ᐅ Mechanical ventilation with heat recovery vs. exhaust ventilation with heat recovery in KfW 40 standard construction
Created on: 7 Nov 2020 19:28
M
MaxiFrett
Hello everyone,
I am currently struggling with the question in the title.
Specifically, it concerns an offer from a general contractor. The offer includes a brine-to-water heat pump with an exhaust air module including heat recovery (both Nibe).
The contractor typically installs the exhaust air modules as standard, almost always regardless of the heating system.
This means an active central ventilation system for the bathroom and kitchen, with passive ventilation through flow grilles in the walls of the other rooms.
As an alternative, we could choose a controlled residential ventilation system. The additional cost would be about 3,500 EUR.
Now I am uncertain about which option would suit us better:
We have experience with a controlled residential ventilation system in a rental apartment and were very satisfied with the air exchange and noise performance.
I see the following advantages and disadvantages of the exhaust air solution with heat recovery:
- Cheaper
- Bedrooms are cooler in winter
- In summer, room heat can be used to heat water
Disadvantages:
- Holes in the walls and more prone to external noise – although according to the contractor, this is mainly an issue near busy roads or flight paths.
- I am worried about drafts/cold air in winter – which the contractor says does not occur, and I could not find any online sources confirming it either.
- I am unsure about the air exchange: I imagine the air always takes the shortest path -> exhaust air in the kitchen, so supply air will mostly come from the adjacent room and less from rooms further away.
On the other hand, I see the following advantages and disadvantages of controlled residential ventilation:
- Basically the standard
- Supply air is filtered -> grass/pollen – although this is not a major issue for us.
- We already know how it “feels”
Disadvantages:
- More expensive
- More ducts required -> possibly visible.
What do you think?
At first, I was in favor of controlled residential ventilation but have lately been warming up to the exhaust air solution.
Are there forum members with practical experience of the exhaust air solution who can dispel my concerns or fears?
I am currently struggling with the question in the title.
Specifically, it concerns an offer from a general contractor. The offer includes a brine-to-water heat pump with an exhaust air module including heat recovery (both Nibe).
The contractor typically installs the exhaust air modules as standard, almost always regardless of the heating system.
This means an active central ventilation system for the bathroom and kitchen, with passive ventilation through flow grilles in the walls of the other rooms.
As an alternative, we could choose a controlled residential ventilation system. The additional cost would be about 3,500 EUR.
Now I am uncertain about which option would suit us better:
We have experience with a controlled residential ventilation system in a rental apartment and were very satisfied with the air exchange and noise performance.
I see the following advantages and disadvantages of the exhaust air solution with heat recovery:
- Cheaper
- Bedrooms are cooler in winter
- In summer, room heat can be used to heat water
Disadvantages:
- Holes in the walls and more prone to external noise – although according to the contractor, this is mainly an issue near busy roads or flight paths.
- I am worried about drafts/cold air in winter – which the contractor says does not occur, and I could not find any online sources confirming it either.
- I am unsure about the air exchange: I imagine the air always takes the shortest path -> exhaust air in the kitchen, so supply air will mostly come from the adjacent room and less from rooms further away.
On the other hand, I see the following advantages and disadvantages of controlled residential ventilation:
- Basically the standard
- Supply air is filtered -> grass/pollen – although this is not a major issue for us.
- We already know how it “feels”
Disadvantages:
- More expensive
- More ducts required -> possibly visible.
What do you think?
At first, I was in favor of controlled residential ventilation but have lately been warming up to the exhaust air solution.
Are there forum members with practical experience of the exhaust air solution who can dispel my concerns or fears?
For just an additional 3500, I wouldn’t even consider anything other than a central controlled residential ventilation system. You’ve already mentioned the benefits.
Every extra hole in the wall is always a thermal bridge, and these should generally be avoided.
Your concerns about the ducts are unfounded.
Every extra hole in the wall is always a thermal bridge, and these should generally be avoided.
Your concerns about the ducts are unfounded.
D
Daniel-Sp7 Nov 2020 19:51If you choose a ventilation system, go for a proper central controlled residential ventilation with heat recovery.
Anything else is just a compromise solution, especially considering the minimal additional cost.
Anything else is just a compromise solution, especially considering the minimal additional cost.
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