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?
There are rumors that, due to subsidies
Yes, the often mentioned 2-3 degrees less is always a factor because achieving more simply isn’t feasible. But it usually stays around those 2-3 degrees. However, a 2-3 degree difference at 20°C (68°F) outside feels very different than at 30°C (86°F) outside. This should always be kept in mind. And if you actually live in the house rather than being away most of the time or on vacation, those 2-3 degrees less are only achievable to a limited extent for a short period.
The heat accumulates despite all passive measures. It’s not just the sun; cooking or baking alone can warm up your house significantly.
Granted, the highest temperatures only occur on selected days, sometimes just a few weeks at most.
DaSch17 schrieb:Nowadays, with the imposed regulations and requirements, you have to consider cooling in addition to heating and ventilation in our climate. Summers can get very, very hot inside those tight plastic bags called KfW-XYZ houses.
Sorry, I didn’t know that was relevant.
Yes, the often mentioned 2-3 degrees less is always a factor because achieving more simply isn’t feasible. But it usually stays around those 2-3 degrees. However, a 2-3 degree difference at 20°C (68°F) outside feels very different than at 30°C (86°F) outside. This should always be kept in mind. And if you actually live in the house rather than being away most of the time or on vacation, those 2-3 degrees less are only achievable to a limited extent for a short period.
The heat accumulates despite all passive measures. It’s not just the sun; cooking or baking alone can warm up your house significantly.
Granted, the highest temperatures only occur on selected days, sometimes just a few weeks at most.
DaSch17 schrieb:The costs vary a lot depending on the heating contractor. You often read in forums that people end up spending four figures for these measures. That is pointless. For that price, it makes more sense to go for active cooling right away.
In your opinion, the costs and benefits are not proportional, right?
@Mycraft
Thank you for your critical view on the cooling issue. I will keep that in mind and simply weigh the cost-benefit. Besides the higher initial investment, cooling obviously also leads to increased operating costs.
However, an air conditioning system would not comply with the 40-plus standard.
For the heating and ventilation system mentioned in the first post, including underfloor heating, we have planned a budget of 40,000 EUR. Is that too much? Or rather too little?
Thank you for your critical view on the cooling issue. I will keep that in mind and simply weigh the cost-benefit. Besides the higher initial investment, cooling obviously also leads to increased operating costs.
However, an air conditioning system would not comply with the 40-plus standard.
For the heating and ventilation system mentioned in the first post, including underfloor heating, we have planned a budget of 40,000 EUR. Is that too much? Or rather too little?
N
nordanney30 Sep 2020 11:18DaSch17 schrieb:
However, an air conditioning system would not comply with 40-plus standards.The preparations would. And who is stopping you from retrofitting the air conditioning system after the construction is completed?DaSch17 schrieb:
@Mycraft
Thank you for your critical view on the cooling issue. I will keep that in mind and simply weigh the cost-benefit. Besides the higher initial costs, cooling naturally also leads to increased operating expenses.
However, an air conditioning system would not comply with the 40-plus standard.
We have budgeted 40,000 EUR for the heating and ventilation system mentioned in the first post, including underfloor heating. Is this too much? Or rather too little?It depends on the heating system. A ground-source heat pump with deep boreholes costs a significant amount. Mechanical ventilation with heat recovery would probably be around 12,000–15,000 EUR (13,000–17,000 USD). Cooling for both systems would be additional. It could be tight.
nordanney schrieb:
The preparations are already underway. And who’s stopping you from installing the air conditioning after the construction is completed? Smart
Bookstar schrieb:
40,000 is very tight; I don’t think that will be enough. Definitely not for a ground-source heat pump. Otherwise, I can only recommend installing a wood stove—it’s really great to have that radiant heat. Ybias78 schrieb:
It depends on the heating system. A ground-source heat pump with deep drilling costs quite a bit. Mechanical ventilation with heat recovery would probably be around 12,000 to 15,000. Cooling for both options would be extra. It could get tight. Sorry, my mistake.
The 40,000 is the budget for a split air-to-water heat pump. If it’s a ground-source heat pump, the drilling costs need to be added on top—so around 49,000 to 52,000.
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