# Heat pump for older homes



## Clonback (15 Feb 2022)

I see there are air source heat pumps which combine heat pump with a gas boiler module.They claim the heat pump will provide over 90% of the heat with the boiler module providing the rest.This would suit my property as there would be no need to dig up/insulate floors and less disruption. Any feedback greatly appreciated


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## Micks'r (15 Feb 2022)

I'm not particular familiar with any specific systems on the market but high temperature heating systems (oil & gas fired) have been mimicking low temperature systems (heat pump) for decades and therefore it should be no issue to combine them once the logic/control system is properly thought through.
However the best approach, in my opinion, is to where feasible reduce the need for the heat in the first place by finding & addressing the low hanging heat loss fruit.


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## Clonback (15 Feb 2022)

Micks'r said:


> I'm not particular familiar with any specific systems on the market but high temperature heating systems (oil & gas fired) have been mimicking low temperature systems (heat pump) for decades and therefore it should be no issue to combine them once the logic/control system is properly thought through.
> However the best approach, in my opinion, is to where feasible reduce the need for the heat in the first place by finding & addressing the low hanging heat loss fruit.


RVR Energy Technology in Kenmare provide a product called Magis Combo which appears to suit older homes.


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## Micks'r (15 Feb 2022)

I would like to see more detail on their claim that the heatpump will supply 90% of the heating to a typical house.
I don't really see the point of the extra expense and use of resources.
So why not just have a good gas boiler and forget about the heat pump?
Is that system not akin to having 2 cars sitting in the drive;  an EV for the short journeys and a diesel car for the longer journeys when the diesel car would cover both journey types?


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## Clonback (16 Feb 2022)

I have arranged for site visit by RVR technology and will revert with outcome.

It would appear that their system is more akin to a hybrid car than having 2 cars but let me get the facts.


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## Micks'r (16 Feb 2022)

Clonback said:


> I have arranged for site visit by RVR technology and will revert with outcome.
> 
> It would appear that their system is more akin to a hybrid car than having 2 cars but let me get the facts.


Will you enquire on the detail behind their claim that more than 90% of the heating required comes from the hp.

That's a great analogy with the hybrid car. My (limited) understanding of hybrid cars is that they are very efficient if you do small mileage daily, say 50 to 60 km's but are not efficient at all when higher daily mileage is normally needed. So, if you need to do a lot of km's (aka have a high heat loss house in this analogy) then a hybrid might not be the best choice!


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## bstop (16 Feb 2022)

The problems with a hybrid car are that you get the advantages and disadvantages of batteries and combustion engine. The disadvantages are that you still need the expensive oil changes and servicing of the combustion engine and the weight and eventual cost of replacing the battery. Also the extra cost of purchase and the complicated electronics and components which control the two drive systems.
Having a gas boiler and heat pump arrangement with electronics to combine their operation will result in a very expensive system which will need boiler servicing and separate heat pump servicing. When a fault develops on the system you may need the services of a boiler service engineer, a heat pump engineer and an expert on the electronic controls.


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## fayf (17 Feb 2022)

Agree with many of the thoughts here @bstop, i looked at hybrid v fully
electric  cars last year, and concluded after a lot of reading and test drives, pricing, overall annual running costs, and driving experience etc, EV was the way to go. 
Took the EV plunge, and have never looked back.

Similarly, i have been looking into heat pumps + replacing a 27 year old double glazed windows in recent months. We also currently have a 27 year old gas boiler. 

Have had a few quotes, and late last year i was saying NO to a heat pump, as it did not seem to make financial sense, the heat pumps were in the 10 to 12k price bracket alone, this included replacements for a quarter of our existing radiators, as not all are suitable to work with heat pumps.  So with the excessive cost, even after grants, i diverted course, onto looking at a new efficient condenser boiler and a full window/door replacement.

However the recently revised, and much increased grants, have changed all that, so i need to look over it all again. 

What i did learn along the way about Heat Pumps, is they will only work efficiently, if your house is well insulated, as others have mentioned, get the low hanging fruit sorted out first, so that means getting attic insulation & walls pumped - we already have those two done, recently, any open chimneys ? we boxed that off with a stove replacing fireplace, and has already made a noticeable difference. Next, is windows & doors, which contribute significantly to heat loss. One of the window/door quotes has triple glazing with a uv value of 1, or double glazing with a little higher u value 1.4, I am leaning towards triple glazed as my understanding is, the lower u values will make the heat pump work more efficiently, and its also an opportunity to get better external noise reduction, with triple glazed. Apparently there is some solar gain loss, with triple glazed, as they apparently leave less sun heat into the house, i’m fine with that, as house can often, be too hot in summer months, as it is.

