Dear forum,
After browsing here for a while, I’m even more impressed by the amount of expert help and advice available.
That’s why I hope some of you can evaluate our current house planning status, as I’ve already heard very different opinions from various sources.
We are planning a Mediterranean-style house with about 140 m² (1,507 sq ft) of living space without a basement. It would be built by the construction company as follows: exterior walls made of Poroton masonry with a thickness of 36.5 cm (14 inches), plastered in two layers. The heating system would be a gas condensing boiler combined with a solar panel system of about 5 m² (54 sq ft). The entire building will be heated with underfloor heating. Since we also own a piece of forest, we would additionally use a tiled stove for supplementary heating, which, however, is not connected to the main heating system.
Without taking the tiled stove into account, the house meets the KFW 100 standard.
We are now unsure whether the additional investment and consequently higher interest rates will pay off in the long run to upgrade the house to meet the KFW 70 standard.
What do you think?
After browsing here for a while, I’m even more impressed by the amount of expert help and advice available.
That’s why I hope some of you can evaluate our current house planning status, as I’ve already heard very different opinions from various sources.
We are planning a Mediterranean-style house with about 140 m² (1,507 sq ft) of living space without a basement. It would be built by the construction company as follows: exterior walls made of Poroton masonry with a thickness of 36.5 cm (14 inches), plastered in two layers. The heating system would be a gas condensing boiler combined with a solar panel system of about 5 m² (54 sq ft). The entire building will be heated with underfloor heating. Since we also own a piece of forest, we would additionally use a tiled stove for supplementary heating, which, however, is not connected to the main heating system.
Without taking the tiled stove into account, the house meets the KFW 100 standard.
We are now unsure whether the additional investment and consequently higher interest rates will pay off in the long run to upgrade the house to meet the KFW 70 standard.
What do you think?
Doug schrieb:
.... The heating system would be a gas condensing boiler combined with a solar thermal system of about 5 m² (54 ft²). Solar thermal systems are usually not cost-effective in single-family homes. Doug schrieb:
.... Since we also own a piece of forest, we would additionally heat with a tiled stove, which is not connected to the main heating system. At least it’s a tiled stove and not a wood stove. 🙂 Doug schrieb:
.... We are not really sure if the additional investment and thus the higher interest rates will pay off in the long term to bring the house up to the KfW70 standard. You can only be sure after an exact basic assessment/calculation, meaning the actual demand (capacity, energy) for heating and domestic hot water must be known. Anything else would be guesswork, assumptions, or a look into a cloudy crystal ball. 😉 With a conventional heat generator, consumption is higher than demand, so in this case it would probably turn out more favorable. With a heat pump, consumption is lower than demand, so only a fraction of the investment is actually effective. In other words, the economic requirements for insulation are lower here.
For gas heating, it’s better to insulate well and skip the solar thermal system. For a heat pump, insulate more sparingly and alternatively install a photovoltaic system on the roof. Sometimes this can cover heating and hot water costs completely or finance these expenses through the capital cost of the photovoltaic system.
Saving energy costs usually starts with selecting the right plot of land, continues with the building design, and ends with proper sizing and selection of the system. 😉
Best regards
Thank you for the quick and informative response!
I would also prefer a ground source heat pump and to retrofit photovoltaic systems later, but due to the rocky ground, the additional costs for drilling or ground loop installation are too high for me. Also, there is not enough long-term experience with this option for me. An air source heat pump is currently not an option either. On one hand, I think the noise would bother me because of the lack of a basement, and on the other hand, the efficiency is too low for me, especially if electricity prices were to rise sharply.
The company that would build the house for us on a turnkey basis has already estimated the heating costs at approximately 1400€ per year, without taking the tiled stove into account.
I would also prefer a ground source heat pump and to retrofit photovoltaic systems later, but due to the rocky ground, the additional costs for drilling or ground loop installation are too high for me. Also, there is not enough long-term experience with this option for me. An air source heat pump is currently not an option either. On one hand, I think the noise would bother me because of the lack of a basement, and on the other hand, the efficiency is too low for me, especially if electricity prices were to rise sharply.
The company that would build the house for us on a turnkey basis has already estimated the heating costs at approximately 1400€ per year, without taking the tiled stove into account.
Doug schrieb:
..... in case electricity prices suddenly increase sharply. The specific costs of all energy sources will gradually rise. Some more in one year, others in the following year.Doug schrieb:
..... The company that would build the house as a turnkey project has already estimated heating costs at about 1400€ per year, excluding the tiled stove. Well, estimating is tricky. Many have significantly underestimated. I wouldn’t rely on such estimates for a major investment decision.Best regards
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