ᐅ Planning Heating and Ventilation Systems for a KfW 40 Plus Single-Family Home
Created on: 30 Sep 2020 09:56
D
DaSch17
Hello everyone,
We have a planning meeting with the heating and ventilation engineer scheduled for October/November.
In preparation, I have been wondering what I should pay special attention to and what is important. I hope to receive some valuable planning tips for this very important trade.
Brief key information about the planned new build:
- 2 full floors, clear structural height per floor 2.85 m (9 ft 4 in)
- KfW 40 Plus standard
- Heated living area approximately 190 m² (2045 ft²)
- Additional heat source: fireplace in the living/dining/kitchen area about 60 m² (645 ft²)
- Floor plan: see post #254 in https://www.hausbau-forum.de/threads/efh-neubauvorhaben-von-tag-1-an-und-die-planung-beginnt.33766/page-43
The following information and requirements (in addition to the planning documents) have already been sent to the heating/ventilation engineer:
Heating technology:
- Split air-to-water heat pump or ground-source (brine-to-water) heat pump
- Eligible for BAFA funding
- Underfloor heating in all rooms (except garage with storage room) with a target temperature of 21-22°C (70-72°F) in all rooms and 22-23°C (72-73°F) in the bathrooms
- Smart grid compatible (for using photovoltaic electricity)
- Cooling function if possible
- Hot water storage tank sized for a household of 4 persons
Controlled residential ventilation:
- Cooling function or summer bypass
What should I pay special attention to? What tips do you have?
We have a planning meeting with the heating and ventilation engineer scheduled for October/November.
In preparation, I have been wondering what I should pay special attention to and what is important. I hope to receive some valuable planning tips for this very important trade.
Brief key information about the planned new build:
- 2 full floors, clear structural height per floor 2.85 m (9 ft 4 in)
- KfW 40 Plus standard
- Heated living area approximately 190 m² (2045 ft²)
- Additional heat source: fireplace in the living/dining/kitchen area about 60 m² (645 ft²)
- Floor plan: see post #254 in https://www.hausbau-forum.de/threads/efh-neubauvorhaben-von-tag-1-an-und-die-planung-beginnt.33766/page-43
The following information and requirements (in addition to the planning documents) have already been sent to the heating/ventilation engineer:
Heating technology:
- Split air-to-water heat pump or ground-source (brine-to-water) heat pump
- Eligible for BAFA funding
- Underfloor heating in all rooms (except garage with storage room) with a target temperature of 21-22°C (70-72°F) in all rooms and 22-23°C (72-73°F) in the bathrooms
- Smart grid compatible (for using photovoltaic electricity)
- Cooling function if possible
- Hot water storage tank sized for a household of 4 persons
Controlled residential ventilation:
- Cooling function or summer bypass
What should I pay special attention to? What tips do you have?
K1300S schrieb:
The heating engineer should know which one fits best.I am currently experiencing that some (many?) heating engineers actually don’t know the exact requirements. They tend to play it safe by oversizing. I just received a rejection for my tender due to requirements being too high for BAFA...
DaSch17 schrieb:
At first glance, it seems very affordable. So, for ventilation + heating + rough installation a total of 39.5 thousand euros minus about 11.0 thousand euros BAfA subsidy.
For the sanitary equipment, we have budgeted another 18 thousand euros including installation. I can answer that myself. The heating contractor contacted me again and said there is "something wrong" with the heating quote – probably the labor costs are still missing.
K1300S schrieb:
The uniSTOR is only intended for hot water, which makes sense, but I’m puzzled by the heating capacity of the proposed heat generators and the fact that two devices with different outputs are being offered. The heating contractor should know which one fits best.
I would also include an impressed current anode for the storage tank. It’s inexpensive, but you get peace of mind forever. That was my thought as well. I will definitely have an independent engineering firm carry out a heating load calculation.
I noted the impressed current anode (for corrosion protection, right?). Thanks.
Tolentino schrieb:
There’s still a compact buffer tank listed under the heat pump/uniSTOR sets and not as an alternative option... And what does that mean?
This was in response to @K1300S's comment that the Unistor is only for domestic hot water. That is correct, but there is also this compact buffer tank mentioned, and I’m not sure what its purpose is. From what I have read, buffer tanks are not very effective for heat pumps operating with standard underfloor heating and screed heating without additional heat sources. Therefore, I would ask what it is for and whether it is really necessary.
But be careful—asking too many questions drove my HVAC installer away!
But be careful—asking too many questions drove my HVAC installer away!
DaSch17 schrieb:
Noted regarding the impressed current anode (used for corrosion protection, right?). Thanks. Yes, exactly, it’s for corrosion protection. Vaillant’s hot water tanks are still “traditional” (that is, not stainless steel) and therefore require a sacrificial anode, which needs to be replaced every few years depending on water quality, or alternatively an impressed current anode powered externally, which lasts indefinitely and protects the tank.