Hello,
Last week, we visited the planner for the first time, who is now working on the initial design of our new home. It will be about 140 sqm (1,507 sq ft), one and a half stories, and without a basement. We will be living in it as a family of four. For some time now, I have been thinking about the heating system.
I have spent hours researching online trying to get a clear picture. Here is what I have gathered so far:
Groundwater heat pump -> I initially liked this idea, but since we live near an open-pit mine, I can’t predict how the groundwater in the area might change.
Air source heat pump -> I’m not convinced… low efficiency in cold winters and also disturbing noise.
Ground source heat pump / collector -> One of my favorites, but not possible due to our property.
Ground source heat pump / borehole -> My current favorite. Downside: most expensive to install (unexpected costs with drilling?).
Oil heating -> I rule this out, as it takes up too much space that I’d rather use otherwise.
Pellet heating -> Also ruled out, for the same reason: too much space required.
When I told the planner about my current favorite—the ground source heat pump with a borehole—she introduced the topic of a gas heating system. Heat pumps can cost up to 25,000 euros (about 27,000 USD), and they are no longer as cost-effective... Houses today are insulated so well that gas is not as expensive for a single-family home. Her opinion was that the higher investment in heat pumps would never pay off. Also, the gas connection is already available on our street...
On the other hand, I have read that a gas condensing boiler alone might not be sufficient, as a certain energy standard for new buildings must be met. Therefore, only a gas condensing boiler combined with solar thermal (for hot water) would be feasible and probably sensible. The problem here is the orientation of the house/roof—it does not allow for a south-facing installation of solar collectors. Only east or west-facing options are possible, which are quite ineffective in this context.
What do you think? Do you believe a ground source heat pump would be more cost-effective than a gas condensing boiler? Or does it not make much difference in a new build, and the higher investment is not worth it? Or maybe it is worth it precisely because the solar thermal system cannot be fully utilized?
Estimated costs:
Ground source heat pump with borehole: 25,000 euros (about 27,000 USD)
Gas condensing boiler with solar thermal: 12,000 euros (about 13,000 USD)
New build location near Cottbus (deep eastern region).
Last week, we visited the planner for the first time, who is now working on the initial design of our new home. It will be about 140 sqm (1,507 sq ft), one and a half stories, and without a basement. We will be living in it as a family of four. For some time now, I have been thinking about the heating system.
I have spent hours researching online trying to get a clear picture. Here is what I have gathered so far:
Groundwater heat pump -> I initially liked this idea, but since we live near an open-pit mine, I can’t predict how the groundwater in the area might change.
Air source heat pump -> I’m not convinced… low efficiency in cold winters and also disturbing noise.
Ground source heat pump / collector -> One of my favorites, but not possible due to our property.
Ground source heat pump / borehole -> My current favorite. Downside: most expensive to install (unexpected costs with drilling?).
Oil heating -> I rule this out, as it takes up too much space that I’d rather use otherwise.
Pellet heating -> Also ruled out, for the same reason: too much space required.
When I told the planner about my current favorite—the ground source heat pump with a borehole—she introduced the topic of a gas heating system. Heat pumps can cost up to 25,000 euros (about 27,000 USD), and they are no longer as cost-effective... Houses today are insulated so well that gas is not as expensive for a single-family home. Her opinion was that the higher investment in heat pumps would never pay off. Also, the gas connection is already available on our street...
On the other hand, I have read that a gas condensing boiler alone might not be sufficient, as a certain energy standard for new buildings must be met. Therefore, only a gas condensing boiler combined with solar thermal (for hot water) would be feasible and probably sensible. The problem here is the orientation of the house/roof—it does not allow for a south-facing installation of solar collectors. Only east or west-facing options are possible, which are quite ineffective in this context.
What do you think? Do you believe a ground source heat pump would be more cost-effective than a gas condensing boiler? Or does it not make much difference in a new build, and the higher investment is not worth it? Or maybe it is worth it precisely because the solar thermal system cannot be fully utilized?
Estimated costs:
Ground source heat pump with borehole: 25,000 euros (about 27,000 USD)
Gas condensing boiler with solar thermal: 12,000 euros (about 13,000 USD)
New build location near Cottbus (deep eastern region).
For us, the geothermal system including the drilling also cost around 15,000 euros.
The planning was estimated at 13,000 to 14,000, but the drilling ended up being a bit more expensive (1,500 euros).
With this price, the decision was very easy for us.
See the information from @klblb – adding your solar thermal system, you will likely reach similar price ranges.
It’s good that you are gathering information about the different options. It would be sensible to get quotes for your two favorites.
Make sure to also check how geothermal energy is regulated and whether it is practical in your building region. Cottbus belonged to the "brown coal heartland" of the former East Germany for decades, and to my knowledge, the area was still mined by MiBrAG during the unified German period. You don’t want to face any unexpected "issues" there.
The planning was estimated at 13,000 to 14,000, but the drilling ended up being a bit more expensive (1,500 euros).
With this price, the decision was very easy for us.
See the information from @klblb – adding your solar thermal system, you will likely reach similar price ranges.
It’s good that you are gathering information about the different options. It would be sensible to get quotes for your two favorites.
