It is currently 28 Mar 2024, 19:52

Insulate Britain

Hang up your Chisels and Plane blades and take a load off with a recently turned goblet of your favourite poison, in the lounge of our Gentlemen's (and ladies) Club.

Re: Insulate Britain

Postby RogerS » 20 Oct 2021, 09:48

My understanding is that you put the thick concrete blocks or similar on the inside face and insulation on the external. I suspect most of your heat gain is radiant heat through the windows.

But MikeG is our professional in this area.
If opportunity doesn't knock, build a door.
User avatar
RogerS
Petrified Pine
 
Posts: 13291
Joined: 21 Jul 2014, 21:07
Location: Nearly finished. OK OK...call me Pinocchio.
Name:

Re: Insulate Britain

Postby Mike G » 20 Oct 2021, 10:17

RogerS wrote:I love this sentence

Windows for a semi-detached house that are A-rated, taking in as much heat as they let out, would cost about £4,250, with energy bill savings of about £75 per year.

Confirming what we've known all along that the cost-benefit case for double-glazing is pretty dire.


That cost benefit analysis is only right if you are taking out perfectly good windows and replacing them. Windows need replacing periodically anyway, whether that is every 20 or 200 years. When you replace them, you are required to replace them with double glazing. So, the over-cost for using the best performing glazing is only then a few hundred pounds, meaning a payback period of only a year or three.
Last edited by Mike G on 20 Oct 2021, 12:50, edited 1 time in total.
User avatar
Mike G
Sequoia
 
Posts: 9834
Joined: 30 Jul 2014, 22:36
Location: Suffolk
Name:

Re: Insulate Britain

Postby Lurker » 20 Oct 2021, 10:19

Ignoring the financial costs of heat pumps, how long is their carbon footprint payback?
Lurker
Old Oak
 
Posts: 2447
Joined: 26 Nov 2020, 10:15
Location: Loughborough
Name:

Re: Insulate Britain

Postby Just4fun » 20 Oct 2021, 10:23

RogerS wrote:The other thing that they've skated over is that, with a heat pump, you will need to put in either underfloor heating or replace all your radiators with much larger ones! They leave the cost of that out of the figures !

Maybe, maybe not. It depends on the existing system. When we replaced our oil burner with a GSHP we didn't need to change radiators or anything else, we just put in the heat pump.
Just4fun
New Shoots
 
Posts: 221
Joined: 26 Nov 2020, 11:07
Location: Finland
Name:

Re: Insulate Britain

Postby RogerS » 20 Oct 2021, 10:26

Just4fun wrote:
RogerS wrote:The other thing that they've skated over is that, with a heat pump, you will need to put in either underfloor heating or replace all your radiators with much larger ones! They leave the cost of that out of the figures !

Maybe, maybe not. It depends on the existing system. When we replaced our oil burner with a GSHP we didn't need to change radiators or anything else, we just put in the heat pump.


I'm simply quoting these people

https://www.cse.org.uk/advice/renewable ... -heat-pump
If opportunity doesn't knock, build a door.
User avatar
RogerS
Petrified Pine
 
Posts: 13291
Joined: 21 Jul 2014, 21:07
Location: Nearly finished. OK OK...call me Pinocchio.
Name:

Re: Insulate Britain

Postby Lurker » 20 Oct 2021, 10:27

Just4fun wrote:
RogerS wrote:The other thing that they've skated over is that, with a heat pump, you will need to put in either underfloor heating or replace all your radiators with much larger ones! They leave the cost of that out of the figures !

Maybe, maybe not. It depends on the existing system. When we replaced our oil burner with a GSHP we didn't need to change radiators or anything else, we just put in the heat pump.


I may be wrong, but hasn’t Finland got a very efficient hydroelectric scheme making your electricity both cheap and reliable
Lurker
Old Oak
 
Posts: 2447
Joined: 26 Nov 2020, 10:15
Location: Loughborough
Name:

Re: Insulate Britain

Postby AJB Temple » 20 Oct 2021, 12:46

It's an interesting consideration. We do not have access to mains gas. Our heating is oil and we already have a year's supply in stock. However, the oil boiler is old and inefficient. We've been putting off changing it partly because I would like to explore alternatives. The problem is the old parts of the house are thermally inefficient, and underfloor heating or a warn air ventilation system are not viable. We are stuck with radiators, almost all of which I have replaced.

Air source heat pumps I find unconvincing, especially as we have no solar to deal with the electrical energy inputs. Am still thinking about a pellet burner system.

