Hello everyone,
We currently live in a house (built in 2015, rented) with the following energy consumption values:
We have looked into solar options (both photovoltaic and thermal) to support or power an air-source heat pump, but financially it doesn’t seem to add up. Additionally, our house will have a gable roof aligned exactly north-south, meaning one roof side faces east and the other west.
We currently live in a house (built in 2015, rented) with the following energy consumption values:
- Household electricity: 3,000 kWh per year
- Air-source heat pump: 4,300 kWh electricity per year, heating output 13,000 kWh
- Solar thermal system: 1,000 kWh thermal energy
We have looked into solar options (both photovoltaic and thermal) to support or power an air-source heat pump, but financially it doesn’t seem to add up. Additionally, our house will have a gable roof aligned exactly north-south, meaning one roof side faces east and the other west.
- For the photovoltaic system, I initially considered a battery so we wouldn’t have to feed electricity into the grid for very little compensation and could instead use the generated power for the air-source heat pump. However, such a battery quickly costs upwards of 6,000 euros; for that price, you could pay for gas for 8 years. In other words, even if it were a perfect battery that supplied all the electricity for the heat pump at no cost, it would need to last at least 8 years. This doesn’t even take into account that the air-source heat pump itself is also more expensive than the gas heating system.
- I am skeptical about solar thermal because during the summer months, when the sun is strongest, you actually need the least hot water. Electricity, at least household electricity, is always needed.
- Is it possible to install a gas heating system if you only build according to the energy-saving regulations (e.g., EnEV / energy performance requirements) without installing anything on the roof? Or would that not comply with the maximum allowed primary energy demand?
- What about using only an air-source heat pump (like we have now in our rental)? Somehow it is so expensive that it never really pays off compared to gas, regardless of whether you have photovoltaic or solar thermal on the roof. Gas is just too cheap...
J
junge_familie11 Mar 2018 09:53How does it actually work if we install a gas heating system and then put photovoltaic panels on the roof for household electricity? Is that possible, or would it not be allowed and solar thermal system would be required instead? I mean from the perspective of energy-saving regulations...
junge_familie schrieb:
How does it actually work if we install a gas heating system and then put photovoltaics on the roof for household electricity? Is that possible, or would we have to use solar thermal instead? From the perspective of energy saving regulations...
If you use gas heating, you also have to install solar thermal systems. The regulations require a certain percentage of renewable energy.
That is not entirely correct. The required renewable energy shares could also be covered by photovoltaic systems (PVI), for example, if one chooses a gas boiler without hot water heating and uses electricity or an electric water heater for hot water. However, this would not be economical. Compared to solar thermal systems, PVI is far too expensive. I think it costs about 200% more.
J
junge_familie11 Mar 2018 10:34OK, so it will be solar thermal combined with the gas heating after all... It’s a bit inconvenient since using electricity from photovoltaics would offer more flexibility. That way, in a few years, you could also charge a possible electric vehicle right away...
Or we start with gas and solar thermal and already install the wiring for photovoltaics on the roof!?
Or we start with gas and solar thermal and already install the wiring for photovoltaics on the roof!?
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