Hello dear forum members,
I have been quietly reading along from time to time, but now I feel compelled to ask a question myself (bravely).
We don’t yet have a plot of land or a house but are very interested. Everywhere you look and listen, there are contradictory statements depending on who is trying to sell what. It’s clear there is no one perfect heating system; each has its advantages and disadvantages, but it is all really confusing. Therefore, I am interested in your experiences, please also the positive ones!
Our plot will be about 1000m2 (0.25 acres), currently we have one in sight. The house should be about 160 to 180m2 (1700 to 1900 square feet). Which energy efficiency standard (KfW level) is still unclear. Location: southern Lower Saxony, a bit of a low mountain region, not a water protection area.
Unfortunately, there is no natural gas supply there, otherwise we would have chosen a condensing boiler.
I find a liquefied petroleum gas (LPG) tank in the garden unattractive – and I don’t know if it’s possible to have it underground, but I don’t like the idea of “refueling” either; I didn’t like that when we had an oil heating system before either...
Right now, the ground source heat exchanger with deep geothermal drilling is the most interesting option for us.
I’ve already done some research on soil conditions (talked to geologists):
- Limestone, clay, gypsum, no anhydrite; little water exchange, so a groundwater heat pump is probably out of the question, deep drilling should be possible but not easy. The deeper, the better.
The couple next door just built, and because of the water situation, they decided against a basement. A pity but not a big deal.
Wish:
-> The bathroom should be able to reach 24°C (75°F) – I’m really sensitive to cold!! Freezing in winter is truly a no-go for me – just how I am...
Now to a summary of the information I have gathered so far – it is very confusing for us:
Geothermal:
- 40 to 100m (130 to 330 feet) drilling depth, the deeper the better, but of course more expensive
- good efficiency, provided everything works out
- no clear information on durability, problems with earth movements causing pump failure; a representative from a prefab house company said they no longer offer geothermal systems because of many returns and dissatisfied customers, given the high costs!
- if poorly planned or in an unsuitable environment, risk of freezing, problems in cold winters and summers because the ground can’t regenerate (so drill deeper?)
- who has experience with drill depths over 150m (500 feet)? It was recommended to us
Air-source heat pump:
- mostly negative reports
- poor efficiency in winter, leading to higher electricity consumption, costs skyrocket!!! or it doesn’t get warm enough
- adjustment and setting issues, professionals and heating installers overwhelmed
- apparently complicated calculations on where and how much underfloor heating should be installed, with extra insulation and wall heating in the bathroom, still needing support from the heating unit and electricity
- then the outdoor unit is too noisy and causes conflicts with neighbors
- always something broken and nobody responds
- can anyone share good experiences with this?
- it is often recommended by prefab house providers because it is “cheap” and then there is still money left for other things?
- are expensive units significantly better than cheap ones?
- I really don’t want to post heating curves or have discussions about adjustment options, I simply want it to be warm and stay warm. Why is that such a problem with this system?
Question about ventilation:
- when is it absolutely recommended? Already at KfW55?
- In principle, I like ventilation systems with heat recovery (being at work all day, constant airing is a problem!), but I have serious nasal issues and fear the biggest difficulties in winter with dry rooms. There are humidification systems – how advisable are they?
- How about the risk of bacterial growth in the duct systems?
- At a prefab house exhibition park we noticed that even the supposedly well-ventilated houses smell musty by 11 a.m., just after the park opens. Not very pleasant.
You’d think everything would be great with renewable energy and then it’s just difficulties everywhere you look.
For us, the purchase of the plot depends heavily on this. The ecological aspect is definitely important, and we are willing to invest accordingly, but we don’t want to be cold because of it...
I look forward to clear and understandable contributions, as I am still a complete beginner.
I’d prefer to clarify things beforehand to avoid a nasty surprise later on.
Thank you very much for your effort!
Best regards, Anni
I have been quietly reading along from time to time, but now I feel compelled to ask a question myself (bravely).