The economic case for any upgrade is not just about payback period for me. Of just as much importance is what effect will any change (or absence of change) have on property value? It's unlikely that we will stay here for more than, say, 10 years. With energy costs rising rapidly, houses that have modern, efficient systems are likely to command a better price and be easier to sell.
Don't like: wood, engines, electrickery, decorating, tiling, laying stone, plumbing, gardening or any kind of DIY. Not wild about spiders either.
User avatar
AJB Temple
Sequoia
 
Posts: 5431
Joined: 15 Apr 2019, 09:04
Name:

Re: Insulate Britain

Postby RogerS » 20 Oct 2021, 13:00

Far as ground source heat pumps are concerned most people think about a large footprint of pipes horizontal.

At our last place, the guy across the road produced a really good spreadsheet (sadly I have lost my copy) that looked at the CBA for virtually every conceivable alternative. In the end he settled for a vertical borehole.
If opportunity doesn't knock, build a door.
User avatar
RogerS
Petrified Pine
 
Posts: 13291
Joined: 21 Jul 2014, 21:07
Location: Nearly finished. OK OK...call me Pinocchio.
Name:

Re: Insulate Britain

Postby Just4fun » 20 Oct 2021, 13:46

Lurker wrote:I may be wrong, but hasn’t Finland got a very efficient hydroelectric scheme making your electricity both cheap and reliable

I wish that were true.
This website says electricity prices in Finland are slightly higher than in the UK. I'm not sure I believe that, but I doubt there is much in it either way.
Power generation seems very reliable here but power distribution is less reliable. We live in a land of forests and used to get regular outages as trees came down on the lines. A few years ago they changed to buried lines around us and said this would be more reliable. I can't say I have noticed any improvement but I don't have any stats to know for sure.
Just4fun
New Shoots
 
Posts: 221
Joined: 26 Nov 2020, 11:07
Location: Finland
Name:

Re: Insulate Britain

Postby Just4fun » 20 Oct 2021, 13:52

RogerS wrote:Far as ground source heat pumps are concerned most people think about a large footprint of pipes horizontal.

At our last place, the guy across the road produced a really good spreadsheet (sadly I have lost my copy) that looked at the CBA for virtually every conceivable alternative. In the end he settled for a vertical borehole.

The best solution can be different for different locations. When we had ours installed the supplier considered bore holes but being on solid rock that was rejected. They also considered putting a pipe in the lake but that is 130m from the house and vertically significantly lower so horizontal pipes running out into our field at the back were our best choice. You have to look on a case-by-case basis I think.
Just4fun
New Shoots
 
Posts: 221
Joined: 26 Nov 2020, 11:07
Location: Finland
Name:

Re: Insulate Britain

Postby Just4fun » 20 Oct 2021, 14:05

AJB Temple wrote:Am still thinking about a pellet burner system.

We seriously considered pellets before opting for a GSHP. There were 3 main reasons why we didn't go for pellets:

    At the time they were quite new & novel around here and it was not at all clear how the price & availability of pellets would develop. I have no idea how this worked out so we may have been right or wrong to have doubts.
    You need a lot of space to store pellets because they are not energy-dense. Plus we would have needed to have a lorry load delivered at a time for the delivery costs to be viable. The storage implications put us off.
    How reliable will the feed mechanism be after a few years getting bunged up with dust from the pellets? We thought the GSHP would probably require less maintenance & attention.

Had there been domestic scale machinery available (at a sensible price) for us to produce our own pellets from trees on our own land we would have been more interested. In retrospect, being terminally lazy I am glad that option was not open to us.
Just4fun
New Shoots
 
Posts: 221
Joined: 26 Nov 2020, 11:07
Location: Finland
Name:

Re: Insulate Britain

Postby RogerM » 20 Oct 2021, 14:09

It sounds like a lot of us are going through the same thought process. I live in a 1970's "box" which has some polystyrene sheet cavity wall insulation, and 250mm of fibreglass mat in the loft. Apart from our kitchen extension, there is no insulation in the solid floors, so UFH is not an option.

My reading up on air source heat pumps leads me to conclude that they can be noisy, and if the outside air temperature drops to 5C or below, they become increasingly less effective and use exponentially more power. Then there is the need to site them outside where they are open to the elements, as well as thieves who will be looking for something else to nick as catalytic converters become less common with the advent of electric cars. The wear and tear from the elements is much greater in coastal locations due to the salt content in the air. Although we are 1/2 mile from the sea, our windowns get covered in salt after a south-westerly storm.

