ᐅ New Construction KfW55 House – Heating System Design, Conflicting Information
Created on: 5 Dec 2020 13:15
D
DE_Haus
Hello everyone,
I’ve been following the discussions here for a few days and decided to register today to share my current situation. My wife and I are planning our new build; the construction documents were submitted six weeks ago, and we are now waiting for the building permit/planning permission.
Currently, our plan is to work with an architect rather than a general contractor, so we have free choice among various heating and plumbing companies.
House details:
KFW55 standard
Flat roof, cubic design
Living area: 190 m² (including 2.5 m² (1 inch) balcony) so the actual living area is 187.5 m². The basement is 60.67 m², which includes 16.6 m² for technical rooms. Therefore, I would like to heat 187.5 + 34.99 m² (basement excluding technical rooms) = 222.5 m².
The thermal insulation certificate is currently being prepared, but an initial estimate of the heating demand has already been provided.
According to the KFW consultant and the first heating system quote, a Viessmann Vitocal 200-S AWB-E AC D09 would be sufficient to heat adequately at a 35°C (95°F) supply temperature, achieving an annual performance factor above 4.5 to qualify for subsidies. I have obtained not just one but several quotes to find the best offer with the same specifications. However, I’m running into a “medium-sized” problem here.
Statements from companies:
Each heating and plumbing company gives different opinions: “Viessmann is great, and we only work with that brand,” “Ochsner is the best choice,” “Weishaupt is top-notch quality,” and “Heliotherm is the secret favorite for air-to-water heat pumps.” Even worse, everyone thinks their technical solution is the best.
Other statements from the heating and plumbing companies include:
“The heating buffer tank ‘must be at least 300 liters (79 gallons),’”
“A buffer tank that is too large is not good,”
“A fresh water station is absolutely necessary to prevent legionella,”
“A fresh water station only makes sense in multi-family buildings,”
“Domestic hot water storage must be at least 300 liters (79 gallons),”
“You need an electric backup heater in the bathroom,”
“A backup heater is not necessary.”
By now, I’m more confused than at the beginning and don’t know what to believe anymore. However, most agreed on one point and offered an air-to-water heat pump with similar specifications.
This question has probably been asked hundreds of times and cannot be answered definitively since every system has its pros and cons. But which manufacturer currently stands out, offering units with low failure rates, good service, and high efficiency?
We want to install the heating unit outside the house and have already designated a suitable area, but it must comply with the required sound pressure limits for night operation.
We have a total of 5 rooms on the ground floor (bathroom, office, living/dining area, foyer, and a small pantry). We plan to have 6 or 7 heating circuits here: 1 for the bathroom, 1 for the office, 3 for the living/dining area, and 1 or 2 for the foyer including the stairwell.
On the upper floor, there are 7 rooms (hallway, child’s room 1, child’s room 2, second bathroom, utility room, main bathroom, master bedroom including wardrobe). We intend one heating circuit per room.
In the basement, there are 4 rooms (hallway, storage 1, storage 2, and technical room). We plan 3 heating circuits here as we will not heat the technical room.
Heating system quotes:
Weishaupt WWP LB 12-A R
Viessmann Vitocal 200-S AWB-E AC D09
Ochsner AIR Eagle 414 C11B G1-1
Heliotherm HP12L/10L-WEB (pending final calculation)
What is really necessary for the other components and the size of the storage tanks?
Hot water storage tank size?
Heating buffer tank size?
Fresh water station?
Pipe spacing for underfloor heating? 10 cm (4 inches) in the bathroom and 15 cm (6 inches) in other rooms?
Backup heater in the bathroom? We want a heater there anyway to dry towels, so that is no big issue for us.
Finally, regarding the costs... these are ONLY for the heating system including underfloor heating, insulation, and commissioning. Water pipes and drainage are NOT included.
1.) Weishaupt WWP LB 12-A R with 100 L (26 gallons) heating buffer tank, 300 L (79 gallons) domestic hot water storage tank, no fresh water station, with circulation pump, including 3 electric wall heaters, air and dirt separators, plus insulation and underfloor heating: 34,500 € net
2.) Company 1 offer: Viessmann Vitocal 200-S AWB-E AC D09, VitoCell 100W 200 L (53 gallons) heating buffer, Vitocell 100W 300 L (79 gallons) domestic hot water tank, no fresh water station, with circulation pump, including 3 electric wall heaters, dirt separator but no air separator, plus insulation and underfloor heating: 29,300 € net
3.) Ochsner AIR Eagle 414 C11B G1-1, Ochsner 320 L (85 gallons) domestic hot water tank, 200 L (53 gallons) separation tank PU200, no fresh water station, with circulation pump, including 3 electric wall heaters, dirt separator but no air separator, plus insulation and underfloor heating: 38,300 € net
4.) Company 2 offer: Viessmann Vitocal 200-S AWB-E AC D09, VitoCell 120E with 350 L (92 gallons) domestic hot water tank and 250 L (66 gallons) heating buffer, VitoTrans 353 fresh water station, with circulation pump, no 3 electric wall heaters, Viessmann dirt and air separators, plus insulation and underfloor heating: 29,800 € net
5.) Heliotherm offer pending.
