Hello everyone,
I am planning to build a house this year and am currently looking into the heating system. I would like to hear some of your opinions.
I already had a meeting on this topic with our local energy consultant from the city. Together, we reached a similar conclusion to mine beforehand: a heat pump with ground drilling.
Another point discussed was a solar system on the roof (independent of whether solar thermal or photovoltaic at this stage). Since our roof is almost perfectly south-facing, this initially sounds very appealing. The energy consultant also recommended it under these conditions.
However, I have two concerns that are still troubling me: In a model calculation with the energy consultant, we assumed a required heat amount of about 10,000 kWh for our KfW70 house. With an annual performance factor (coefficient of performance) of 4, this results in 2,500 kWh of energy per year, or about 210 kWh per month. Assuming mostly night-time electricity (estimated price 14 cents/kWh), this leads to monthly costs of roughly €30.
The potential savings I could achieve with a solar system (especially solar thermal) seems very low to me. For a system costing €3,000, I would need to heat exclusively with my solar system for 100 months before it pays off. That could take forever...
The second point is that I recently realized the roof is mostly in shade during winter—the neighboring house is too tall. Even at midday, the sun probably won’t shine on the roof because it sits too low. Direct sunlight is mainly expected only in the morning.
I wonder if a solar system makes sense under these circumstances and would appreciate some assessments from your side. I have not discussed this with the energy consultant again yet, but that is still planned.
Looking forward to your feedback!
Best regards
Hügel
I am planning to build a house this year and am currently looking into the heating system. I would like to hear some of your opinions.
I already had a meeting on this topic with our local energy consultant from the city. Together, we reached a similar conclusion to mine beforehand: a heat pump with ground drilling.
Another point discussed was a solar system on the roof (independent of whether solar thermal or photovoltaic at this stage). Since our roof is almost perfectly south-facing, this initially sounds very appealing. The energy consultant also recommended it under these conditions.
However, I have two concerns that are still troubling me: In a model calculation with the energy consultant, we assumed a required heat amount of about 10,000 kWh for our KfW70 house. With an annual performance factor (coefficient of performance) of 4, this results in 2,500 kWh of energy per year, or about 210 kWh per month. Assuming mostly night-time electricity (estimated price 14 cents/kWh), this leads to monthly costs of roughly €30.
The potential savings I could achieve with a solar system (especially solar thermal) seems very low to me. For a system costing €3,000, I would need to heat exclusively with my solar system for 100 months before it pays off. That could take forever...
The second point is that I recently realized the roof is mostly in shade during winter—the neighboring house is too tall. Even at midday, the sun probably won’t shine on the roof because it sits too low. Direct sunlight is mainly expected only in the morning.
I wonder if a solar system makes sense under these circumstances and would appreciate some assessments from your side. I have not discussed this with the energy consultant again yet, but that is still planned.
Looking forward to your feedback!
Best regards
Hügel
K
K.Brodbeck17 Jan 2013 07:23Hello Hügel,
In my experience, solar thermal systems are not worthwhile when using a heat pump. We always recommend a photovoltaic system instead, which feeds excess electricity back into the grid. I’m not sure about the current subsidies, but photovoltaic systems have proven to be cost-effective after just a few years (also thanks to the financial incentives).
Best regards
K.Brodbeck
In my experience, solar thermal systems are not worthwhile when using a heat pump. We always recommend a photovoltaic system instead, which feeds excess electricity back into the grid. I’m not sure about the current subsidies, but photovoltaic systems have proven to be cost-effective after just a few years (also thanks to the financial incentives).
Best regards
K.Brodbeck
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