Ground source heat pumps are more costly to install, but are sited inside the house so do not suffer from the elements or risk of theft. They are smaller, and considerably quieter, than their air-source brethren - no more than an average dishwasher. We have 1/2 acre of garden, including a large lawn which would probably be large enough for a shallow "slinky" array. However, I have read that a deep borehole will be much more efficient as the temperature of the ground 100m below the surface is remarkably stable at around 12C even through the hardest winter. A bore hole does add about £8k to the installation cost though, although it doesn't mean trashing your garden in the same way as a shallow array does. I suspect that there will be a law of diminishing returns here though, and suspect that in the southwest, the extra efficiency of a bore hole over a shallow "slinky" array would be marginal.

With a 10 year old Worcester-Bosch oil-fired condensing boiler, our maintenance engineer reckons it should last at least another 10 years with regular servicing. His firm also does Heat Pump installations, and when i told him we were in no hurry to convert, his reply was "Very wise. Hang on to this one as long as you can".
User avatar
RogerM
Nordic Pine
 
Posts: 811
Joined: 21 Jul 2014, 21:47
Location: South Devon
Name: Roger

Re: Insulate Britain

Postby Andyp » 20 Oct 2021, 15:13

We have a large enough garden for a GSHP and we are on clay, but not sure how deep.

How wide does a vertical bore hole need to be?

With water and plenty of plastic tube it is possible to bore a hole without drilling, unless you hit rock of course



And for Malc and other non flash users.

https://m.youtube.com/watch?v=1Ue2DkG64r8
I do not think therefore I do not am.

cheers
Andy
User avatar
Andyp
Petrified Pine
 
Posts: 11718
Joined: 22 Jul 2014, 07:05
Location: 14860 Normandy, France
Name: Andy

Re: Insulate Britain

Postby RogerM » 20 Oct 2021, 15:58

Andyp wrote:How wide does a vertical bore hole need to be?


From what I was reading Andy, about 6" or 150mm. They go down 60m - 200m, depending on the installation.
User avatar
RogerM
Nordic Pine
 
Posts: 811
Joined: 21 Jul 2014, 21:47
Location: South Devon
Name: Roger

Re: Insulate Britain

Postby Andyp » 20 Oct 2021, 16:44

I think on the vid he was using what looks like 40mm pipe and went down 40 metres. I'll not be trying it any time soon.

We don't have a boiler to replace anyway. Everything electric, convector heaters in every room. Only used in upstairs bathroom and kitchen. Rest of house heated from wood burner in the winter. Only gas we use is bottled for the hob. Two 13kg bottles a year. Water heated in what is effectively a 200l immersion heater on cheaper overnight tariff.
The large south facing room would be ideal for south facing solar capture of some sort either water heating or lecky panels. We wont be here long enough for payback.

We have to keep a close on the weather forecast before I light the wood burner. If the sun is out and the fire is alight we can reach high 20s in the living room easily during the day.
I do not think therefore I do not am.

cheers
Andy
User avatar
Andyp
Petrified Pine
 
Posts: 11718
Joined: 22 Jul 2014, 07:05
Location: 14860 Normandy, France
Name: Andy

Re: Insulate Britain

Postby RogerM » 20 Oct 2021, 17:11

Andyp wrote:I think on the vid he was using what looks like 40mm pipe and went down 40 metres. I'll not be trying it any time soon.


Andy - I was taking my info from this site https://www.kensaheatpumps.com/boreholes/ which seems to know what it's talking about, and for us it is local too. I guess you could easily thread a 40mm flow and return down a 150mm bore hole.
User avatar
RogerM
Nordic Pine
 
Posts: 811
Joined: 21 Jul 2014, 21:47
Location: South Devon
Name: Roger

Re: Insulate Britain

Postby jimmy s » 20 Oct 2021, 23:10

The vertical borehole depths are worked out on a site by site basis depending on the heat requirements/ thermal conductivity of the rock/ anticipated depth to rock etc. Normally about 6m centres. If there are a few being installed then ideally 8m centres or so.

We are just starting on a project with a GSHP with 9 boreholes so was on site today with the drillers. 150m deep boreholes with 40mm MDPE SDR11 ground probes into a collection manifold and will have 90mm flow and returns back to the heat pumps.

Cost here is about 10K a hole for the boreholes drilled, casings installed, and the holes grouted with bentonite.