Also, i learned that heat pumps heat a house very slowly, so typically, are most efficient, when left run continuously, they will increase temperature as required, to a chosen temperture setting, then come on/off, to keep it at that temperture. 
Water can be heated, independantly.

Do some reading up on it, there is a lot to take in, and its new’ish and different tech, and involves changing, how one does things. The more you research, the more you will understand it better, and be in a position to make a more informative choice, and minimise any “surprises”!


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## Baby boomer (17 Feb 2022)

Agree entirely, inespecially with heating and energy on an upward price trajectory.  We did a heatpump on new build In 2020 and it's fantastic.on comfort and price.  Looking at solar next.


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## fayf (17 Feb 2022)

I put in Swiss made, AMK Solac solar tubes in 2010, they were of the more expensive tubes around, when i queried it, i was told the yield is amongst the highest on the market. Very impressive performance, and has been heating at least 80 % of our hot water ever since. After 12 years, i’l probably be taking them down, its possible to get them to work alongside a heat pump, but it looks too complex, and would have to get an upgraded tank with a solar coil, so will likely be loosing it.

I havent really looked into PV’s yet, so leave us know how you get on with that.


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## David_Dublin (17 Feb 2022)

I'm hearing lots of horror stories of heat pumps costing loads to run due to the unsuitability of them for the houses they're installed in.


fayf said:


> Agree with many of the thoughts here @bstop, i looked at hybrid v fully
> electric  cars last year, and concluded after a lot of reading and test drives, pricing, overall annual running costs, and driving experience etc, EV was the way to go.
> Took the EV plunge, and have never looked back.
> 
> ...


I think air tightness is number one in relation to heat loss, not insulation. The harder a heat pump has to work to maintain the required temperature the less economical it will be to run it. I've heard horror stories of heat pumps and how much they cost to run, usually due to not being right in the first place. My understanding is that it would take a lot of investment to make a heat pump work in an older house, where you have air leakage thru floors, doors, walls, ceilings etc. This is from reading anecdotal posts online as opposed to any great personal knowledge, education or experience.


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## fayf (17 Feb 2022)

Interesting. So, assuming attic is fully insulated to current standard, external walls are pumped, low 1 u value triple glazed windows and doors installed, what else is there, to improve air tightness in an older house ?


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## David_Dublin (17 Feb 2022)

Maybe an airtightness survey would tell you that? I'm not sure something being insulated necessarily means something being airtight. But maybe airtight was part of the detailing for your insulation. Certainly sounds like your windows and doors wont be an issue!


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## Micks'r (17 Feb 2022)

fayf said:


> Interesting. So, assuming attic is fully insulated to current standard, external walls are pumped, low 1 u value triple glazed windows and doors installed, what else is there, to improve air tightness in an older house ?


Tbh, until the house is tested you won't know but generally doors and windows can very often be the least of the issue. The main culprits are quite often the elemental junctions (for instance the junction between the floor and the wall) and cable / pipe penetrations of floor, roofs, walls including internal floors and walls.
This can be very difficult to "get" until you experience the test for yourself and see / feel what is going on. The level of air leakage can also vary quite a bit between different house types / eras and also depending on what "improvements" have been done over time. 
Adding / upgrading insulation in walls and attics rarely make any meaningful difference to a house with high air leakage because insulation addresses conductive heat loss whereas air tightening addresses convective losses (aka draughts). 
Relying on a heat pump to supply the heat at the required rate to match the losses in a building with high air leakage is very risky in the absense of addressing the primary heat loss mechanisms first.


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## Clonback (17 Feb 2022)

Micks'r said:


> Tbh, until the house is tested you won't know but generally doors and windows can very often be the least of the issue. The main culprits are quite often the elemental junctions (for instance the junction between the floor and the wall) and cable / pipe penetrations of floor, roofs, walls including internal floors and walls.
> This can be very difficult to "get" until you experience the test for yourself and see / feel what is going on. The level of air leakage can also vary quite a bit between different house types / eras and also depending on what "improvements" have been done over time.
> Adding / upgrading insulation in walls and attics rarely make any meaningful difference to a house with high air leakage because insulation addresses conductive heat loss whereas air tightening addresses convective losses (aka draughts).
> Relying on a heat pump to supply the heat at the required rate to match the losses in a building with high air leakage is very risky in the absense of addressing the primary heat loss mechanisms first.


