ᐅ New Single-Family Home Construction | Choosing the "Right" Heating System
Created on: 14 Jun 2017 07:19
Z
zehn0813
Good morning!
Clearly, there is no perfect heating system. But which one could be the right choice for us?
In connection with the construction of a new single-family house with 170m² (1830 sq ft) of living space, 1.5 stories, the initial requirement given to the architect was that it should meet the KfW55 standard to qualify for subsidies. At the same time, we were very interested in the ground-source heat pump – even though it is expensive. Furthermore, a controlled mechanical ventilation system was a must, and the photovoltaic system should at least be prepared.
After digging deeper into the topic, it is now clear that the KfW55 standard will not be achieved. We just miss the target value for the average transmission heat loss.
With 8cm (3 inches) more insulation in the exterior walls, we would meet the standard, but this would reduce the living space since the building footprint is almost fully used. According to our architect (who is also the energy consultant), the additional costs would be around €2,000, but the annual heating savings would be only about €30.
Moreover, from a financing perspective, adhering to the KfW55 standard no longer makes sense for us.
Nonetheless, we initially continued planning to install a ground-source heat pump. We have always felt uneasy about an air-source heat pump, and with a gas condensing boiler, we were somewhat bothered by the solar thermal system on the roof, which is required for the renewable share under the KfW55 standard.
By now, we have the thermal insulation verification of the building and the heating load (~7.5 kW) is known. We also received initial offers for both a ground-source heat pump and an air-source heat pump. And now, we are reconsidering again!
I’ll try to summarize the comparison briefly:
Ground-source heat pump: ~€18,000 (including multifunction storage tank)
+ Deep drilling: ~€10,000
- Subsidies (BAFA and NRW Progress): ~€6,000
Total: ~€22,000
Air-source heat pump: ~€16,500 (including multifunction storage tank)
We do not have an offer yet for a gas condensing boiler including a suitable storage tank, but roughly it seems to be about €10,000 (including storage and installation). Along with the costs for the chimney and gas connection, we would at most break even compared to the air-source heat pump.
Since we will no longer meet the KfW55 standard but only need to comply with the Energy Saving Ordinance (EnEV), we do not require solar thermal anymore. The building envelope, however, is close to KfW55 standard – so it is very tight.
Setting aside the intangible value and ecological considerations, the additional costs of the ground-source heat pump somehow no longer make sense! This brings the gas condensing boiler back into play, especially since the heating load is very low due to the building envelope.
We are really torn and would appreciate any feedback on our perspective.
Best regards,
zehn0813
Clearly, there is no perfect heating system. But which one could be the right choice for us?
In connection with the construction of a new single-family house with 170m² (1830 sq ft) of living space, 1.5 stories, the initial requirement given to the architect was that it should meet the KfW55 standard to qualify for subsidies. At the same time, we were very interested in the ground-source heat pump – even though it is expensive. Furthermore, a controlled mechanical ventilation system was a must, and the photovoltaic system should at least be prepared.
After digging deeper into the topic, it is now clear that the KfW55 standard will not be achieved. We just miss the target value for the average transmission heat loss.
With 8cm (3 inches) more insulation in the exterior walls, we would meet the standard, but this would reduce the living space since the building footprint is almost fully used. According to our architect (who is also the energy consultant), the additional costs would be around €2,000, but the annual heating savings would be only about €30.
Moreover, from a financing perspective, adhering to the KfW55 standard no longer makes sense for us.
Nonetheless, we initially continued planning to install a ground-source heat pump. We have always felt uneasy about an air-source heat pump, and with a gas condensing boiler, we were somewhat bothered by the solar thermal system on the roof, which is required for the renewable share under the KfW55 standard.
By now, we have the thermal insulation verification of the building and the heating load (~7.5 kW) is known. We also received initial offers for both a ground-source heat pump and an air-source heat pump. And now, we are reconsidering again!