Were on oil and I'm slowly working my way through the house insulating and installing UFH as I go. I'm hoping to just buy a heat pump myself and will probably just go with horizontal ground loops as we have enough land to go with this option.

Some of the air source heat pumps are ok and not as noisy. A few now are running on R290 (propane) which seems to be quite a good refrigerant looking at the COP figures.
jimmy s
New Shoots
 
Posts: 180
Joined: 06 Jan 2021, 19:55
Location: Dunfermline area
Name: Jimmy Simpson

Re: Insulate Britain

Postby jimmy s » 20 Oct 2021, 23:36

RogerM wrote:It sounds like a lot of us are going through the same thought process. I live in a 1970's "box" which has some polystyrene sheet cavity wall insulation, and 250mm of fibreglass mat in the loft. Apart from our kitchen extension, there is no insulation in the solid floors, so UFH is not an option.

My reading up on air source heat pumps leads me to conclude that they can be noisy, and if the outside air temperature drops to 5C or below, they become increasingly less effective and use exponentially more power. Then there is the need to site them outside where they are open to the elements, as well as thieves who will be looking for something else to nick as catalytic converters become less common with the advent of electric cars. The wear and tear from the elements is much greater in coastal locations due to the salt content in the air. Although we are 1/2 mile from the sea, our windowns get covered in salt after a south-westerly storm.

Ground source heat pumps are more costly to install, but are sited inside the house so do not suffer from the elements or risk of theft. They are smaller, and considerably quieter, than their air-source brethren - no more than an average dishwasher. We have 1/2 acre of garden, including a large lawn which would probably be large enough for a shallow "slinky" array. However, I have read that a deep borehole will be much more efficient as the temperature of the ground 100m below the surface is remarkably stable at around 12C even through the hardest winter. A bore hole does add about £8k to the installation cost though, although it doesn't mean trashing your garden in the same way as a shallow array does. I suspect that there will be a law of diminishing returns here though, and suspect that in the southwest, the extra efficiency of a bore hole over a shallow "slinky" array would be marginal.

With a 10 year old Worcester-Bosch oil-fired condensing boiler, our maintenance engineer reckons it should last at least another 10 years with regular servicing. His firm also does Heat Pump installations, and when i told him we were in no hurry to convert, his reply was "Very wise. Hang on to this one as long as you can".



You really need to insulate as much as possible first as the cost of heat pumps per KW is quite high. Also it can be tricky to get UFH to work well with high heat losses. You may find that the floor finishes limit the heat outputs from the floors as for example most natural timbers are only suitable for a surface temp of 27 deg C this works out at about 70 watts per sqm output which is often not enough if insulation values are poor. Amtico and Karndean flooring are also about 27 but they go on glue line temp rather than surface temp. Other floor finishes are normally good up to 29 deg C or 90 watts per sqm which is the max permitted surface temp in normally occupied areas. You can get more by using peripheral zones etc and can go higher in wet rooms etc. Warm air heating and high heat losses is going to be difficult.

You can also tie radiators into the UFH loops which sometimes helps.

The main thing that affects heat pumps is the pressure differential over which the compressor has to operate as that's what governs the electrical input. The higher the ground or air temp then the higher the evaporator temp can be in the heat pump as it must run several degrees C below the temp of the heat source to enable heat transfer. The temp the heating runs at pretty much governs the discharge pressure from the compressor as well.

You have to be careful with slinkys. They can have issues with overcooling the ground if not done properly. Horizontal ground loops are really more of a large scale solar absorber than geothermal. If you extract heat from too small an area the ground can freeze. Ice is a very good insulator and it can take an age to thaw out.

If thinking about air source in costal areas then the evaporator on the heat pump really wants a epoxy finish such as blygold to stop the aluminium fins corroding. The COP starts dropping as they get to zero deg C as the fins on the evaporator starts to ice up and normally they have to go into a reverse cycle defrost.
jimmy s
New Shoots
 
Posts: 180
Joined: 06 Jan 2021, 19:55
Location: Dunfermline area
Name: Jimmy Simpson

Re: Insulate Britain

Postby AJB Temple » 21 Oct 2021, 00:43

:text-goodpost:
Don't like: wood, engines, electrickery, decorating, tiling, laying stone, plumbing, gardening or any kind of DIY. Not wild about spiders either.
User avatar
AJB Temple
Sequoia
 
Posts: 5431
Joined: 15 Apr 2019, 09:04
Name:

Previous

Return to The Woodmangler's Retreat

Who is online

Users browsing this forum: No registered users and 18 guests