- Location
- Wiltshire
Have the chimney I am quite good at setting it on fire
Slight problems with 2 foot thick walls, lath and plaster walls and the listing make everything tricky
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Can air or ground source heat pumps work in old buildings?
- Thread starter Jerry
- Start date
Have the chimney I am quite good at setting it on fire
Slight problems with 2 foot thick walls, lath and plaster walls and the listing make everything tricky
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What he said about internal lining with insulation and new plasterboard. Our house has 18” solid stone walls, I battened all external facing walls with 2x2 battens every 15 “ or so and infilled between with Kingspan and then plasterboarded over. House is 4 bed detached and has oil fired aga and oil central heating. Average oil consumption for both AGA and boiler has been 11 litres per day over last 15 years.
Recently changed boiler to more modern condensing boiler, had thought about ground source or air source but economics just didn’t stack up.
Alchad
renewablejohn
Member
- Location
- lancs
Can be done but being listed you will need to get approval and understand how much work it entails. Our farmhouse is a lot older approx 1650 with thick stone walls and stone mullions. Our aim slightly different to heat all the house with Dunsley Yorkshire biomass stove. To achieve this priorities have been insulation and air sealed. Grade 2 listed so all had to approved before work started. Main points all windows replaced with triple glaze non opening, ground floors insulated wth foamed glass and UFH installed. Doors replaced with outward opening scandinavian sealed units. Fireplaces with external air source. Then MVHR to get the building to breath.
- Location
- Shropshire
Wow, proper job!
Thought the listing/conservation people didn’t like windows to be anything other than single glazed.
renewablejohn
Member
- Location
- lancs
Listing/conservation officers do as there told if you have English Heritage fighting your corner and telling them how a historic building can be brought into the 21st century by reinstating a lot of historic features originally lost. ie took out modern windows and reinstalled stone mullions with glass direct into the stone mullions the fact it was triple glazed was not a problem for English Heritage. The Listing/conservation officer was after oak frames with single glass panes.
- Location
- Carmarthenshire, West Wales
Can't you drill a bore hole, I am sure I heard that is better
Lincs Lass
Member
- Location
- north lincs
Maybe could do , everytime Ive seen it done ,,they are burying pipes in deep trenches ,,like underfloor heating on a much larger scale
I'd like to caveat my response in advance; I work for a heat pump system design consultancy so I am probably a little biased on this matter, but I also consider myself quite well informed.
The biggest misconception about heat pumps is that they will not be able to cope in old or poorly insulated houses. Heat is heat, no matter how it is produced. If you have a poorly insulated house then you will need to supply more heat than if you have a well insulated house, irrespective of what heating system you have. Insulating your house, where possible, may be a cheap way of reducing your heating demand and therefore the size of the installation but again that applies to all heating systems.
Unlike fossil fuels, heat pumps are unfortunately quite expensive to install. With a gas boiler for example it doesn't really cost much more to install a much larger boiler than necessary so people tend to install systems with lots of redundancy. With a heat pump it does cost proportionately more to install larger systems and so installers may try to install as small a system as possible to reduce the upfront cost (you sometimes see what is rated as a 15 kW heat pump which is actually a 12 kW heat pump with a 3 kW immersion heater). This is where I believe the reputation for heat pumps not being able to cope has come from, basically people not putting a big enough one in or sizing the system properly.
With respect to heat emitters: Heat pumps work more efficiently at lower flow temperatures. It may be that the radiators in your house are currently over sized (usually the case) and so would be able to cope with lower flow temperatures in which case great you can run the heat pump at say 55C. If they are undersized you can replace one or two in the area that is struggling to be heated or alternatively run the heat pump at a higher temperature (note this will increase running costs.) For about £500 someone should be able to come and do a heat loss and heat emitter survey of your property which will allow them to calculate how much heat certain areas will require and what flow and return temperatures you can operate the heat pump at. If you are considering a heat pump then this is really worth doing as it will be necessary at the later design stages anyway to ensure an efficient system that works properly. Again this is one of the crucial steps that a lot of people don't do and then complain when their system doesn't work properly.
With regards to running costs, if you have the land then a horizontal collector GSHP will be the 'best' solution, in that it is cheaper to install than vertical boreholes and much more efficient than an ASHP. Having said that, it will be more expensive to install than an ASHP so do your homework/consult a professional as to whether this is worth it or not for you. On this note, It is important to take manufacturer stated COPs with a pinch of salt, especially for ASHPs as they will always be calculated under perfect conditions and usually at quite low flow temperatures. Also be aware of the difference between COP and Seasonal COP (SCOP). COP is the instantaneous measure of heat produced per kwh of electricity used, this will vary depending on the source and load temperatures. SCOP is the efficiency throughout the year and will take into account defrost cycles and periods when the outside air temperature is very low and therefore COP is much lower.
For example for 55/45C flow and return temperatures, expect SCOPs closer to 2.5 for an ASHP and 3.5 for a GSHP. This is obviously a very rough rule of thumb but hopefully should prevent you from getting sucked into purchasing an ASHP that claims a SCOP of 5 or something ridiculous.
I hope this is vaguely helpful and not too divisive. I am sure there will be people who can provide stories of how a heat pump has not worked out for them and I don't doubt them but I just wanted to rectify the argument that heat pumps can't cope with old or poorly insulated buildings. With gas as cheap as it is, heat pumps might not always be the most cost-effective solution but they will be possible.
Not a sales ploy, but if you have any questions and want to get in touch directly I'd be more than happy to help where I can.
