Hello everyone,
we are choosing between two prefabricated house suppliers with different heating systems. I’m not very familiar with the topic, so I’m hoping for your opinions.
Basic data: living area of 150 sqm (1615 sq ft) on the ground floor and upper floor, plus 40 sqm (430 sq ft) heated basement.
Option 1: KfW 40 house with Proxon fresh air heat technology – an air-to-air heat pump.
Option 2: KfW 55 house with underfloor heating and Buderus air-to-water heat pump or Viessmann (Vitocal 242-S) air-to-water heat pump.
What do you think about the advantages and disadvantages of these technologies?
Best regards & thanks
we are choosing between two prefabricated house suppliers with different heating systems. I’m not very familiar with the topic, so I’m hoping for your opinions.
Basic data: living area of 150 sqm (1615 sq ft) on the ground floor and upper floor, plus 40 sqm (430 sq ft) heated basement.
Option 1: KfW 40 house with Proxon fresh air heat technology – an air-to-air heat pump.
Option 2: KfW 55 house with underfloor heating and Buderus air-to-water heat pump or Viessmann (Vitocal 242-S) air-to-water heat pump.
What do you think about the advantages and disadvantages of these technologies?
Best regards & thanks
B
boxandroof12 Apr 2019 22:30guckuck2 schrieb:
Domestic hot water production using an air-to-air heat pump is a nightmare, as the electricity meter spins with every bath. In the end, the total of heating and hot water consumption matters, and it is almost irrelevant that the efficiency is lower during hot water production than for heating.
Every type of heat pump has this issue, and as far as I know, the efficiency of gas boilers for hot water production is not ideal either.
guckuck2 schrieb:
expect that option to be 10,000€ cheaper. Yes, for the seller—that’s why they offer it.
You just need to check online, and you’ll find many homeowners complaining about their electricity bills. It’s often around 1,000€ (about 1,100 USD) more per year than necessary. Without sufficient heating surfaces, this is hardly manageable.
I’m not saying it can’t be done purely with air, but certainly not with a large prefab home provider. Even for KfW 40 standard houses, I would only consider it if I knew exactly what I was doing.
B
boxandroof12 Apr 2019 22:32Bookstar schrieb:
If possible, go with gas. Definitely with provider 1.
A well-designed heat pump makes more sense in new construction, unless it is offered at an inflated price or if insulation can be reduced because of the heat pump, as it would still meet KFW 55 standards this way.
B
boxandroof12 Apr 2019 22:45haydee schrieb:
Why is blown-in warm air uncomfortable? Because only a small amount of heat energy can be transferred through the air. In a house < Passive House, this means increased airflow volume and/or high air temperatures. The latter further reduces efficiency.
By the way, I just realized why you mentioned in another thread that exhaust air rooms feel colder 🙂
haydee schrieb:
@guckuck2
Why is blown warm air uncomfortable?boxandroof provides the main answer.
Additionally, consider this counter question: which do you prefer—heat from a fireplace or heat from the car’s ventilation? It’s a bit rhetorical, but the basic principle applies.
When heat is provided by preheated air, you always get uneven air temperatures. This is uncomfortable. It’s similar to people complaining about cold air conditioning on airplanes or feeling cold near an open window. The difference here is that it concerns warmth, not cold.
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