ᐅ Which heating system? Air source heat pump / gas / geothermal heating
Created on: 26 Mar 2015 19:57
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Nina132
Hello everyone,
we are building a single-family house with 155m2 (1,670 sq ft) and want to try to meet KfW55 standards (at least that is what is stated in the contract). Underfloor heating is mandatory. We are working with an architect who also acts as the general contractor, so the house will be delivered turnkey.
The challenges are as follows:
1. North-facing slope – no opportunity for solar panels
2. Sloped site – the ground floor (GF) will be partially built into the hillside at the back. The bedrooms will be on the GF, while the living area is on the upper floor (UF) with a level exit “onto” the slope. By embedding the GF on one side, we can have a reasonably flat garden at the top.
3. There are currently just two of us, but a child is planned in about five years
4. We want a large bathtub and will therefore need a lot of hot water
5. I like to ventilate frequently and thoroughly
6. The utility room is on the GF along with the bedrooms. Could there be noise issues?
Now about the heating decision.
Originally, especially my partner wanted a ground source heat pump. That is probably the best option in terms of quality and ecology, but it is very expensive.
An air source heat pump is of course an alternative, but I’m concerned about electricity costs in winter because I suspect that, especially the GF, will cool down quickly due to the hillside situation.
Our architect recommends a gas condensing boiler, saying this is standard for 80% of new builds. We actually wanted to move away from gas and oil, but electricity also involves fossil fuels – at least indirectly. Of course, this would probably rule out KfW55 compliance, but I think KfW70 would also be acceptable.
What are your thoughts?
we are building a single-family house with 155m2 (1,670 sq ft) and want to try to meet KfW55 standards (at least that is what is stated in the contract). Underfloor heating is mandatory. We are working with an architect who also acts as the general contractor, so the house will be delivered turnkey.
The challenges are as follows:
1. North-facing slope – no opportunity for solar panels
2. Sloped site – the ground floor (GF) will be partially built into the hillside at the back. The bedrooms will be on the GF, while the living area is on the upper floor (UF) with a level exit “onto” the slope. By embedding the GF on one side, we can have a reasonably flat garden at the top.
3. There are currently just two of us, but a child is planned in about five years
4. We want a large bathtub and will therefore need a lot of hot water
5. I like to ventilate frequently and thoroughly
6. The utility room is on the GF along with the bedrooms. Could there be noise issues?
Now about the heating decision.
Originally, especially my partner wanted a ground source heat pump. That is probably the best option in terms of quality and ecology, but it is very expensive.
An air source heat pump is of course an alternative, but I’m concerned about electricity costs in winter because I suspect that, especially the GF, will cool down quickly due to the hillside situation.
Our architect recommends a gas condensing boiler, saying this is standard for 80% of new builds. We actually wanted to move away from gas and oil, but electricity also involves fossil fuels – at least indirectly. Of course, this would probably rule out KfW55 compliance, but I think KfW70 would also be acceptable.
What are your thoughts?
One important aspect to always keep in mind when calculating heating costs is the ongoing expenses and hidden initial costs.
For example, a gas boiler or pellet system requires a chimney flue costing around 2,000 euros, which is not needed for a heat pump. With pellets, there are also annual maintenance fees of about 150 euros. Additionally, both pellet and gas systems require electricity to run the circulation pumps. For pellets, the space for storing the pellets should also be considered part of the initial investment.
With a heat pump, the electricity consumption is fully accounted for in the annual performance factor, and if the pump uses less than 3 kg (6.6 pounds) of refrigerant, no maintenance is usually required.
We initially considered pellets or a ground source heat pump... Gas was not an option for us since we don’t have a connection, and we didn’t want a tank. We ultimately decided on an air-source heat pump, which costs about 10,000 euros less than the other two options. Even if we end up with around 300 euros more in electricity costs per year, in our view, it’s not worth investing in ground source heat.
Addendum: By the way, gas burns the cleanest among the fuels, producing the least CO2 and fine dust emissions. (Pellets are actually worse, but are portrayed as "green" because trees can regrow.)
For example, a gas boiler or pellet system requires a chimney flue costing around 2,000 euros, which is not needed for a heat pump. With pellets, there are also annual maintenance fees of about 150 euros. Additionally, both pellet and gas systems require electricity to run the circulation pumps. For pellets, the space for storing the pellets should also be considered part of the initial investment.
With a heat pump, the electricity consumption is fully accounted for in the annual performance factor, and if the pump uses less than 3 kg (6.6 pounds) of refrigerant, no maintenance is usually required.
We initially considered pellets or a ground source heat pump... Gas was not an option for us since we don’t have a connection, and we didn’t want a tank. We ultimately decided on an air-source heat pump, which costs about 10,000 euros less than the other two options. Even if we end up with around 300 euros more in electricity costs per year, in our view, it’s not worth investing in ground source heat.
Addendum: By the way, gas burns the cleanest among the fuels, producing the least CO2 and fine dust emissions. (Pellets are actually worse, but are portrayed as "green" because trees can regrow.)
There is a gas connection available at the street. At least during the summer, I won’t be able to change my ventilation habits. We have cats, cat food smells, and I am allergic to cooking fumes, so I like to open the window immediately. I want to live in my house the way I want and am also willing to pay more for that.
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nordanney27 Mar 2015 10:30Nina132 schrieb:
There is a gas connection available at the street.
At least in summer, I won’t be able to change my ventilation habits. We have cats, cat food smells, and I am allergic to cooking fumes, so I like to open the window immediately. I want to live in my house the way I want and am also willing to pay more for that. How about a controlled mechanical ventilation system? The only way to get more fresh air would be to keep windows and doors open constantly – which can get quite cold in winter.
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