The biggest misconception about heat pumps is that they will not be able to cope in old or poorly insulated houses. Heat is heat, no matter how it is produced. If you have a poorly insulated house then you will need to supply more heat than if you have a well insulated house, irrespective of what heating system you have. Insulating your house, where possible, may be a cheap way of reducing your heating demand and therefore the size of the installation but again that applies to all heating systems.
Unlike fossil fuels, heat pumps are unfortunately quite expensive to install. With a gas boiler for example it doesn't really cost much more to install a much larger boiler than necessary so people tend to install systems with lots of redundancy. With a heat pump it does cost proportionately more to install larger systems and so installers may try to install as small a system as possible to reduce the upfront cost (you sometimes see what is rated as a 15 kW heat pump which is actually a 12 kW heat pump with a 3 kW immersion heater). This is where I believe the reputation for heat pumps not being able to cope has come from, basically people not putting a big enough one in or sizing the system properly.
With respect to heat emitters: Heat pumps work more efficiently at lower flow temperatures. It may be that the radiators in your house are currently over sized (usually the case) and so would be able to cope with lower flow temperatures in which case great you can run the heat pump at say 55C. If they are undersized you can replace one or two in the area that is struggling to be heated or alternatively run the heat pump at a higher temperature (note this will increase running costs.) For about £500 someone should be able to come and do a heat loss and heat emitter survey of your property which will allow them to calculate how much heat certain areas will require and what flow and return temperatures you can operate the heat pump at. If you are considering a heat pump then this is really worth doing as it will be necessary at the later design stages anyway to ensure an efficient system that works properly. Again this is one of the crucial steps that a lot of people don't do and then complain when their system doesn't work properly.
With regards to running costs, if you have the land then a horizontal collector GSHP will be the 'best' solution, in that it is cheaper to install than vertical boreholes and much more efficient than an ASHP. Having said that, it will be more expensive to install than an ASHP so do your homework/consult a professional as to whether this is worth it or not for you. On this note, It is important to take manufacturer stated COPs with a pinch of salt, especially for ASHPs as they will always be calculated under perfect conditions and usually at quite low flow temperatures. Also be aware of the difference between COP and Seasonal COP (SCOP). COP is the instantaneous measure of heat produced per kwh of electricity used, this will vary depending on the source and load temperatures. SCOP is the efficiency throughout the year and will take into account defrost cycles and periods when the outside air temperature is very low and therefore COP is much lower.
For example for 55/45C flow and return temperatures, expect SCOPs closer to 2.5 for an ASHP and 3.5 for a GSHP. This is obviously a very rough rule of thumb but hopefully should prevent you from getting sucked into purchasing an ASHP that claims a SCOP of 5 or something ridiculous.
I hope this is vaguely helpful and not too divisive. I am sure there will be people who can provide stories of how a heat pump has not worked out for them and I don't doubt them but I just wanted to rectify the argument that heat pumps can't cope with old or poorly insulated buildings. With gas as cheap as it is, heat pumps might not always be the most cost-effective solution but they will be possible.
Not a sales ploy, but if you have any questions and want to get in touch directly I'd be more than happy to help where I can.
- Location
- Carmarthenshire, West Wales
I was told a vertical bore hole was a better system than horizontal pipework in trenches, can you comment or explain the difference? I am guessing a deep bore hole gets to a more reliable "core" ground temperature?
That's true, the variation in ground temperature will reduce as you go deeper, but for most practices it is considered fairly consistent below about 1m, hence why horizontal collectors are usually buried about 1.2m deep. Boreholes are mostly used where space is constrained. Generally, any benefits from the more consistent ground temperature will not outweigh the increased costs of installing boreholes.
- Location
- America's dairyland
A bore hole is used where you can't or don't want to tear up the ground. The variation in ground temp is NOT the issue, in fact a deeper loop without heat added in the summer time will cool over several years. Geothermal heat is a very small part of the heat absorbed from the ground, most of it is the average annual temp, that is, absorbed during the warmer seasons, and that is replenished faster at shallower depths than deeper depths. A borehole will generally have enough ground water movement that the depth is not a drawback, but the size will usually be scrimped compared to a flat shallow loop, because of the high cost.
Geo Tom, how common are air to air, or warm air heating air sourced heat pumps? They are very common in parts of the US and work well in those areas. We have enough old houses with hot water heat, it's almost unheard of to try to make that work with ground source, much less air source hot water heat pump.
Geo Tom, how common are air to air, or warm air heating air sourced heat pumps? They are very common in parts of the US and work well in those areas. We have enough old houses with hot water heat, it's almost unheard of to try to make that work with ground source, much less air source hot water heat pump.
Are you happy with the heat recovery system? Multiple pipes to it?
In housing, air to air heat pumps are less common in the UK than the US, as far as I am aware. But we do find them in commercial buildings, where forced ventilation is needed such as in some air handling units. We tend to use AC units a lot less than your side of the pond and I wonder if that has resulted in their increased popularity in the states with reversible units installed.
SilliamWhale
Member
Like what?
If you are not in a rush, wit for technology to catch up fora solution. Thermal battery is one way to resolve, and MOD are developing with an SME Supplier one that looks really promising - Cylo. Cheaper than gas, links to existing wet system, runs off cheap rate mains and/or PV. Should be ready for market in 2023.
Link??
nowt on google
Couldn't see owt...
ollie989898
Member
HVO is drop in replacement for diesel, it's not beyond the genius of man to produce a kerosene replacement.
SilliamWhale
Member
Could we produce enough of that?