Hi,
I would like to gather a few more opinions on the pros and cons of solar thermal collectors supporting heating in combination with a gas condensing boiler.
Some background information:
The house faces south and is located in the mild and sunny Rhine valley with no shading, approximately 160 sqm (1,722 sq ft) of living space. No underfloor heating is planned in the living areas. The walls are made of 24 cm (9.5 inches) Ytong blocks without insulation, but very good (new) windows and doors will be installed. Roof insulation will also be added.
The (NOT independent) energy consultant advised against it. His reasoning: when heating is needed, there is usually no sun or not enough sunlight—his opinion is that the maximum annual savings (under ideal year-round weather conditions, etc.) would be about 80–100 € (~$85–$105), which does not justify the investment costs. He suggests only supporting domestic hot water.
Sanitary company A had the opposite view. Heating support is the only way to go; the investment cost would be moderate since you can also get funding from BAFA. Their plan includes a buffer tank of around 500–600 liters (132–158 gallons) and domestic hot water on a flow-through system.
Sanitary company B said roughly the same as the energy consultant and stated that at least an 800-liter (211 gallons) tank would be necessary (which is very expensive) and recommended only domestic hot water support.
Sanitary company C could not or would not give a clear recommendation. They warned about the costs of heating support (around 10,000 €), said they had installed it in their own house and generally recommend it, but ultimately suggested that only domestic hot water support might be more reasonable.
The detailed offers with cost breakdowns will be sent to me by the companies in the next few days.
So, what do you think?
Regards
I would like to gather a few more opinions on the pros and cons of solar thermal collectors supporting heating in combination with a gas condensing boiler.
Some background information:
The house faces south and is located in the mild and sunny Rhine valley with no shading, approximately 160 sqm (1,722 sq ft) of living space. No underfloor heating is planned in the living areas. The walls are made of 24 cm (9.5 inches) Ytong blocks without insulation, but very good (new) windows and doors will be installed. Roof insulation will also be added.
The (NOT independent) energy consultant advised against it. His reasoning: when heating is needed, there is usually no sun or not enough sunlight—his opinion is that the maximum annual savings (under ideal year-round weather conditions, etc.) would be about 80–100 € (~$85–$105), which does not justify the investment costs. He suggests only supporting domestic hot water.
Sanitary company A had the opposite view. Heating support is the only way to go; the investment cost would be moderate since you can also get funding from BAFA. Their plan includes a buffer tank of around 500–600 liters (132–158 gallons) and domestic hot water on a flow-through system.
Sanitary company B said roughly the same as the energy consultant and stated that at least an 800-liter (211 gallons) tank would be necessary (which is very expensive) and recommended only domestic hot water support.
Sanitary company C could not or would not give a clear recommendation. They warned about the costs of heating support (around 10,000 €), said they had installed it in their own house and generally recommend it, but ultimately suggested that only domestic hot water support might be more reasonable.
The detailed offers with cost breakdowns will be sent to me by the companies in the next few days.
So, what do you think?
Regards
We decided against the heating support system. I see the same reason for this as the energy consultant you mentioned. In winter, when you need it, it gets dark early and light late. Often it is cloudy as well. If every winter in the Rhine-Main area were like this one, it might be worth considering, but the investment seems disproportionate for our single-family home.
I’m not exactly sure how large the 800 L (210 gallon) tank is, but there is definitely enough space available (not a new build but an existing property). The problem would rather be getting the unit down into the basement and through the narrow staircase, which would ultimately mean having to use two tanks (each 400-500 L / 105-130 gallons) instead.
L
laien.haft20 Feb 2014 13:58Hello,
a solar thermal system for domestic hot water pays off quite quickly compared to the heating support version.
Without going into the system details too much (only an 800 l (210 gallons) buffer tank?), I would recommend choosing a system for domestic hot water preparation, especially if no underfloor heating is installed in the house. The return temperatures of conventional radiators do not contribute to the efficient operation of the solar system.
a solar thermal system for domestic hot water pays off quite quickly compared to the heating support version.
Without going into the system details too much (only an 800 l (210 gallons) buffer tank?), I would recommend choosing a system for domestic hot water preparation, especially if no underfloor heating is installed in the house. The return temperatures of conventional radiators do not contribute to the efficient operation of the solar system.
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