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...
Baumfachmann schrieb:
Gas and solar thermal, simple, cheap, straightforward, and if the insulation is good, the consumption is minimal.That statement is too general. Depending on the production costs of gas, it may no longer be affordable. If the general contractor includes a heat pump as standard, you might still have to pay around 5,000€ for the chimney. On top of that, there is a gas connection at an unknown price (mine cost over 2,000€).
This has to be considered on an individual basis.
C
Caspar202012 Mar 2018 06:25Joedreck schrieb:
also a gas connection for an unknown priceAnd here, electricity, water, and gas cost less than just electricity and water alone. Only 2,000 (2k) for all three utilities, instead of 2,400 (2.4k) up to 10 meters (33 feet).
For us: a heat pump combined with gas plus solar thermal would have resulted in the same costs. We installed a trench collector ourselves for 2,500€ (about 2,750 USD), admittedly a rough estimate, but received a subsidy of 4,500€ (about 5,000 USD)... Overall, geothermal energy turned out to be cheaper than gas, with lower monthly expenses.
ruppsn schrieb:
Is that so? The payback period is – if I remember correctly – about 15 years (gas compared to an air-to-water heat pump). Admittedly, that’s a rough estimate, but it serves as a general guideline. However, people often only compare the boiler with the heat pump and the corresponding energy consumption. The fact that a chimney is absolutely necessary for gas, which costs money, is often not included in the calculations. Maintenance costs for heat pumps are frequently criticized, but the regular visit from the chimney sweep is conveniently overlooked.
Personally, I find it makes little sense to rely on a limited energy source (oil, natural gas) that will inevitably become more expensive. Of course, certainty would come from looking into a crystal ball, but that’s currently broken.
I have indeed considered gas myself and don’t want to dismiss it completely, but pretending it is the only sensible and economical solution is simply nonsense. It depends too much on the conditions, such as usage patterns, number of occupants, insulation standards, house location, and so on. But then you must not rely on electricity. If the government continues to promote everything using electricity like this, I seriously wonder where all that electricity will come from. Is the entire Saarland going to be converted to electricity then?
Nordlys schrieb:
That’s not entirely correct. The required renewable energy shares could also be covered with a photovoltaic system if, for example, you chose a gas boiler without domestic hot water and supplied hot water with electricity through an instantaneous water heater. However, this would not be economical. Photovoltaic systems are much more expensive compared to solar thermal systems. I think you pay a 200% premium.A photovoltaic system is the only part of the entire house that typically pays off in about 15 years! Also, photovoltaic systems are not excessively expensive nowadays. Of course, they’re not free, but a kilowatt-peak (kWp) costs around 1100–1000€ on a good offer.
But if you’re already considering the price difference between a heat pump and gas and how it balances out with a few thousand euros difference, how does it look for the rest of the house?!
Caspar2020 schrieb:
And for us, electricity, water, and gas together cost less than just electricity and water. Only 2,000 (2k) for all three, instead of 2,400 (2.4k) up to 10,000 (10k)That’s exactly why individual calculations are important. You cannot make general statements with confidence.Similar topics