ᐅ Air source heat pump with fireplace, hydronic stove, domestic hot water heating
Created on: 26 Jul 2009 15:45
A
atelier-ava
I have already read through several forums but haven’t found a satisfactory answer. Hopefully, someone here can help me:
We are planning a new build (single-family house, 130m² (1400 ft²)) and are unsure which heating system to choose. Since we plan to mainly heat the ground floor with a fireplace, our idea was to cover the remaining heating demand with an air-source heat pump (due to lower initial costs compared to other heat pump systems). In any case, we want to be independent of gas or oil! You often read that air-source heat pumps are not necessarily the most efficient heating systems, but in our case, it will mostly be used as a backup heating and for hot water supply—or am I mistaken?
Who has experience with the heating system mentioned above and can recommend an air-source heat pump? Or does anyone have an alternative suggestion for an AFFORDABLE heating system?
Thanks for all the answers!
We are planning a new build (single-family house, 130m² (1400 ft²)) and are unsure which heating system to choose. Since we plan to mainly heat the ground floor with a fireplace, our idea was to cover the remaining heating demand with an air-source heat pump (due to lower initial costs compared to other heat pump systems). In any case, we want to be independent of gas or oil! You often read that air-source heat pumps are not necessarily the most efficient heating systems, but in our case, it will mostly be used as a backup heating and for hot water supply—or am I mistaken?
Who has experience with the heating system mentioned above and can recommend an air-source heat pump? Or does anyone have an alternative suggestion for an AFFORDABLE heating system?
Thanks for all the answers!
I
innovision25 Sep 2009 08:03When Does an Investment with Additional Costs of Around €10,000 Pay Off?
In my opinion/experience, many owners of air-to-water heat pumps had to use additional heating with electricity during last winter’s extreme cold. The first complaints appeared as early as February 2009 when the additional bills for 2008 arrived. More will follow since, as is well known, January to March 2009 were even colder.
However, it is also true that if the house is very well insulated (as required by the 2009 Energy Saving Ordinance / thermal insulation regulations for new buildings), heating costs are very low – for example, €50 (about $55) per month, regardless of whether heating is by gas, electricity, or wood. Then I would suggest calculating: if heating costs rise by more than 100% – for example, €100 (about $110) monthly in a new building, or for an older house from €240 (about $265) to €500 (about $550) per month – this could lead to a wave of personal bankruptcies among owners of houses older than 20 years.
So the difference in operating costs between electric heat (air-to-water heat pump) and gas heating is about €30 (about $33) per month, which equals €360 (about $395) per year, or roughly €10,000 (about $11,000) over 30 years. At that point, the investment pays off. I wouldn’t do it myself because I can’t make it financially add up today.
BUT including underfloor heating in the build (and maybe using it) and then possibly converting after 10 years when the additional cost is minimal (a geothermal borehole also costs about €10,000 (about $11,000) more compared to a gas system) could be a good option.
PS: This is without maintenance and filter replacement costs... I am currently replacing a 30-year-old gas heating system myself...
But I have never seen an electrical appliance or pump running 24/7 in a house be older than 10 years...
In my opinion/experience, many owners of air-to-water heat pumps had to use additional heating with electricity during last winter’s extreme cold. The first complaints appeared as early as February 2009 when the additional bills for 2008 arrived. More will follow since, as is well known, January to March 2009 were even colder.
However, it is also true that if the house is very well insulated (as required by the 2009 Energy Saving Ordinance / thermal insulation regulations for new buildings), heating costs are very low – for example, €50 (about $55) per month, regardless of whether heating is by gas, electricity, or wood. Then I would suggest calculating: if heating costs rise by more than 100% – for example, €100 (about $110) monthly in a new building, or for an older house from €240 (about $265) to €500 (about $550) per month – this could lead to a wave of personal bankruptcies among owners of houses older than 20 years.
So the difference in operating costs between electric heat (air-to-water heat pump) and gas heating is about €30 (about $33) per month, which equals €360 (about $395) per year, or roughly €10,000 (about $11,000) over 30 years. At that point, the investment pays off. I wouldn’t do it myself because I can’t make it financially add up today.
BUT including underfloor heating in the build (and maybe using it) and then possibly converting after 10 years when the additional cost is minimal (a geothermal borehole also costs about €10,000 (about $11,000) more compared to a gas system) could be a good option.
PS: This is without maintenance and filter replacement costs... I am currently replacing a 30-year-old gas heating system myself...
But I have never seen an electrical appliance or pump running 24/7 in a house be older than 10 years...