Makes perfect sense.Do many people do an air leakage test?Should it be done before and after?


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## fidelcastro (19 Feb 2022)

Clonback said:


> Makes perfect sense.Do many people do an air leakage test?Should it be done before and after?


Before!. And ask Micks'r, he's an expert in this field.!


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## roker (20 Feb 2022)

Micks'r said:


> Tbh, until the house is tested you won't know but generally doors and windows can very often be the least of the issue. The main culprits are quite often the elemental junctions (for instance the junction between the floor and the wall) and cable / pipe penetrations of floor, roofs, walls including internal floors and walls.
> This can be very difficult to "get" until you experience the test for yourself and see / feel what is going on. The level of air leakage can also vary quite a bit between different house types / eras and also depending on what "improvements" have been done over time.
> Adding / upgrading insulation in walls and attics rarely make any meaningful difference to a house with high air leakage because insulation addresses conductive heat loss whereas air tightening addresses convective losses (aka draughts).
> Relying on a heat pump to supply the heat at the required rate to match the losses in a building with high air leakage is very risky in the absense of addressing the primary heat loss mechanisms first.


Would making the house airtight cause problems with condensation and black mold


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## Micks'r (20 Feb 2022)

roker said:


> Would making the house airtight cause problems with condensation and black mold


It absolutely can/will if not taken into account with an appropriate ventilation strategy or system. Air tightness needs to be balanced with ventilation otherwise issues will quickly arise and they can be severe.
When you consider that a typical family of 5 typically produce between 12 and 18 litres of water in the home per 24 hour period through normal activities of breathing, cooking, washing etc. This moisture is generally contained in the air and this "wet" air needs to be exchanged with "dry" external to maintain a dry house internally. When the house leaks a lot of air, i.e. is very draughty, this "wet" internal air is easily exchanged with the dry outside air. When the house is air tightened, appropriate ventilation will do this work when designed and used correctly.


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## roker (20 Feb 2022)

Micks'r said:


> It absolutely can/will if not taken into account with an appropriate ventilation strategy or system. Air tightness needs to be balanced with ventilation otherwise issues will quickly arise and they can be severe.
> When you consider that a typical family of 5 typically produce between 12 and 18 litres of water in the home per 24 hour period through normal activities of breathing, cooking, washing etc. This moisture is generally contained in the air and this "wet" air needs to be exchanged with "dry" external to maintain a dry house internally. When the house leaks a lot of air, i.e. is very draughty, this "wet" internal air is easily exchanged with the dry outside air. When the house is air tightened, appropriate ventilation will do this work when designed and used correctly.


If you are venterlating the house, you must have air in to replace it which will be cold air, so there is no such thing as a sealed house
The only alternative that I can think of is an extractor system that has a heat exchanger to heat the incoming air from the extracted air, this would control the house at positive pressure to prevent damp air entering the house


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## Alkers86 (21 Feb 2022)

After bringing our 1950s home up to A3 standard with a gas combi boiler, our annual gas bill is now in the region of €500 (110m2 terraced house).
It seems like madness to me to go and spend €10k-€12k on a heat pump to try and save a percentage of that €500 per annum. The payback period will be something like 20 years?


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## Clonback (21 Feb 2022)

Alkers86 said:


> After bringing our 1950s home up to A3 standard with a gas combi boiler, our annual gas bill is now in the region of €500 (110m2 terraced house).
> It seems like madness to me to go and spend €10k-€12k on a heat pump to try and save a percentage of that €500 per annum. The payback period will be something like 20 years?


You must be using nearly no gas when you subtract VAT,Carbon tax  and standing charges.The combi boiler makes great sense when your hot water needs are low.
In your case heat pumps would make no economic sense.The only issue going forward is carbon tax on fossil fuels is going one way  but you use so little it  makes no difference.


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## fayf (21 Feb 2022)

Alkers86 said:


> After bringing our 1950s home up to A3 standard with a gas combi boiler, our annual gas bill is now in the region of €500 (110m2 terraced house).
> It seems like madness to me to go and spend €10k-€12k on a heat pump to try and save a percentage of that €500 per annum. The payback period will be something like 20 years?


You have to do the maths alright, it definitely depends on circumstances, house type, current BER, running costs, payback & grants available. It does not make sense in many situations, but it does in others.

But there is also “comfort factor” which you can’t really monetise the value of that.

I have a 27 year old boiler, which will have to replaced soon, i checked a new condenser boiler but its about 4 k, & i won’t get any grants. Our windows are quite draughty, also 27 years old.

all new triple glazed windows (uv value of 1)and 2 new doors + heat pump, is coming in at roughly 24k, but grants are almost 15k, so it makes more sense for me.