I’ll try to summarize the comparison briefly:
Ground-source heat pump: ~€18,000 (including multifunction storage tank)
+ Deep drilling: ~€10,000
- Subsidies (BAFA and NRW Progress): ~€6,000
Total: ~€22,000
Air-source heat pump: ~€16,500 (including multifunction storage tank)
We do not have an offer yet for a gas condensing boiler including a suitable storage tank, but roughly it seems to be about €10,000 (including storage and installation). Along with the costs for the chimney and gas connection, we would at most break even compared to the air-source heat pump.
Since we will no longer meet the KfW55 standard but only need to comply with the Energy Saving Ordinance (EnEV), we do not require solar thermal anymore. The building envelope, however, is close to KfW55 standard – so it is very tight.
Setting aside the intangible value and ecological considerations, the additional costs of the ground-source heat pump somehow no longer make sense! This brings the gas condensing boiler back into play, especially since the heating load is very low due to the building envelope.
We are really torn and would appreciate any feedback on our perspective.
Best regards,
zehn0813
I roughly calculate it like this. Gas heating including solar and connection costs about 6000, compared to air-to-water heat pumps. I’m not interested in KfW subsidies.
Operating costs estimated by the building contractor: Gas 1000 per year. Electricity for the two of us is currently 850 per year.
1850 plus 50 for the chimney sweep equals 1900.
Air-to-water heat pump: gas zero, chimney sweep zero. Electricity, yes, in a cold winter about 2400 per year; in a mild winter, only 1800. On average over the years, the air-to-water heat pump is not cheaper to operate than gas, only it is more expensive to purchase. Both systems need maintenance because it wouldn’t be fair to say one breaks down and the other doesn’t. I’m leaving that aside.
If I could reduce the compressor’s electricity consumption by about 400 per year with photovoltaic panels, which would be possible, it would look better. Unfortunately, the photovoltaic system would also require an additional investment of several thousand. So, all in all, nothing gained but expenses. Karsten
Operating costs estimated by the building contractor: Gas 1000 per year. Electricity for the two of us is currently 850 per year.
1850 plus 50 for the chimney sweep equals 1900.
Air-to-water heat pump: gas zero, chimney sweep zero. Electricity, yes, in a cold winter about 2400 per year; in a mild winter, only 1800. On average over the years, the air-to-water heat pump is not cheaper to operate than gas, only it is more expensive to purchase. Both systems need maintenance because it wouldn’t be fair to say one breaks down and the other doesn’t. I’m leaving that aside.
If I could reduce the compressor’s electricity consumption by about 400 per year with photovoltaic panels, which would be possible, it would look better. Unfortunately, the photovoltaic system would also require an additional investment of several thousand. So, all in all, nothing gained but expenses. Karsten
Where do you always get these absurd numbers from? €2400 for electricity is nonsense. We already understand that you prefer gas, but please drop the dramatics.
Drilling over 100 meters requires an additional approval step, yes. That means two more forms for the drilling company to submit. No big deal according to our provider; it’s just treated as an imaginary limit online.
Having only one borehole is more effective and efficient at the same time—I would get some more advice on that.
I calculated BAFA subsidies at €5000; most heat pumps are now SG-ready, and there is also a €500 bonus for load management.
Without heating load calculations and knowing the expected heat extraction capacity at the location, the target depth is just a guess.
We were offered €60 per meter plus €300 for the container. Including house entry, basically ready to connect for the heating engineer.
Drilling over 100 meters requires an additional approval step, yes. That means two more forms for the drilling company to submit. No big deal according to our provider; it’s just treated as an imaginary limit online.
Having only one borehole is more effective and efficient at the same time—I would get some more advice on that.
I calculated BAFA subsidies at €5000; most heat pumps are now SG-ready, and there is also a €500 bonus for load management.
Without heating load calculations and knowing the expected heat extraction capacity at the location, the target depth is just a guess.
We were offered €60 per meter plus €300 for the container. Including house entry, basically ready to connect for the heating engineer.
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