Gas and Controlled Residential Ventilation

Dear forum members,

I have been reading here for a few days and feel like my head is going to explode ;) This is really very informative and I am very glad I came across this before signing! However, I feel that there is no solution for our "problem."
A short introduction about us: We have reserved a plot and have more or less finally decided on a builder who will build us a 1.5-story solid single-family house that can accommodate 6 people. We have chosen gas, but with underfloor heating and good insulation, so that later we might be able to switch to a heat pump as a heat source. The primary offer included a geothermal heat pump plus controlled residential ventilation as an exhaust air system with heat recovery to the brine circuit and decentralized supply air. We would very much like to install ventilation, preferably – regarding hygiene and maintenance effort – one with central exhaust and decentralized supply air. But heat recovery from the exhaust air to the domestic hot water seems only possible with an exhaust air heat pump, right? That is probably extremely expensive and also not sensible, right? I would be very happy for your tips on how you solved this problem, for example!

Best regards,
Mecc

Hello,

..... We decided on gas, but with underfloor heating and good insulation to possibly switch to a heat pump as a heat generator later on.

Not a bad decision for the future.

..... one with central exhaust and decentralized supply air.

That is actually the standard case and usually common. Why shouldn’t that work here?

..... But heat recovery from the exhaust air to the domestic hot water seems only possible with an exhaust air heat pump, right?

Why necessarily domestic hot water production using an additional heat pump, when a gas condensing boiler is planned? A separation of heat generation for heating and domestic hot water is usually only necessary in exceptional cases. For a normal single-family house, one heat generator serving both areas is generally sufficient.
Heat recovery from the exhaust air benefits the central supply air. For example, at -14°C outside temperature, you might have supply air temperature of about 12°C. Considerably more comfortable than, for example, the low supply air temperatures with decentralized supply air.
If already controlled residential ventilation/heat recovery, then properly. Most people build only once, so "half-truths" make little sense.

Best regards.

Hello €uro,

thank you very much for your reply! The thought about hot water heating only came up because with decentralized supply air the heat cannot be transferred to the supply air. And somewhere it has to go, simply blowing it into the atmosphere also seems like a waste. But you mean, if controlled residential ventilation, then properly. So central supply air as well? We are just concerned about the maintenance costs of a central system, and apparently so much can go wrong with miscalculations, missing silencers, and so on. Our BU also warns about the hygienic disadvantages of the central version due to different temperatures of wall, pipe, and air, which would probably lead to condensate formation. Sounds like a good breeding ground...

Best regards, Mecc

Hello,

...Only have respect for the maintenance costs of a central system, besides so much can apparently go wrong with calculation errors, missing silencers, etc. Our BU also warns about the hygienic disadvantages of the central version due to different temperatures of wall, pipe, and air, which would probably lead to condensate formation. Sounds like a good breeding ground...

Well, every GU/GÜ has their concept which they want to sell. Deviations from this are not welcome ;-) Accordingly, the evaluation of corresponding alternatives also turns out that way ;-)

best regards

Hi €uro, yes, that's probably true! You have to double-check everything, not so easy... We just hope that he still installs it properly! best regards, Mecc

PS Yes I know! Whether hope is the right basis for such a significant investment as building a house... ;)