Going the SEAI “One Stop Shop” route, my understanding, is  the following are the applicable grants for me:

Full Window Upgrade €4,000
Front & Back Door(800 each) €1,600
Heat Pump €6,500
Heating Controls  €700
Bonus to reach B2 Ber €2,000









						One Stop Shop Service
					

A complete home energy upgrade solution for homeowners. Find out more.




					www.seai.ie


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## Micks'r (21 Feb 2022)

roker said:


> If you are venterlating the house, you must have air in to replace it which will be cold air, so there is no such thing as a sealed house
> The only alternative that I can think of is an extractor system that has a heat exchanger to heat the incoming air from the extracted air, this would control the house at positive pressure to prevent damp air entering the house


There are several methods to adequately ventilate a house and the most appropriate one is often a function of house type, air tightness level & layout.
Tbh, I'm not sure what you are trying to say exactly but to clarify one point; external (cold) air coming into a house from outside during the heating season will always be dryer in absolute terms than the air leaving the house.


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## Alkers86 (22 Feb 2022)

fayf said:


> You have to do the maths alright, it definitely depends on circumstances, house type, current BER, running costs, payback & grants available. It does not make sense in many situations, but it does in others.
> 
> But there is also “comfort factor” which you can’t really monetise the value of that.
> 
> ...


I would be very concerned in that situatuon that you will end up with a very large electricity bill when the heat pump is installeed. What is your current BER? What sort of a house is it?


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## Browneyedgirl4 (22 Feb 2022)

Alkers86 said:


> After bringing our 1950s home up to A3 standard with a gas combi boiler, our annual gas bill is now in the region of €500 (110m2 terraced house).
> It seems like madness to me to go and spend €10k-€12k on a heat pump to try and save a percentage of that €500 per annum. The payback period will be something like 20 years?


Can I ask what measures you took to bring it up A3?


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## fayf (22 Feb 2022)

Its C3, a detached house, was D originally, but crept up after solar panels installed, walls pumped, and attic insulation in 2010, have since gotten additional insulation in the attic space, to bring it up to the upgraded insulation standard. My gas is relatively low because the solar tubes have been more productive than i ever thought they would be, its about €700 per annum


Alkers86 said:


> I would be very concerned in that situatuon that you will end up with a very large electricity bill when the heat pump is installeed. What is your current BER? What sort of a house is it?


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## Browneyedgirl4 (22 Feb 2022)

fayf said:


> Its C3, a detached house, was D originally, but crept up after solar panels installed, walls pumped, and attic insulation in 2010, have since gotten additional insulation in the attic space, to bring it up to the upgraded insulation standard. My gas is relatively low because the solar tubes have been more productive than i ever thought they would be, its about €700 per annum


how do the solar panels work....does it save electricity?


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## noproblem (22 Feb 2022)

As others who are more knowledgeable on all of this have said, this BER mullarkey is very iffy. Much better to know where you're losing heat in a house. We moved into our newly built house in 2005 and I've recently had all my windows and doors properly resealed, and in all cases the opening/closing hinges changed, front door had warped slightly with it's lock almost not working at all, changed lock completely and they "reset" the door, excellent now.  French doors had their hinges all changed and fully resealed with proper rubber sealer. The amount of draughts we had gotten used to, so took no notice of the heat that was going out, never mind wind/cold coming in. We hardly ever use the 2 open fireplaces, and have a special cap on both chimneys that is controlled from a chain that comes all the way down the chimney, we can open and close the chimney cap from there. I've only recently had one of the free surveys done with an SEAI man calling out. Nice man, checked my attic insulation, have already had my cavity pumped, and have a chat about how economical it might be for us to do a more thorough retro-fit. There was nothing in the grant for the work I had done with doors/windows. He told me it wouldn't  have had any effect on the BER rating in any case. In my simple mind, the methodology for the BER cert is very questionable. BUT, you need it for selling, for grants, etc, etc. I really do believe the powers that be should look at how efficient all those certs are, update them to include all the new, healthy, and very good ways one can have a really cosy house. Anyway, in the end, i'm pencilled in for an upgrade of the attic insulation, 200mm x 105 sq mtrs,  and also flooring 35 sq metres of the attic above the new insulation, they also give me a new BER cert when completed.  Total I will have to pay after grants, etc is €3500.00, this includes the BER Cert. It was just short of €5000.00 before grants taken out and it included a BER cert @ €300.00. I'm told it will be done inside the next 8 weeks aprox.
Could I have done all this myself a bit cheaper and forget about the grants? Yes, I'm fairly sure I could, but not by enough to make it worth it.
 Hope this info helps others.


