ᐅ Underfloor Heating in Older Buildings: Retrofitting Options
Created on: 2 Jan 2022 16:49
L
littlebirdL
littlebird2 Jan 2022 16:49Hello,
since we are still looking for an apartment or a house, I would like to gather general information about retrofitting underfloor heating.
1. Is it even practical to install underfloor heating afterwards if there is an existing gas heating system with radiators? If there is a garden, does it make sense to install an air source heat pump, especially in older buildings that are generally not very well insulated? Is a gas heating system suitable for use with an air source heat pump?
2. Since older buildings usually have low ceiling heights, I am concerned whether insulation on the floor plus underfloor heating will take up too much space and cause issues with door height. What options are there for the doors? Do they simply need to be smaller?
3. Can the manifold for the underfloor heating be installed in the basement, or would that cause the pipe runs inside the house to be too long?
4. Since this is a retrofit, how complicated is it to build a vertical shaft for the underfloor heating, for example spanning three floors (ground floor, first floor, and second floor)? Is it allowed to use the chimney for this purpose?
Thank you!
since we are still looking for an apartment or a house, I would like to gather general information about retrofitting underfloor heating.
1. Is it even practical to install underfloor heating afterwards if there is an existing gas heating system with radiators? If there is a garden, does it make sense to install an air source heat pump, especially in older buildings that are generally not very well insulated? Is a gas heating system suitable for use with an air source heat pump?
2. Since older buildings usually have low ceiling heights, I am concerned whether insulation on the floor plus underfloor heating will take up too much space and cause issues with door height. What options are there for the doors? Do they simply need to be smaller?
3. Can the manifold for the underfloor heating be installed in the basement, or would that cause the pipe runs inside the house to be too long?
4. Since this is a retrofit, how complicated is it to build a vertical shaft for the underfloor heating, for example spanning three floors (ground floor, first floor, and second floor)? Is it allowed to use the chimney for this purpose?
Thank you!
N
Nice-Nofret2 Jan 2022 16:581. It depends
2. Trimming doors... suitable for Appenzeller and others that are too short
3. Yes, it can be installed in the boiler room
4. It depends
2. Trimming doors... suitable for Appenzeller and others that are too short
3. Yes, it can be installed in the boiler room
4. It depends
D
Deliverer2 Jan 2022 17:341: Yes. Possibly supplemented by ceiling heating and wall heating where appropriate. If you do it, do it properly from the start, since underfloor heating is only subsidized when combined with a heat pump conversion. If it’s not a high mountain area, an air-to-water heat pump is quite sensible. Refrigerant R290. Additional insulation is also recommended. Definitely the roof and basement. Exterior walls and windows depend heavily on the existing structure and how important it is. Engineering firms or (good) energy consultants can calculate that.
And yes, retrofitting underfloor heating is worthwhile: In an uninsulated older building (on average from the 1970s), I achieved a very heat-pump-friendly 36°C (97°F) supply temperature at an outside temperature of -10°C (14°F).
2: There are systems with lower build-up heights – but they cost a bit more. I installed one just last year for that exact reason (more details available by PM). Sometimes it can also be structurally advantageous to have 5cm (2 inches) instead of 8cm (3 inches) screed. Depending on the situation, you do not need insulation underneath. You can also insulate the basement from below. Between the ground floor and upper floor it doesn’t really matter, since the heat will at worst flow downward. And yes, doors can be shortened.
3: Usually, the pipes run directly from the boiler room straight up to the top, where a manifold for each floor branches off. Distribution to individual rooms then runs in the screed, parallel to the heating loops. It’s common to use a hallway that everything runs through. That space might not even need its own loop, which typically would be too small anyway.
4: Replace old riser pipes (radiators were also connected from bottom to top in the old system), the old chimney might be usable as well. By the way, the cables for the photovoltaic system often run through here, as well as the pipes for the ventilation system ;-). The old radiator recesses beneath windows sometimes offer flexibility too, either for riser pipes or for the heating manifolds.
Good luck!
And yes, retrofitting underfloor heating is worthwhile: In an uninsulated older building (on average from the 1970s), I achieved a very heat-pump-friendly 36°C (97°F) supply temperature at an outside temperature of -10°C (14°F).
2: There are systems with lower build-up heights – but they cost a bit more. I installed one just last year for that exact reason (more details available by PM). Sometimes it can also be structurally advantageous to have 5cm (2 inches) instead of 8cm (3 inches) screed. Depending on the situation, you do not need insulation underneath. You can also insulate the basement from below. Between the ground floor and upper floor it doesn’t really matter, since the heat will at worst flow downward. And yes, doors can be shortened.
3: Usually, the pipes run directly from the boiler room straight up to the top, where a manifold for each floor branches off. Distribution to individual rooms then runs in the screed, parallel to the heating loops. It’s common to use a hallway that everything runs through. That space might not even need its own loop, which typically would be too small anyway.
4: Replace old riser pipes (radiators were also connected from bottom to top in the old system), the old chimney might be usable as well. By the way, the cables for the photovoltaic system often run through here, as well as the pipes for the ventilation system ;-). The old radiator recesses beneath windows sometimes offer flexibility too, either for riser pipes or for the heating manifolds.
Good luck!
littlebird schrieb:
Since we are still looking for an apartment or a house, I want to generally learn about the retrofitting of underfloor heating. You are putting the cart before the horse here. Apart from the fact that you can only really discuss how to best proceed once you have specific properties in mind: are you seriously planning to choose a property based on how easily underfloor heating can be retrofitted there?
littlebird schrieb:
especially in older buildings, which generally are not well insulated … this issue will be mitigated by mandatory legal retrofit requirements.
littlebird schrieb:
a vertical shaft [...] Is it permitted to use the chimney for this purpose? Your expectations reflect a level of naivety that advises against personal involvement in technical planning processes.
https://www.instagram.com/11antgmxde/
https://www.linkedin.com/company/bauen-jetzt/
D
Deliverer2 Jan 2022 18:53Oh come on @11ant, I was also more naive and less knowledgeable before starting renovations and new builds. You have to start somewhere. The fact that the original poster is even considering these things shows foresight.
And yes, I would definitely choose a house based on whether it has underfloor heating or if it can be retrofitted. In the long run, every house will be heated with a heat pump, and the "area" factor is extremely important for ongoing costs. Besides, it's a comfort benefit that, in my opinion, is priceless.
And yes, I would definitely choose a house based on whether it has underfloor heating or if it can be retrofitted. In the long run, every house will be heated with a heat pump, and the "area" factor is extremely important for ongoing costs. Besides, it's a comfort benefit that, in my opinion, is priceless.
Deliverer schrieb:
Come on @11ant, I was also more naive and less knowledgeable before my new build and renovation. You have to start somewhere. And the fact that the original poster is even thinking about it shows foresight. Foresight is better than ignorance, I agree with that, but that’s where it ends: countless threads here show people driven nearly to madness by stories claiming that a homeowner must be comprehensively informed about everything. I know plenty of people living in what would today be seen as surprisingly low-tech houses from fifty years ago, who are healthy and well into their eighties without ever having compared boiler data sheets.
Deliverer schrieb:
And yes, I would definitely choose a house based on whether it has underfloor heating or if it can be retrofitted. From experience, second-hand properties risk compromises in more than just a dozen different areas—but to make precisely this detail the “master question” would probably have been called a “risk” by Thööölke ;-)
https://www.instagram.com/11antgmxde/
https://www.linkedin.com/company/bauen-jetzt/
Similar topics