We don’t yet have a plot of land or a house but are very interested. Everywhere you look and listen, there are contradictory statements depending on who is trying to sell what. It’s clear there is no one perfect heating system; each has its advantages and disadvantages, but it is all really confusing. Therefore, I am interested in your experiences, please also the positive ones!
Our plot will be about 1000m2 (0.25 acres), currently we have one in sight. The house should be about 160 to 180m2 (1700 to 1900 square feet). Which energy efficiency standard (KfW level) is still unclear. Location: southern Lower Saxony, a bit of a low mountain region, not a water protection area.
Unfortunately, there is no natural gas supply there, otherwise we would have chosen a condensing boiler.
I find a liquefied petroleum gas (LPG) tank in the garden unattractive – and I don’t know if it’s possible to have it underground, but I don’t like the idea of “refueling” either; I didn’t like that when we had an oil heating system before either...
Right now, the ground source heat exchanger with deep geothermal drilling is the most interesting option for us.
I’ve already done some research on soil conditions (talked to geologists):
- Limestone, clay, gypsum, no anhydrite; little water exchange, so a groundwater heat pump is probably out of the question, deep drilling should be possible but not easy. The deeper, the better.
The couple next door just built, and because of the water situation, they decided against a basement. A pity but not a big deal.
Wish:
-> The bathroom should be able to reach 24°C (75°F) – I’m really sensitive to cold!! Freezing in winter is truly a no-go for me – just how I am...
Now to a summary of the information I have gathered so far – it is very confusing for us:
Geothermal:
- 40 to 100m (130 to 330 feet) drilling depth, the deeper the better, but of course more expensive
- good efficiency, provided everything works out
- no clear information on durability, problems with earth movements causing pump failure; a representative from a prefab house company said they no longer offer geothermal systems because of many returns and dissatisfied customers, given the high costs!
- if poorly planned or in an unsuitable environment, risk of freezing, problems in cold winters and summers because the ground can’t regenerate (so drill deeper?)
- who has experience with drill depths over 150m (500 feet)? It was recommended to us
Air-source heat pump:
- mostly negative reports
- poor efficiency in winter, leading to higher electricity consumption, costs skyrocket!!! or it doesn’t get warm enough
- adjustment and setting issues, professionals and heating installers overwhelmed
- apparently complicated calculations on where and how much underfloor heating should be installed, with extra insulation and wall heating in the bathroom, still needing support from the heating unit and electricity
- then the outdoor unit is too noisy and causes conflicts with neighbors
- always something broken and nobody responds
- can anyone share good experiences with this?
- it is often recommended by prefab house providers because it is “cheap” and then there is still money left for other things?
- are expensive units significantly better than cheap ones?
- I really don’t want to post heating curves or have discussions about adjustment options, I simply want it to be warm and stay warm. Why is that such a problem with this system?
Question about ventilation:
- when is it absolutely recommended? Already at KfW55?
- In principle, I like ventilation systems with heat recovery (being at work all day, constant airing is a problem!), but I have serious nasal issues and fear the biggest difficulties in winter with dry rooms. There are humidification systems – how advisable are they?
- How about the risk of bacterial growth in the duct systems?
- At a prefab house exhibition park we noticed that even the supposedly well-ventilated houses smell musty by 11 a.m., just after the park opens. Not very pleasant.
You’d think everything would be great with renewable energy and then it’s just difficulties everywhere you look.
For us, the purchase of the plot depends heavily on this. The ecological aspect is definitely important, and we are willing to invest accordingly, but we don’t want to be cold because of it...
I look forward to clear and understandable contributions, as I am still a complete beginner.
I’d prefer to clarify things beforehand to avoid a nasty surprise later on.
Thank you very much for your effort!
Best regards, Anni
Also:
For the probe drilling, I recommend the company ixxx from Bovenden. They are reliable and also provide excellent advice beforehand.
