Hello everyone
We are currently taking the next steps toward building our own home. We have looked at several prefabricated houses and spoken with sales consultants from various providers. Based on this, we have created a top 5 list. Now I want to contact these 5 companies with our floor plan and the standards we want. This way, I hope the list will be reduced by 2-3 providers after receiving the first offers.
In my inquiry, I want to roughly outline what we have in mind. KFW55, KFW40, or KFW40+ is not yet very important—it will be one of these standards. Our floor plan does not differ much from the standard layouts offered by prefab house suppliers. Something like a simple 8x10 meter (26x33 feet) rectangular shape... To be able to compare the 5 offers reasonably, I want them all to be as similar as possible. Therefore, I would like to specify the heating system.
Now the question is, what is the right choice… I assume this is partly a matter of philosophy? The options are an air-to-water heat pump, an air-to-air heat pump, or a ground-source (geothermal) heat pump. I assume most have one of these three systems combined with solar panels on the roof.
My first thought was this: an air-to-air heat pump, since we would also have an automatic ventilation system in the house, making manual airing less or unnecessary. However, I have learned that all KFW-certified houses are so well insulated that they almost always have automatic ventilation. So this argument is no longer valid. Nevertheless, I still find the air-to-air heat pump interesting. We also want to install a wood stove in the living room. With an air-to-air heat pump, the indoor air is circulated throughout the house, so I could benefit from the wood stove’s heat everywhere, right? Perhaps even with heat recovery, which is usually included.
Another advantage of the air-to-air heat pump would be that if it ever gets too warm, we could install a fixed air conditioning unit somewhere in the house, and the whole house would benefit. The built-in cooling systems in these heat pumps usually aren’t as effective as promised.
Is it true that an air-to-air heat pump cannot provide domestic hot water? Then a second system would be needed just for hot water, which means more costs, two systems to maintain, and more space taken up. In the forum, I mostly see air-to-water heat pumps mentioned, probably combined with underfloor heating. That seems to be the most popular system. Is there a particular reason for this?
Geothermal heating combined with a heat pump seems to be the most efficient. But then I would also have underfloor heating, right? We actually didn’t want underfloor heating, but as I’m writing this, I’m starting to convince myself toward geothermal or air-to-water heat pumps…
How did you make your decision and why? Somehow, I don’t fully trust the salespeople, since they want to sell what makes more money, right? And since I’m not very technical in this area, I’m hoping to benefit from your experience.
Best regards Andreas_79
We are currently taking the next steps toward building our own home. We have looked at several prefabricated houses and spoken with sales consultants from various providers. Based on this, we have created a top 5 list. Now I want to contact these 5 companies with our floor plan and the standards we want. This way, I hope the list will be reduced by 2-3 providers after receiving the first offers.
In my inquiry, I want to roughly outline what we have in mind. KFW55, KFW40, or KFW40+ is not yet very important—it will be one of these standards. Our floor plan does not differ much from the standard layouts offered by prefab house suppliers. Something like a simple 8x10 meter (26x33 feet) rectangular shape... To be able to compare the 5 offers reasonably, I want them all to be as similar as possible. Therefore, I would like to specify the heating system.
Now the question is, what is the right choice… I assume this is partly a matter of philosophy? The options are an air-to-water heat pump, an air-to-air heat pump, or a ground-source (geothermal) heat pump. I assume most have one of these three systems combined with solar panels on the roof.
My first thought was this: an air-to-air heat pump, since we would also have an automatic ventilation system in the house, making manual airing less or unnecessary. However, I have learned that all KFW-certified houses are so well insulated that they almost always have automatic ventilation. So this argument is no longer valid. Nevertheless, I still find the air-to-air heat pump interesting. We also want to install a wood stove in the living room. With an air-to-air heat pump, the indoor air is circulated throughout the house, so I could benefit from the wood stove’s heat everywhere, right? Perhaps even with heat recovery, which is usually included.
Another advantage of the air-to-air heat pump would be that if it ever gets too warm, we could install a fixed air conditioning unit somewhere in the house, and the whole house would benefit. The built-in cooling systems in these heat pumps usually aren’t as effective as promised.