I would appreciate any tips or advice on what is really necessary to heat our house because I am now totally overwhelmed… prices also vary significantly.
Thank you very much and have a nice St. Nicholas Day weekend!
Greetings from Hesse =)
I’ve been following the discussions here for a few days and decided to register today to share my current situation. My wife and I are planning our new build; the construction documents were submitted six weeks ago, and we are now waiting for the building permit/planning permission.
Currently, our plan is to work with an architect rather than a general contractor, so we have free choice among various heating and plumbing companies.
House details:
KFW55 standard
Flat roof, cubic design
Living area: 190 m² (including 2.5 m² (1 inch) balcony) so the actual living area is 187.5 m². The basement is 60.67 m², which includes 16.6 m² for technical rooms. Therefore, I would like to heat 187.5 + 34.99 m² (basement excluding technical rooms) = 222.5 m².
The thermal insulation certificate is currently being prepared, but an initial estimate of the heating demand has already been provided.
According to the KFW consultant and the first heating system quote, a Viessmann Vitocal 200-S AWB-E AC D09 would be sufficient to heat adequately at a 35°C (95°F) supply temperature, achieving an annual performance factor above 4.5 to qualify for subsidies. I have obtained not just one but several quotes to find the best offer with the same specifications. However, I’m running into a “medium-sized” problem here.
Statements from companies:
Each heating and plumbing company gives different opinions: “Viessmann is great, and we only work with that brand,” “Ochsner is the best choice,” “Weishaupt is top-notch quality,” and “Heliotherm is the secret favorite for air-to-water heat pumps.” Even worse, everyone thinks their technical solution is the best.
Other statements from the heating and plumbing companies include:
“The heating buffer tank ‘must be at least 300 liters (79 gallons),’”
“A buffer tank that is too large is not good,”
“A fresh water station is absolutely necessary to prevent legionella,”
“A fresh water station only makes sense in multi-family buildings,”
“Domestic hot water storage must be at least 300 liters (79 gallons),”
“You need an electric backup heater in the bathroom,”
“A backup heater is not necessary.”
By now, I’m more confused than at the beginning and don’t know what to believe anymore. However, most agreed on one point and offered an air-to-water heat pump with similar specifications.
This question has probably been asked hundreds of times and cannot be answered definitively since every system has its pros and cons. But which manufacturer currently stands out, offering units with low failure rates, good service, and high efficiency?
We want to install the heating unit outside the house and have already designated a suitable area, but it must comply with the required sound pressure limits for night operation.
We have a total of 5 rooms on the ground floor (bathroom, office, living/dining area, foyer, and a small pantry). We plan to have 6 or 7 heating circuits here: 1 for the bathroom, 1 for the office, 3 for the living/dining area, and 1 or 2 for the foyer including the stairwell.
On the upper floor, there are 7 rooms (hallway, child’s room 1, child’s room 2, second bathroom, utility room, main bathroom, master bedroom including wardrobe). We intend one heating circuit per room.
In the basement, there are 4 rooms (hallway, storage 1, storage 2, and technical room). We plan 3 heating circuits here as we will not heat the technical room.
Heating system quotes:
Weishaupt WWP LB 12-A R
Viessmann Vitocal 200-S AWB-E AC D09
Ochsner AIR Eagle 414 C11B G1-1
Heliotherm HP12L/10L-WEB (pending final calculation)
What is really necessary for the other components and the size of the storage tanks?
Hot water storage tank size?
Heating buffer tank size?
Fresh water station?
Pipe spacing for underfloor heating? 10 cm (4 inches) in the bathroom and 15 cm (6 inches) in other rooms?
Backup heater in the bathroom? We want a heater there anyway to dry towels, so that is no big issue for us.
Finally, regarding the costs... these are ONLY for the heating system including underfloor heating, insulation, and commissioning. Water pipes and drainage are NOT included.
1.) Weishaupt WWP LB 12-A R with 100 L (26 gallons) heating buffer tank, 300 L (79 gallons) domestic hot water storage tank, no fresh water station, with circulation pump, including 3 electric wall heaters, air and dirt separators, plus insulation and underfloor heating: 34,500 € net
2.) Company 1 offer: Viessmann Vitocal 200-S AWB-E AC D09, VitoCell 100W 200 L (53 gallons) heating buffer, Vitocell 100W 300 L (79 gallons) domestic hot water tank, no fresh water station, with circulation pump, including 3 electric wall heaters, dirt separator but no air separator, plus insulation and underfloor heating: 29,300 € net
3.) Ochsner AIR Eagle 414 C11B G1-1, Ochsner 320 L (85 gallons) domestic hot water tank, 200 L (53 gallons) separation tank PU200, no fresh water station, with circulation pump, including 3 electric wall heaters, dirt separator but no air separator, plus insulation and underfloor heating: 38,300 € net
4.) Company 2 offer: Viessmann Vitocal 200-S AWB-E AC D09, VitoCell 120E with 350 L (92 gallons) domestic hot water tank and 250 L (66 gallons) heating buffer, VitoTrans 353 fresh water station, with circulation pump, no 3 electric wall heaters, Viessmann dirt and air separators, plus insulation and underfloor heating: 29,800 € net
5.) Heliotherm offer pending.