For the heat pump (whether air-source or geothermal), you need a skilled heating engineer and a heating load calculation. The calculation itself isn’t difficult, but tradespeople are often poor at paperwork. Search for "There is no fire burning inside a heat pump." Many plumbers haven’t understood this yet. Then everything will work out. We have also switched from geothermal to an air-to-water heat pump, and the additional costs are not as high as sometimes stated.
Regarding the hydraulic balancing: I believe the occupants should definitely handle this themselves. It’s worthwhile, even if you’re not a perfectionist. No heating contractor can do it well because they are not constantly on site. Since underfloor heating is slow to respond, you should wait 24 hours after adjustment before deciding if it’s correct. In the bathroom, you will almost certainly need to install wall heating loops. Typically sized bathrooms simply do not have enough floor area compared to the heat demand. Be aware that prefab house builders often cannot manage wall heating.
For the probe drilling, I recommend the company ixxx from Bovenden. They are reliable and also provide excellent advice beforehand.
For the heat pump (whether air-source or geothermal), you need a skilled heating engineer and a heating load calculation. The calculation itself isn’t difficult, but tradespeople are often poor at paperwork. Search for "There is no fire burning inside a heat pump." Many plumbers haven’t understood this yet. Then everything will work out. We have also switched from geothermal to an air-to-water heat pump, and the additional costs are not as high as sometimes stated.
Regarding the hydraulic balancing: I believe the occupants should definitely handle this themselves. It’s worthwhile, even if you’re not a perfectionist. No heating contractor can do it well because they are not constantly on site. Since underfloor heating is slow to respond, you should wait 24 hours after adjustment before deciding if it’s correct. In the bathroom, you will almost certainly need to install wall heating loops. Typically sized bathrooms simply do not have enough floor area compared to the heat demand. Be aware that prefab house builders often cannot manage wall heating.
Good morning Domski,
thank you for taking the time to read my long message.
Your reply was already very helpful!
I plan to contact the company from Bovenden starting Monday, as the manager is not available this week.
I understand your explanation about the hydraulic balancing and feel relieved.
How large would a bathroom need to be for underfloor heating alone to be sufficient, without wall heating? Thanks for the tip about wall heating—I haven’t seen or heard about it in the prefabricated house park either.
The link you provided was interesting as well; I will now make sure the heating pipes are also installed under the bathtub.
And how is your mechanical ventilation with heat recovery (MVHR) working? Are you fully satisfied? Which system do you have?
Thanks!
thank you for taking the time to read my long message.
Your reply was already very helpful!
I plan to contact the company from Bovenden starting Monday, as the manager is not available this week.
I understand your explanation about the hydraulic balancing and feel relieved.
How large would a bathroom need to be for underfloor heating alone to be sufficient, without wall heating? Thanks for the tip about wall heating—I haven’t seen or heard about it in the prefabricated house park either.
The link you provided was interesting as well; I will now make sure the heating pipes are also installed under the bathtub.
And how is your mechanical ventilation with heat recovery (MVHR) working? Are you fully satisfied? Which system do you have?
Thanks!
Especially regarding air-to-water heat pumps, there are quite a few clichés, many of which also apply to ground-source (brine-to-water) heat pumps. Unless you have a builder who only installs gas condensing boilers, most of these issues are already solved. Certainly, air-to-water heat pumps use a bit more electricity in winter, but after nine months, I can conclude that this is not a problem for us at all. We still achieve an annual performance factor above 4.
We have a KfW55 house with a very simple underfloor heating system in the bathroom plus a towel radiator, and we can comfortably maintain 24°C (75°F). The pipe spacing is quite narrow, but that’s standard practice.
The hydraulic balancing is not a big deal and should be done for every heating system. Adjusting the heating curves is also not rocket science. In our system, there are two parameters, and the manual explains what can be done.
Regarding ventilation:
I wouldn’t build without a central ventilation system anymore; everything else seems like an imperfect solution to me personally, though opinions vary. If you do install one, definitely choose one with humidity recovery, and then the issue should be settled. What would be prone to contamination otherwise?
