whoever is driving this madness. We got our system installed as it was the cheapest in the long run with the options we had and nothing to do with the net zero lunatics. I am also all for fossil fuels rather than electric everything. We have a multi fuel burner as well in which I use to burn coal and wood. 

 

as mentioned previously, we only had to have two slightly bigger rads fitted and the existing pipe work was used. For info our house is a 1930’s bungalow and the 2 new rads were in the new extension we had build in 2015. Our existing cylinder was replaced and obviously the plumbing as well for this but it fitted in the same cupboard. You are correct that underfloor heating is a better bet rather than rads but we have had no problems with with the heating at all
 

Net zero, another introduction to modern slavery?

[discobob]

10 minutes ago, old man said:

Net zero, another introduction to future slavery?

Fixed it for you