Atelier-ava schrieb:
I’ve read through numerous forums but haven’t found a satisfactory answer. I hope someone here can help:
We are planning a new build (single-family house, 130m² (about 1400 sq ft)) and are unsure which heating system to choose. Since we intend to mainly heat the ground floor with a fireplace, our idea was to cover the remaining heating demand with an air-source heat pump (due to lower initial costs compared to other heat pump systems). In any case, we want to be independent of gas or oil! You often read that air-source heat pumps are not necessarily the most efficient heating systems, but in our case it would mainly be for “supplemental heating” and domestic hot water supply – or am I mistaken?!
Who has experience with the above heating system and could possibly recommend an air-source heat pump? Or who has an alternative suggestion for an AFFORDABLE heating system?
Thanks for all answers!
@innovision
Why should anyone start crying about this?
Air-source heat pumps are always designed with an electric backup heater.
It is well known that this type of heat pump does not achieve high annual performance factors.
Here, however, there is a fireplace available as mentioned in the question.
A building constructed according to the 2009 Energy Saving Ordinance is by no means "super insulated."
It is no coincidence that the 2012 Energy Saving Ordinance tightened requirements by about 30%.
The rules for energy-efficient buildings still apply.
- for example, €50 heating costs – no matter what fuel is used, whether gas, electricity, or wood
Energy carriers do not have the same costs or rate of increase by far.
So the difference in operating electricity costs (air-to-water heat pump vs. gas) is about €30 per month = €360 per year = approximately €10,000 over 30 years. Then the investment pays off.
And who cares, in 30 years nobody will be able to afford gas anymore?
Why should anyone start crying about this?
Air-source heat pumps are always designed with an electric backup heater.
It is well known that this type of heat pump does not achieve high annual performance factors.
Here, however, there is a fireplace available as mentioned in the question.
A building constructed according to the 2009 Energy Saving Ordinance is by no means "super insulated."
It is no coincidence that the 2012 Energy Saving Ordinance tightened requirements by about 30%.
The rules for energy-efficient buildings still apply.
- for example, €50 heating costs – no matter what fuel is used, whether gas, electricity, or wood
Energy carriers do not have the same costs or rate of increase by far.
So the difference in operating electricity costs (air-to-water heat pump vs. gas) is about €30 per month = €360 per year = approximately €10,000 over 30 years. Then the investment pays off.
And who cares, in 30 years nobody will be able to afford gas anymore?
Atelier-ava schrieb:
... Since we plan to heat primarily with a fireplace on the ground floor at least, our idea was to cover the remaining heating demand with an air-source heat pump (due to lower initial costs compared to other heat pump systems). A fireplace is hardly suitable for continuous heating loads. It is no coincidence that the KfW rejects recognition of partial heating load coverage. In my opinion, this is because continuous and sustainable use is not achievable.
Atelier-ava schrieb:
You often read that air-source heat pumps are not necessarily the most efficient heating systems, but in our case it is mainly used for "top-up heating" and hot water supply – or am I mistaken?! Air-source heat pumps are less energy-efficient compared to ground-source or water-source heat pumps. However, they come with significantly lower initial investment costs. The system that makes economic sense for a specific situation can be identified through a cost-effectiveness comparison. Heating and domestic hot water preparation should be considered together rather than separately.
Hot water preparation lowers the seasonal performance factor of the heat pump. Depending on the share of energy used for hot water relative to heating energy demand, this plays a significant role.
In several economic comparisons I conducted for single-family homes, air-source heat pumps and gas condensing boilers finished in a "neck and neck" race.
To operate heat pumps efficiently, low supply temperatures for the heat distribution system are required, meaning underfloor heating or wall heating are the only suitable options. However, this requires heating the entire house continuously. Flexible heating operation is no longer possible then. Specifically for the builder: warm feet in the bathroom will not be guaranteed!
Air-source heat pumps have further specific characteristics that must be taken into account. Nevertheless, depending on the climate zone, user behavior, and the building’s insulation standard, they can be a viable alternative.
Best regards
Depending on the design, only in a passive house.
Because here, the air-source heat pump is only an "emergency heater."
Air-source heat pumps do not have such a poor BAFA funding rating without reason.
Or sophisticated combinations of biomass / exhaust air heat pump / solar thermal systems. See Institut Wohnen und Umwelt.
Because here, the air-source heat pump is only an "emergency heater."
Air-source heat pumps do not have such a poor BAFA funding rating without reason.
Or sophisticated combinations of biomass / exhaust air heat pump / solar thermal systems. See Institut Wohnen und Umwelt.
How do I determine the annual performance factor? I am considering a ground-to-water heat pump from Alpha Innotec with a COP value of 3.5. The system seems suitable for our construction project, but I am wondering: is this a good ground-to-water heat pump? Are there better options? Is a COP of 3.5 acceptable?
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