ᐅ New Construction + Exhaust Air Heat Pump According to Provider, Is a Trench Collector Affordable?
Created on: 13 Mar 2016 16:19
E
expose
Hello,
I am currently working on a new construction project that is approaching the final stages, except for the heating system. Originally, a gas boiler with solar support for domestic hot water was planned. This would make the house comply with the KfW 70 energy standard. It is a bungalow with 125 m² (1345 sq ft) of living space (4 rooms, kitchen integrated into the living area, bathroom, toilet, utility room) on an 835 m² (8980 sq ft) plot.
The builder has now proposed an exhaust air heat pump with decentralized ventilation. The additional costs, including extra insulation of the floor slab to meet the KfW 55 standard, are around 6,000–7,000 euros. In principle, I like the idea of being independent from fossil fuels, but after looking closely at such a heating system, I am not completely convinced by the concept. Especially the ventilation seemed questionable to me, as there was a noticeable cold draft and the rooms felt somewhat stuffy overall.
The builder himself has no experience with these heat pumps yet but plans to install several in the future.
During my research on exhaust air heat pumps, I also came across heat pump technology with ground loop collectors and find this concept much more interesting.
The fact is, the extra cost compared to the gas boiler, about 6,000–7,000 euros, represents the upper limit of my budget. It must not get more expensive.
I am a bit unsure about how to proceed. How can I determine whether a ground loop collector would be suitable, and whether it would fit my budget? Are there possibly other heat pumps with external units that might be an option? Or could my concerns about the exhaust air heat pump be unfounded?
Thank you in advance.
I am currently working on a new construction project that is approaching the final stages, except for the heating system. Originally, a gas boiler with solar support for domestic hot water was planned. This would make the house comply with the KfW 70 energy standard. It is a bungalow with 125 m² (1345 sq ft) of living space (4 rooms, kitchen integrated into the living area, bathroom, toilet, utility room) on an 835 m² (8980 sq ft) plot.
The builder has now proposed an exhaust air heat pump with decentralized ventilation. The additional costs, including extra insulation of the floor slab to meet the KfW 55 standard, are around 6,000–7,000 euros. In principle, I like the idea of being independent from fossil fuels, but after looking closely at such a heating system, I am not completely convinced by the concept. Especially the ventilation seemed questionable to me, as there was a noticeable cold draft and the rooms felt somewhat stuffy overall.
The builder himself has no experience with these heat pumps yet but plans to install several in the future.
During my research on exhaust air heat pumps, I also came across heat pump technology with ground loop collectors and find this concept much more interesting.
The fact is, the extra cost compared to the gas boiler, about 6,000–7,000 euros, represents the upper limit of my budget. It must not get more expensive.
I am a bit unsure about how to proceed. How can I determine whether a ground loop collector would be suitable, and whether it would fit my budget? Are there possibly other heat pumps with external units that might be an option? Or could my concerns about the exhaust air heat pump be unfounded?
Thank you in advance.
G
Goldi0911114 Mar 2016 22:42I’m facing the same question, but I tend to lean clearly towards gas because, in my opinion, all the calculations look good, and in most cases, you can potentially recover the extra cost within 30 years.
No one can really predict today where gas or electricity prices will be in 30 years. Overall, it’s a matter of personal preferences and having a “green thumb.”
No one can really predict today where gas or electricity prices will be in 30 years. Overall, it’s a matter of personal preferences and having a “green thumb.”
Due to innovation subsidies, gas is no longer an option. The construction company can install an air-to-water heat pump with an indoor unit (which operates with outside air) or an outdoor unit, or alternatively a ground collector system with a brine pump. What exactly are the advantages and disadvantages of these options? Which one is more efficient? Is there a risk of ground freezing with the brine system?
Hi,
this:
would be enough for me to dismiss any consideration of a heat pump immediately. The general contractor admits openly that they have no experience (credit to them for at least admitting that!!), so you have a very high chance of ending up with a heating system that either makes noise, doesn’t heat the house properly, or has outrageous electricity costs. Or all of the above!
So you would be a test subject and have to pay for it???
Best regards,
Andreas
this:
expose schrieb:
Hello,
The developer themselves have not had any experience with the pumps so far but would like to install some in the future.
would be enough for me to dismiss any consideration of a heat pump immediately. The general contractor admits openly that they have no experience (credit to them for at least admitting that!!), so you have a very high chance of ending up with a heating system that either makes noise, doesn’t heat the house properly, or has outrageous electricity costs. Or all of the above!
So you would be a test subject and have to pay for it???
Best regards,
Andreas
E
elVincent24 Mar 2016 12:16The main disadvantage of an air source heat pump in most cases is the noise it produces outdoors. Even if you position the outdoor unit so it doesn’t bother you, it can still upset your neighbors.
Regarding ground loop collectors, I see no significant drawbacks other than the space requirements. However, the area needed can become quite large depending on the soil conditions. Different soils generally allow a heat extraction rate of 10–30 W/m² (10 in sandy soil, 30 in clay/loam). With a trench collector, you essentially get the same performance with less effort, but many companies hesitate to take on these projects because the design guidelines are less clear, and no one wants to guarantee something they are not familiar with.
Personally, at the beginning of my heating system selection, I favored the air source heat pump due to its easier installation. However, I ended up choosing a brine-to-water heat pump with a trench collector. In the end, thanks to higher subsidies from BAFA, it wasn’t actually more expensive.
Regarding ground loop collectors, I see no significant drawbacks other than the space requirements. However, the area needed can become quite large depending on the soil conditions. Different soils generally allow a heat extraction rate of 10–30 W/m² (10 in sandy soil, 30 in clay/loam). With a trench collector, you essentially get the same performance with less effort, but many companies hesitate to take on these projects because the design guidelines are less clear, and no one wants to guarantee something they are not familiar with.
Personally, at the beginning of my heating system selection, I favored the air source heat pump due to its easier installation. However, I ended up choosing a brine-to-water heat pump with a trench collector. In the end, thanks to higher subsidies from BAFA, it wasn’t actually more expensive.
B
Bauexperte24 Mar 2016 12:25elVincent schrieb:
The main disadvantage of an air source heat pump in most cases is the noise level outdoors. If only the cheapest offer is accepted: yes. Otherwise, I would really be happy if these “condition descriptions” of a split system could finally be sent where they belong: to the realm of myths. Regards, Bauexperte
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