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?
D
Daniel-Sp1 Nov 2020 18:48What else will be installed besides the heat pump?
You should have the room-by-room heat load calculation and the design calculation of the underfloor heating with the desired parameters done externally.
You should have the room-by-room heat load calculation and the design calculation of the underfloor heating with the desired parameters done externally.
Thank you for your feedback!
That sums it up pretty well.
Noted. Thank you.
Ah, okay. Now I have the exact term to look up. From what I understand, it’s already been installed. So maybe it’s better to leave it as is, right?
Okay. Understood. In other words, a misleading promise.
I’ll bring this up again. Most likely we’ll have the refrigerant lines installed now and maybe add the air conditioning later through a refrigeration technician. That would also make the option with the ground heat exchanger for the mechanical ventilation system obsolete.
Where did you have that done? Online?
Which model?
According to HB, you should be able to switch between mechanical ventilation with ground heat exchanger (summer) and mechanical ventilation without ground heat exchanger (winter).
What do you mean? Probably a hot water storage tank, since both the flexoTHERM and Arotherm only have 190-liter (50-gallon) tanks. In my opinion, that’s too small for a household of four. Other than that, just the mechanical ventilation with heat recovery.
Well, and photovoltaics. But that’s a different topic for now.
Do you have a recommendation?
Mycraft schrieb:
It definitely sounds like "we've always done it this way."
That sums it up pretty well.
Mycraft schrieb:
I would definitely at least have the bedrooms air-conditioned or have the refrigerant lines etc. installed during construction. For that, you wouldn’t even need a refrigerant handling certificate.
Noted. Thank you.
Mycraft schrieb:
You have to be very careful here. This is a ground heat exchanger for the mechanical ventilation with heat recovery, and if it’s not executed perfectly, you’ll end up with more problems than benefits.
Ah, okay. Now I have the exact term to look up. From what I understand, it’s already been installed. So maybe it’s better to leave it as is, right?
Mycraft schrieb:
Yes, it cools the floor. But it has hardly any effect on indoor air temperature and humidity. This has been discussed here and everywhere else many times. Sure, it’s basically free cooling, but it doesn’t cool what should be cooled to have a noticeable effect.
Okay. Understood. In other words, a misleading promise.
Mycraft schrieb:
An air conditioning system costs about the same initial investment and then produces around 200 euros in annual operating costs. But then you have the desired temperatures exactly where you want them.
I’ll bring this up again. Most likely we’ll have the refrigerant lines installed now and maybe add the air conditioning later through a refrigeration technician. That would also make the option with the ground heat exchanger for the mechanical ventilation system obsolete.
OWLer schrieb:
The result was that I had the heating load calculation and the floor heating layout planning done.
Where did you have that done? Online?
OWLer schrieb:
Now we’re also getting Wolf.
Which model?
T_im_Norden schrieb:
If you have heat recovery in the mechanical ventilation system, the ground heat exchanger is counterproductive anyway.
According to HB, you should be able to switch between mechanical ventilation with ground heat exchanger (summer) and mechanical ventilation without ground heat exchanger (winter).
Daniel-Sp schrieb:
What else will be installed besides the heat pump?
What do you mean? Probably a hot water storage tank, since both the flexoTHERM and Arotherm only have 190-liter (50-gallon) tanks. In my opinion, that’s too small for a household of four. Other than that, just the mechanical ventilation with heat recovery.
Well, and photovoltaics. But that’s a different topic for now.
Daniel-Sp schrieb:
You should outsource the room-by-room heating load calculation and the design calculation for the underfloor heating with the desired parameters.
Do you have a recommendation?
D
Daniel-Sp2 Nov 2020 08:49I did it myself, and then the heating engineer implemented it.
Searching for Hfrink and an Excel spreadsheet
Searching for Hfrink and an Excel spreadsheet
T
T_im_Norden2 Nov 2020 08:55I would not recommend using a ground heat exchanger due to hygiene concerns and because a controlled ventilation system with heat recovery can operate in both directions. This means that in summer, it removes heat from the incoming air, and in winter, from the outgoing air.
Regarding the Vaillant heat pump + Vaillant controlled residential ventilation: An advantage is that both units (aroTHERM plus + recoVAIR) can communicate with each other via BUS, allowing them to be jointly controlled for BAFA subsidies, which also makes the controlled residential ventilation eligible for funding.
This makes a big difference for me. Without this feature, I would not have been able to include the controlled residential ventilation.
This makes a big difference for me. Without this feature, I would not have been able to include the controlled residential ventilation.
Daniel-Sp schrieb:
I did it myself, and then the heating contractor implemented it.
Search for Hfrink and an Excel spreadsheet I just took a look at the spreadsheet. Sorry, but I’m completely lost. It’s too complicated for me.
Alternatively, I found an engineering firm that does the heating load calculation for new builds: a fixed price of 139 EUR. Plus floor heating system design starting at 35 EUR, and pipe network planning starting at 65 EUR. The reviews looked good so far. I think I’ll contact them.
Tolentino schrieb:
Regarding Vaillant heat pumps + Vaillant controlled mechanical ventilation: one advantage is that the two (aroTHERM plus + recoVAIR) can communicate via BUS and thus can be managed together for BAFA subsidies, making the controlled ventilation eligible for funding.
That makes a big difference for me. Without this, I wouldn’t have been able to include controlled ventilation. Great tip. Thanks! I’ll pass this on to my builder.
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