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## Monbretia (22 Feb 2022)

This is all very interesting!  I have a very draughty house, wouldn't be too bad on the insulation front but it's the draughts getting in especially in dormer conversion and I'm convinced in through those recessed lights too.  On the plus side I have no mould/condensation problems  

I have a 30 yr old gas boiler, working fine thankfully but can't last forever, it's bulk tank so I have already been told all the pipes from the tank to the boiler will have to changed if I put in a new boiler, they are underground metal at the moment going under a patio too but not allowed apparently for any new work.   Thing is though I spend approx 1,200 per annum up to now (with prices rising who knows what it will be in future!) on gas which includes a hob, no clue on area of house in metres but it's approx 2500 sq ft inc attic conversion so I actually don't think that is too expensive, hard to know what amount of that I would save on an upgrade.

Windows are obviously 30 yrs old but I don't fell any draughts in around them and they seem still pretty good, I did have them serviced in case they needed new seals or anything but other than a few broken locks they were fine.

Not sure what I would tackle first to try and make the house heat pump ready if/when necessary, not sure it would be the best option at all, even if I could solve the draught issues I'd have to change all the radiators too I presume which doesn't appeal to me either as they take up enough wall space already plus my radiator cabinets wouldn't fit!   I'm not going to dig up the floors for underfloor and end up having to replace flooring.


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## fayf (22 Feb 2022)

Browneyedgirl4 said:


> how do the solar panels work....does it save electricity?


My solar panels heat water only, i’d guess at least 80 % of our annual hot water requirement, comes from them, its the main reason, my annual gas bill is relatively low. 

Solar PV (Photo Voltaic) are a different type of solar panel, but they generate electricity, but i don’t have those, others may know more about them.


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## fayf (22 Feb 2022)

“issues I'd have to change all the radiators too I presume which doesn't appeal to me either”

@Monbretia :

A recent quote i got for a heat pump, says most of the 13 existing rads are fine, we have to replace 5 of them, 3 of those are bathroom towel heaters.So it is not nexessarily the case, that there is a high proportion of the cost going on new rads.

Ideally, ground floor insulation would help, but i won’t be doing that, its too big a job, too expensive, and very disruptive.


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## Leo (23 Feb 2022)

fayf said:


> Solar PV (Photo Voltaic) are a different type of solar panel, but they generate electricity, but i don’t have those, others may know more about them.


This is well covered in other threads.


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## Leo (23 Feb 2022)

noproblem said:


> There was nothing in the grant for the work I had done with doors/windows. He told me it wouldn't have had any effect on the BER rating in any case. In my simple mind, the methodology for the BER cert is very questionable. BUT, you need it for selling, for grants, etc, etc. I really do believe the powers that be should look at how efficient all those certs are, update them to include all the new, healthy, and very good ways one can have a really cosy house.


There definitely are limitations to the current BER process, assessors basically enter known or estimated values for all the relevant components of the home, U values for windows for instance. The software then calculates the final rating. 

What it can't do is measure how well all those components have been installed or maintained over the years. To implement a comprehensive test that would to all you say would mean a test that costs in the thousands. Warts and all, the current test that you can get done for less than €200 makes more sense. More education is likely a good compromise to addressing the shortcomings of the test.


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## Alkers86 (23 Feb 2022)

Browneyedgirl4 said:


> Can I ask what measures you took to bring it up A3?


Detailed here: https://www.askaboutmoney.com/threads/estimate-renovation.226008/post-1761307


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## Hooverfish (24 Feb 2022)

You can do your own room by room heat loss survey at www.heat-engineer.com for the massive sum of £12. Very good software, and an inexpensive way to find out the stuff you need to know. Cross reference the results against your actual energy bills. The best source of information I've found so far is the facebook group Heat Pumps UK and Ireland which has a number of experienced installers who give advice. It's quite a lot better than the similar Irish only group. https://www.facebook.com/groups/1432303803563678


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## Leo (25 Feb 2022)

Hooverfish said:


> You can do your own room by room heat loss survey at www.heat-engineer.com for the massive sum of £12.


Are you able to go into U-Value details for the various components and does it account for ventilation or heat loss from air leakage?

I suspect it's similar to the calculators that are widely available for free online such as this or this, but would be interested if it offered more. For instance, the free ones don't tend to consider solar gains.


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