ᐅ Heating via ventilation system with heat pump

Created on: 9 Jun 2017 22:11
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Tobibi
Hello,

We are interested in a house that is currently for sale and are already in negotiations. We have now learned that there was a misunderstanding regarding the heating system. It is heated with a heat pump; until now, we thought there was underfloor heating. It has turned out that the heating is only provided through the central ventilation system, essentially using warm air. The seller presents this as a particularly high-quality heating system that was even more expensive. We would have found underfloor heating, at least in the bathroom, very comfortable.

Can anyone share information about this type of heating? What are its advantages and disadvantages?

The house was built in 2002 and has approximately 145 m² (1560 sq ft).

Tobi
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Alex85
10 Jun 2017 22:21
Viebrockhaus probably hasn’t invented a perpetual motion machine yet either. Heat recovery always involves some loss—where does the rest come from? Electrical appliances, occupants, solar gains—yes! That only works in a passive house. All others use electricity for heating.
Especially if an additional 2-3 kW are used for hot water. Even a passive house can barely manage that.
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DNL
10 Jun 2017 22:29
As mentioned: I am not interested in a fundamental discussion or the efficiency, but solely in the fact that exhaust air heat pumps exist as air-to-air and air-to-water systems. When heat pumps are mentioned in new buildings, they usually refer to air-to-water systems.
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Alex85
10 Jun 2017 22:30
Alright. Then these should definitely be considered a similar investment to an air-to-water heat pump (with outdoor air), since underfloor heating and related components are also involved.
However, I’m even less clear on why someone would want to do that. In that case, you could also just source the energy from outside.
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Nordlys
10 Jun 2017 22:31
That makes sense, Alex. But is such a house still healthy? It has to be completely airtight, ideally with windows sealed shut so that no one ever ventilates. And with a crawl space door to prevent any cold outside air from coming in. Ew, I imagine living in a house like that would be a nightmare. Pale people, looking fragile, huddled inside, comforting themselves by saying, yes, but we saved the world. It was worth it…[emoji28]
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Alex85
10 Jun 2017 22:35
Haha, that’s a good question. I think even a KfW house is already "hermetically" sealed in a general sense. The rest is mostly about measurement. But yes, Passive Houses designed using PHPP place special emphasis on airtightness, heat loss through insulation and thermal bridges, as well as passive energy input like solar gains, occupants, and electrical appliances. In my opinion, the high costs are mainly due to the paperwork rather than the building materials or craftsmanship.

As for feeling unwell during unconscious time spent in such a space, I’m inclined to doubt it. The few people I know with Passive Houses don’t look like Gollum; they get up at 5 a.m. and run around the lake. Idealists.
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Nordlys
10 Jun 2017 22:39
Oh? Are they really that uncomfortable to sleep in?
Five o’clock, ugh.