Make sure to also check how geothermal energy is regulated and whether it is practical in your building region. Cottbus belonged to the "brown coal heartland" of the former East Germany for decades, and to my knowledge, the area was still mined by MiBrAG during the unified German period. You don’t want to face any unexpected "issues" there.
Basti2709 schrieb:
What size do the collectors need to be? I read something about twice the size of the heated area... 140 sqm x 2 = 280 sqm (3006 sqft) collector area? On one side, maybe 140 sqm (1507 sqft) would fit with the required spacing... I actually didn’t want to run it over the water pipe itself, since that is about 2.00 meters (6.6 ft) deep.The general rule of thumb is double the square meters of the house as a rough sizing, without detailed calculations, where the HVAC installer sizes it to definitely be sufficient. A heat loss calculation and detailed planning are necessary to determine the actual demand and the correct extraction rate.
That makes sense in your case because the space is tight.
This forum can’t assist with the planning, but there is another forum specializing in horizontal ground collectors where knowledgeable people have done a lot of work...
T
toxicmolotof3 Dec 2014 14:53I will also transfer the mentioned 40,000 euros to our heating contractor, but that includes underfloor heating and the complete sanitary installation.
If you always follow the "better to overestimate" approach, a house that should cost around 300,000 euros might end up costing 400,000 euros.
It’s better to involve someone who has experience with this kind of project—whether it’s an architect, general contractor, construction manager, sales representative, or anyone else. When it comes to heating, a conversation with a heating installer who works with both systems might be enough. They usually have a good understanding of the local market, including additional costs like gas connection or drilling, which can provide a useful initial orientation.
If you always follow the "better to overestimate" approach, a house that should cost around 300,000 euros might end up costing 400,000 euros.
It’s better to involve someone who has experience with this kind of project—whether it’s an architect, general contractor, construction manager, sales representative, or anyone else. When it comes to heating, a conversation with a heating installer who works with both systems might be enough. They usually have a good understanding of the local market, including additional costs like gas connection or drilling, which can provide a useful initial orientation.
Doc.Schnaggls schrieb:
Hello,
have you already included the gas connection in the EUR 12,000.00 for the gas condensing boiler with solar thermal system?
A few thousand euros more there, and suddenly you might not be far from a heat pump...
How about an air-to-water heat pump combined with a photovoltaic system on the roof?
With proper sizing, you could then heat and provide hot water at virtually no cost in the future.
Regards,
DirkUnfortunately, heating at no cost does not work for us here in Upper Franconia with this setup, because in winter (currently almost two weeks without direct sunlight, 0 degrees Celsius (32°F) or below) the photovoltaic system produces no electricity for the heat pump – the same at night, so roughly from 4 p.m. to 9 a.m. in winter. And precisely when I need electricity from the photovoltaic system for the heat pump, it does not supply any.
And for hot water preparation in summer, only a small amount of electricity is needed anyway.
For your 140 m² (1,507 ft²), I would choose gas (but without solar) – not KfW 70 standard, but why not –, an air-to-water heat pump (which climate region?), or a ground-source heat pump. And for the energy demand of a new 140 m² (1,507 ft²) house, drilling costs should not be that high either.
Best regards
B
Bauherren20144 Dec 2014 15:34I agree with the statement regarding heating load calculation (HLB) and planning from @oleda222, although I would generalize it a bit further.
Have a heating load calculation done to determine your needs and consult with a specialist. Then you can make the final decision on the heating technology. In the end, they will also be able to tell you whether a trench collector or surface collector is suitable for you or not.
Just for comparison: We initially also wanted a ground source heat pump with drilling. Therefore, we commissioned a hydrogeological report. It turned out that, because of our clay soil, we would need a total of 3 boreholes of 100 meters (330 feet) each to make the system efficient. The drilling alone would have cost us nearly 20,000 euros. In the end, we would also have almost reached 40,000 euros. While this is not necessarily the typical case, as you can see, anything is possible. In the end, the report cost us some money, but it made the decision much easier for us to opt against drilling.
Have a heating load calculation done to determine your needs and consult with a specialist. Then you can make the final decision on the heating technology. In the end, they will also be able to tell you whether a trench collector or surface collector is suitable for you or not.
Basti2709 schrieb:
Also, because I have already read in other forums about ground source heat pumps with ground probes costing 40,000 euros...
toxicmolotow schrieb:
I would also pay the mentioned 40,000 euros to our heating installer. But that includes underfloor heating and complete sanitary installation.
Just for comparison: We initially also wanted a ground source heat pump with drilling. Therefore, we commissioned a hydrogeological report. It turned out that, because of our clay soil, we would need a total of 3 boreholes of 100 meters (330 feet) each to make the system efficient. The drilling alone would have cost us nearly 20,000 euros. In the end, we would also have almost reached 40,000 euros. While this is not necessarily the typical case, as you can see, anything is possible. In the end, the report cost us some money, but it made the decision much easier for us to opt against drilling.
Bauherren2014 schrieb:
Have a heat load calculation done to determine your requirements and consult with a professional. Then you can proceed to make the final decision about the heating technology. The expert will also be able to tell you whether a trench collector or ground collector system is suitable for you or not.I doubt that a "professional" would recommend a trench collector. It is still not widely adopted by specialist companies in Germany...
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