Construction of an approximately 190 sqm city villa in Hessen (Wetteraukreis)

We have the exterior walls made of 42cm Liaplan, the interior walls made of 11cm KS (calcium silicate brick), the alternative would have been 17cm Liaplan. Our technical room is located between the guest WC and bathroom, no wall to living or sleeping rooms. We do not hear anything from the heat pump. We have high-quality doors, the standard from the general contractor was not enough for us. We have the contact details of all regional subs, after moving in we had a descaling system and some electrical additions installed.

Oberhessengas offers ground source heat pumps for the new development area without an acquisition cost through monthly installments. Would that be an alternative?

Geothermal energy is definitely recommended. And the heat pump - at least our model from Nibe - is whisper quiet.
What about controlled residential ventilation? Did I miss something there?

Thanks for the tip! In the development area, internal air-to-water heat pumps are unfortunately mandatory. We now want to decide on the first regional provider. My wife definitely wants a house made of stone, and we fully agree with the recent posts here about regional providers. Specialist companies from the region usually deliver very good results and are presumably also easier to reach for inquiries. Regarding your point: With solid construction using Liapor in monolithic form, the internal air-to-water heat pump should fit, right? Next to the utility room are the WC and kitchen. Above the utility room on the upper floor is the bathroom. I also found the noise of internal heat pumps frightening in show houses. But even in the timber frame houses, it was inconspicuous with the door closed. However, you don't sit quietly for hours in the neighboring room there. Do you also see a problem with noise and vibrations from the Liapor walls? Oberhessengas offers geothermal heat pumps without an acquisition cost in the new development area through monthly installments. Would that be an alternative? Or consider the additional costs of a geothermal heat pump despite the current prices for earthworks? Does it actually produce less noise in the utility room?

With the geothermal heat pump, you don't have the ugly device that causes noise. There are two options for geothermal heat pumps. Either you use deep drilling (then the area must not be in a water protection zone) or you work with surface collectors or ring trench collectors. For the latter, you need a larger plot. We had to decide on the second alternative. But keep in mind that heat pumps are currently in short supply. We ordered ours in February, and there is still no delivery date. So order early enough.

We have the exterior walls made of 42cm Liaplan, the interior walls made of 11cm KS (lime sand brick), alternatively it could have been 17cm Liaplan.
Our technical room is between the guest WC and the bathroom, no wall to living or sleeping rooms.
We don’t hear anything from the heat pump.
We have high-quality doors, the standard from the general contractor was not enough for us.
We have the contact details of all the regional subcontractors; after moving in, we had a descaling system and some electrical additions installed.

Great, thanks. We currently have 49.5 cm Liapor planned for exterior and 17.5 cm or 10 cm Liapor for interior walls, depending on the wall.
Then the heat pump might be okay after all.
There are sure to be smaller follow-up orders from time to time, and then you already have companies lined up.

Geothermal energy is definitely recommended. And the heat pump – at least our model from Nibe – is whisper quiet.
What about controlled residential ventilation? Did I overlook something?

I will now get the offer for the “flat rate” and compare it with the costs of immediate payment for geothermal systems. Thanks!

I once considered controlled residential ventilation as optional – but everything I have read so far rather suggests that you don’t want to do without it. Despite solid construction and KFW 55. In our case, it would be about 12,000 euros that could have been “saved.” Expensive luxury or mandatory? The advantages from the heat exchange of supply and exhaust air would probably be less decisive with geothermal energy, I think?

With the geothermal heat pump, you don’t have the ugly device that causes noise. There are two options with geothermal heat pumps. Either you do it via deep drilling (then the area must not be in a water protection zone) or you work with surface or trench collectors. But then you need a larger plot. We had to decide on the second alternative. But keep in mind that heat pumps are currently in short supply. We ordered ours in February and there is still no delivery date. So order early enough.

That sounds great. Even if it’s only the washing machine you want to operate in the utility room. But overall, I am a big fan of reducing noise emissions, so that sounds ideal.
Deep drillings should be possible, but I have to check that. Our plot with 750 sqm should be sufficient even without deep drilling. In the package from Oberhessengas, they talk about “geo collectors” that are laid in the ground. I will arrange the consultation appointment and then I will know more about the possible installment solution.
Yes, the shortage is known to me. Oberhessengas would hopefully manage that as a large provider. Our regional general contractor would certainly order in time. By the way, they currently build their houses in 9 months. I can hardly believe that, but then moving in is planned for next summer. Christmas 2023 would be enough for me, we have good rent-free interim solutions on site.

Thanks to everyone for the valuable tips! The decisions are much easier thanks to your advice and experiences!

I once considered controlled residential ventilation optional – but everything I have read so far suggests that you really don’t want to do without it. Despite solid construction and KFW 55. For us, it would have been about 12,000 euros that could have been "saved". Expensive luxury or mandatory? The advantages of heat exchange between supply and exhaust air would probably be less decisive with geothermal energy, I think?

Well, let’s put it this way, the topic of controlled residential ventilation is very controversially discussed here. I can only speak from my own experience. And it says: mandatory. The tighter the house, the greater the need for air exchange, especially in the seasons when the balcony door is not always open. And probably no one likes to walk through the whole house twice a day to ventilate. Not to mention the air you find in your beloved home after three weeks of vacation without controlled residential ventilation.
Heat recovery is always an issue, no matter how I heat the house. The heat should stay inside. And it doesn’t matter how it was generated.

Well, let's put it this way, the topic of controlled residential ventilation is very controversially discussed here. I can only report from my experience. And it says: mandatory program. The tighter the house, the greater the need for air exchange, especially in the seasons when the balcony door is not always open. And probably no one likes to walk through the whole house twice a day to air out. Not to mention the air you find in your beloved home after three weeks of vacation without controlled residential ventilation. Heat recovery remains a topic, no matter how I heat the house. The heat should stay inside. And it doesn't matter how it was generated.

Yes, I completely agree with you. Just the possible risk of mold due to tight construction is, for me, an argument not to omit controlled residential ventilation. Thanks for thinking along! I will soon send you some floor plans as well. I currently don’t have any up-to-date high-quality ones, there’s still scribbling on them, and discussing outdated ones probably makes little sense. There is certainly still something to optimize.