We have a KfW55 house with a very simple underfloor heating system in the bathroom plus a towel radiator, and we can comfortably maintain 24°C (75°F). The pipe spacing is quite narrow, but that’s standard practice.
The hydraulic balancing is not a big deal and should be done for every heating system. Adjusting the heating curves is also not rocket science. In our system, there are two parameters, and the manual explains what can be done.
Regarding ventilation:
I wouldn’t build without a central ventilation system anymore; everything else seems like an imperfect solution to me personally, though opinions vary. If you do install one, definitely choose one with humidity recovery, and then the issue should be settled. What would be prone to contamination otherwise?
Hello,
Regarding geothermal energy:
There is also the option to install ground or trench collectors in the garden. With a 1000 sqm (10,764 sq ft) plot, this should be feasible. This is said to be quite manageable as a DIY project and relatively inexpensive. Our neighbors have a 620 sqm (6,675 sq ft) property, installed trench collectors themselves, and are very satisfied. However, I have no idea what their electricity costs are!
In general, heat pumps can be somewhat tricky to install, and many heating specialists seem to become overwhelmed quickly.
Regarding the air-to-water heat pump:
As you know, I’m not a fan of these noisy units, but they are not as bad as you describe. It really depends heavily on the qualifications of the heating contractor. There is a lot that can go wrong.
And yes, overall they are almost certainly more expensive than a gas heating system. But since gas is not an option for you, that’s a different matter.
Regarding ventilation:
At first, I was completely against it, but for various reasons, we eventually installed one and love it. I wouldn’t want to do without it.
We have a central controlled ventilation system with heat recovery and an enthalpy exchanger, which also recovers humidity. This helps maintain indoor humidity at around 40%, even in winter. The ducts won’t develop microbial growth. They remain bone dry because no condensation occurs inside. So, there is no basis for germ formation. Of course, dust can accumulate, but that’s what filters are for. Our incoming air passes through two fine dust filter stages, resulting in nearly pollen- and dust-free air inside the house. Very pleasant, and you even need to dust significantly less.
Tip: install a ground heat exchanger as well. Then the air will be preheated for free in winter and slightly cooled in summer, so you don’t bring warm air directly into the house. This won’t cool the house down, but it reduces overheating in summer.
Best regards,
Andreas
Regarding geothermal energy:
There is also the option to install ground or trench collectors in the garden. With a 1000 sqm (10,764 sq ft) plot, this should be feasible. This is said to be quite manageable as a DIY project and relatively inexpensive. Our neighbors have a 620 sqm (6,675 sq ft) property, installed trench collectors themselves, and are very satisfied. However, I have no idea what their electricity costs are!
In general, heat pumps can be somewhat tricky to install, and many heating specialists seem to become overwhelmed quickly.
Regarding the air-to-water heat pump:
As you know, I’m not a fan of these noisy units, but they are not as bad as you describe. It really depends heavily on the qualifications of the heating contractor. There is a lot that can go wrong.
And yes, overall they are almost certainly more expensive than a gas heating system. But since gas is not an option for you, that’s a different matter.
Regarding ventilation:
At first, I was completely against it, but for various reasons, we eventually installed one and love it. I wouldn’t want to do without it.
We have a central controlled ventilation system with heat recovery and an enthalpy exchanger, which also recovers humidity. This helps maintain indoor humidity at around 40%, even in winter. The ducts won’t develop microbial growth. They remain bone dry because no condensation occurs inside. So, there is no basis for germ formation. Of course, dust can accumulate, but that’s what filters are for. Our incoming air passes through two fine dust filter stages, resulting in nearly pollen- and dust-free air inside the house. Very pleasant, and you even need to dust significantly less.
Tip: install a ground heat exchanger as well. Then the air will be preheated for free in winter and slightly cooled in summer, so you don’t bring warm air directly into the house. This won’t cool the house down, but it reduces overheating in summer.
Best regards,
Andreas
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