I would appreciate any tips or advice on what is really necessary to heat our house because I am now totally overwhelmed… prices also vary significantly.
Thank you very much and have a nice St. Nicholas Day weekend!
Greetings from Hesse =)
bauenmk20205 Dec 2020 15:46From my own experience, I can say: give significant weight to the argument of "noise emissions." Our heat pump is quite loud, and I have now lowered the frequency so that it doesn’t run at full capacity as often.
Personally, based on my findings, I would now consider a groundwater heat pump. Especially in colder regions, this is more efficient than an air-to-water heat pump.
Otherwise, I have heard a Viessmann unit running at full capacity—or rather, I didn’t hear it. This manufacturer would be my favorite.
Personally, based on my findings, I would now consider a groundwater heat pump. Especially in colder regions, this is more efficient than an air-to-water heat pump.
Otherwise, I have heard a Viessmann unit running at full capacity—or rather, I didn’t hear it. This manufacturer would be my favorite.
H
HilfeHilfe5 Dec 2020 16:04Always choose a company where friends or acquaintances have had positive experiences. Our installer is now banned from the site.
T
T_im_Norden5 Dec 2020 18:25Have an external company calculate this for you.
Room-by-room heating load calculation
No buffer tank, no mixing valve
Supply temperature 30°C (86°F) or lower
Connection to the heating circuit distributor large enough
Piping sized adequately, 16/2 or 17/2 (mm)
Possibly underfloor heating in the bathroom.
OWL had this calculated by a company, and they did a good job.
Find a heating contractor who accepts a plan calculated by an external source.
See the issues Tolentio is having.
Room-by-room heating load calculation
No buffer tank, no mixing valve
Supply temperature 30°C (86°F) or lower
Connection to the heating circuit distributor large enough
Piping sized adequately, 16/2 or 17/2 (mm)
Possibly underfloor heating in the bathroom.
OWL had this calculated by a company, and they did a good job.
Find a heating contractor who accepts a plan calculated by an external source.
See the issues Tolentio is having.
The questions surprise me a bit, even though I am not an expert and prefer to avoid dealing with technical matters.
What will future tenders look like? 😱 😀
Regarding your questions:
Every company (not just heating) claims THEIR technology or solution is the best.
Fresh water station? I have never heard of that. Surely there must be a legionella prevention program even with air-to-water heat pumps?
Yes, but that should be sufficient. It doesn’t need to be bigger.
That depends on the floor area. You can’t generalize. If the bathroom is quite small (roughly 5-8sqm (54-86 sq ft)), then it might have trouble warming up.
A towel radiator does not provide heating, especially when covered with towels.
I would definitely follow that advice and also take @Nida35a’s suggestion seriously. I would generally reject the most expensive option. I have never heard anything bad about Viessmann.
They all heat anyway.
What will future tenders look like? 😱 😀
Regarding your questions:
DE_Haus schrieb:
and even worse, everyone thinks their technical solution is the best.
Every company (not just heating) claims THEIR technology or solution is the best.
DE_Haus schrieb:
a fresh water station is absolutely necessary to prevent legionella
Fresh water station? I have never heard of that. Surely there must be a legionella prevention program even with air-to-water heat pumps?
DE_Haus schrieb:
drinking water storage tank must be at least 300 liters
Yes, but that should be sufficient. It doesn’t need to be bigger.
DE_Haus schrieb:
In the bathroom, you need an electric auxiliary heater
That depends on the floor area. You can’t generalize. If the bathroom is quite small (roughly 5-8sqm (54-86 sq ft)), then it might have trouble warming up.
A towel radiator does not provide heating, especially when covered with towels.
DE_Haus schrieb:
however, it must comply with the necessary sound pressure levels for nighttime operation.
I would definitely follow that advice and also take @Nida35a’s suggestion seriously. I would generally reject the most expensive option. I have never heard anything bad about Viessmann.
They all heat anyway.
N
nordanney5 Dec 2020 18:55ypg schrieb:
Fresh water station? I've never heard of that. There must be a legionella program for air-to-water heat pumps as well, right?This is a very common water storage system. It separates the heating circuit from the potable water circuit. The water storage tank is heated by the heating system. Inside, there is a heat exchanger that warms the flowing fresh water. No legionella risk, since it is not a potable water storage tank. It’s a great solution, but slightly more expensive (should cost about 1,000–1,500 euros extra).Ötzi Ötztaler5 Dec 2020 19:03
HilfeHilfe schrieb:
Our installer is now banned from the house.What did he do to your heating system? Or was he in bed with your wife? :-pSimilar topics