Is it true that an air-to-air heat pump cannot provide domestic hot water? Then a second system would be needed just for hot water, which means more costs, two systems to maintain, and more space taken up. In the forum, I mostly see air-to-water heat pumps mentioned, probably combined with underfloor heating. That seems to be the most popular system. Is there a particular reason for this?
Geothermal heating combined with a heat pump seems to be the most efficient. But then I would also have underfloor heating, right? We actually didn’t want underfloor heating, but as I’m writing this, I’m starting to convince myself toward geothermal or air-to-water heat pumps…
How did you make your decision and why? Somehow, I don’t fully trust the salespeople, since they want to sell what makes more money, right? And since I’m not very technical in this area, I’m hoping to benefit from your experience.
Best regards Andreas_79
If you need to regulate an underfloor heating system, it means there was a mistake in the design, the hydraulic balancing is missing, or the shading concept is incorrect. Otherwise, you just turn it on once a year and off once a year. And this even happens automatically. With the highest level of comfort.
RotorMotor schrieb:
@Acof1978 You keep repeating that people shouldn't build at all. Obviously, building impacts the environment, and a single-family house more than an apartment block. But many people simply won’t consider giving up building. Therefore, the focus should be on choosing the “right energy concept” within that preference—one that causes the least environmental harm without significant loss of comfort. Why is giving up building not an option? Just because you want your own land? There are few concrete (I’d say no) environmentally conscious reasons to decide to build a house.
Let me give you another example: external blinds or roller shutters. People design bright, open spaces only to darken them in summer (which surprises us every year). This consumes many materials and electricity… Or they install air conditioning, which uses considerable power. The excuse, “we have solar panels,” doesn’t hold either, since those don’t just appear out of thin air.
I could give many more examples from others who now complain about fireplaces—things like insulation, plastic flooring (vinyl), 80-inch TVs instead of 55-inch, extensive sealed surfaces, small natural gardens, and so on.
One shouldn’t pick out small details to criticize but perhaps consider the bigger picture.
Has anyone seen statistics comparing what is better environmentally: heating with a fireplace using wood constantly, or using a ground-source heat pump supported by solar panels, and then using the fireplace only 10–20 times a year as a decorative fire?
rdwlnts schrieb:
If you need to regulate a floor heating system, it means there was a mistake in the design, the hydraulic balancing is missing, or the shading concept is incorrect. Otherwise, you just turn it on once a year and off once a year. And this happens automatically. With the highest comfort. Correct. In our case, each room is individually set to 19-21°C (66-70°F). A hydraulic balancing is performed by the construction company. @Bookstar So you have underfloor heating and also heat with a fireplace. You ENVIRONMENT KILLER!!!
M
Myrna_Loy31 Jul 2021 08:57Acof1978 schrieb:
So why did you build a house then? It’s totally wrong ecologically if you care about the environment. Considering a) land use, b) soil sealing (concrete slab), and c) material consumption... it’s better to live in a modern apartment building.
What was that saying about people in glass houses throwing stones? We didn’t build a new house; we are renovating a house that is over 200 years old. Using ecological building materials where possible, recycling where we can, and using local building materials and craftsmanship whenever possible.
Shocking, I know.
Myrna_Loy schrieb:
We didn’t build new; we are renovating a house that is over 200 years old. Using ecological building materials where possible, recycling where we can, and sourcing local building materials and craft services whenever we can.
Shocking, I know.Nevertheless, it would be more environmentally sensible to build an apartment building for multiple households there instead of a single-family home. You can justify anything, but single-family houses are generally less eco-friendly than apartment buildings with the same construction method. Besides, an old house will never be as energy-efficient as a new build.
As I said before: greenhouses and bricks...
M
Myrna_Loy31 Jul 2021 09:43Acof1978 schrieb:
Despite everything, it would be more ecological to build an apartment block for multiple households there, rather than a single-family home. You can sugarcoat it all you want, but single-family houses are simply less eco-friendly than apartment blocks when built with the same construction method. Not to mention that the old house won’t be as energy efficient as a new build.
As already mentioned—glass house and stones...No, apples and oranges. But go ahead and convince yourself that your outdoor space heater disguised as a stove is something else. 😀Similar topics