First of all, hi everyone
We are planning to build a new house, specifically a KfW 70 standard home from Massa Haus with 160m² (1722 sq ft) of living space.
I’m still completely undecided about which heating system to choose.
There are no gas lines available, so we would need to rent a gas tank.
The standard package includes a gas boiler with a 300L (79 gallons) storage tank and about 5m² (54 sq ft) of flat-plate solar collectors.
A controlled ventilation system with heat recovery is always included.
For now, we have decided on an air source heat pump with underfloor heating (around €13,000). Since it is a compact system, the storage tank will probably be smaller. For an additional €1,500, we could add two high-performance evacuated tube solar collectors on the roof (about €14,500 extra compared to the standard package).
If we calculate differently and stick with the gas boiler, we would also have underfloor heating with a 750L (198 gallons) storage tank (160L domestic hot water and 590L buffer) for hot water and heating support, plus about 10m² (108 sq ft) of solar collectors (approximately €16,500 extra).
One advantage I’ve read about is that the heat pump has much lower maintenance costs (inspections, chimney maintenance, etc.).
I am really unsure about what to decide.
If we go with the heat pump, should we add the solar water collectors and save money, or is it better to invest more and install photovoltaic panels on the roof? (If you can even get anything useful for around €3,500.)
We are planning to build a new house, specifically a KfW 70 standard home from Massa Haus with 160m² (1722 sq ft) of living space.
I’m still completely undecided about which heating system to choose.
There are no gas lines available, so we would need to rent a gas tank.
The standard package includes a gas boiler with a 300L (79 gallons) storage tank and about 5m² (54 sq ft) of flat-plate solar collectors.
A controlled ventilation system with heat recovery is always included.
For now, we have decided on an air source heat pump with underfloor heating (around €13,000). Since it is a compact system, the storage tank will probably be smaller. For an additional €1,500, we could add two high-performance evacuated tube solar collectors on the roof (about €14,500 extra compared to the standard package).
If we calculate differently and stick with the gas boiler, we would also have underfloor heating with a 750L (198 gallons) storage tank (160L domestic hot water and 590L buffer) for hot water and heating support, plus about 10m² (108 sq ft) of solar collectors (approximately €16,500 extra).
One advantage I’ve read about is that the heat pump has much lower maintenance costs (inspections, chimney maintenance, etc.).
I am really unsure about what to decide.
If we go with the heat pump, should we add the solar water collectors and save money, or is it better to invest more and install photovoltaic panels on the roof? (If you can even get anything useful for around €3,500.)
Hello,
a lot has already been written about this. Try using the search function.
Without proper calculations (including heating load and consumption forecast) it is difficult to make a reliable recommendation. => Guesswork!
Best regards
a lot has already been written about this. Try using the search function.
DunDa schrieb:Liquefied petroleum gas has significant issues with modulation (minimum output). Solar thermal systems usually do not pay off in single-family homes.
....The standard setup includes a gas boiler with a 300L (79 gallons) storage tank and about 5m² (54 square feet) of flat plate collectors.
DunDa schrieb:Compact systems are often the worst choice.
.... Since it is a compact system,...
Without proper calculations (including heating load and consumption forecast) it is difficult to make a reliable recommendation. => Guesswork!
Best regards
That’s a good question regarding the heating load.
But if you say that the gas system is not so great and neither is the compact unit, what should I choose then? It shouldn’t exceed my budget either.
Choosing the gas boiler for now is the right decision, isn’t it?
Hmm, I thought it would be more practical, especially for supplemental heating.
But if you say that the gas system is not so great and neither is the compact unit, what should I choose then? It shouldn’t exceed my budget either.
Choosing the gas boiler for now is the right decision, isn’t it?
Hmm, I thought it would be more practical, especially for supplemental heating.
DunDa schrieb:
That’s a good question regarding the heating load. For necessary calculations, this might help:
https://www.hausbau-forum.de/threads/Erdwärmepumpe-wartung-wie-was-zu-beachten.4914/
DunDa schrieb:
...But if you say that the gas option isn’t so great, nor is the compact system, what should I choose then? An alternative could be a fully modulating inverter split system (air source heat pump) with appropriate capacity (performance curve). DunDa schrieb:
...But choosing the gas boiler at the moment is the right thinking, isn’t it? Actually not, because of the solar thermal system. Gas is more suitable in combination with the 15% rule (better insulation) and without a solar thermal system. For propane gas, some special considerations regarding the high minimum output must be taken into account to avoid frequent short cycling. DunDa schrieb:
...Hmm, I thought that would be something useful, especially for heating support. The seller probably thinks so, too. Unfortunately, when looking at the actual balance, the picture is completely different. Best regards,
Okay, that sounds plausible, but to be honest, I still don’t quite understand the gas part.
I need to check tomorrow whether I can exclude the heating system from the house package.
Because that way, I only have about 16,000 (currency) left for something else, and I probably won’t get anything for that, right?
I need to check tomorrow whether I can exclude the heating system from the house package.
Because that way, I only have about 16,000 (currency) left for something else, and I probably won’t get anything for that, right?
Hello Dunda,
The heating energy demand for a KfW 70 house is very low, so only small system capacities are needed. Due to the low demand, the potential for savings is also limited, and the importance of the energy source decreases. For this reason, investment costs play a larger role, as high investments must lead to significant cost savings. The advantage of gas condensing technology is that these investments are very low or, as in your case, the system is already included. If you want to take further steps now and truly reduce the consumption of fossil and nuclear-based energy, then solar energy remains the inexhaustible source. With a solar thermal system, which handles hot water generation and supports heating, there is an opportunity to contribute to environmental protection and partly decouple from energy price developments.
The heating energy demand for a KfW 70 house is very low, so only small system capacities are needed. Due to the low demand, the potential for savings is also limited, and the importance of the energy source decreases. For this reason, investment costs play a larger role, as high investments must lead to significant cost savings. The advantage of gas condensing technology is that these investments are very low or, as in your case, the system is already included. If you want to take further steps now and truly reduce the consumption of fossil and nuclear-based energy, then solar energy remains the inexhaustible source. With a solar thermal system, which handles hot water generation and supports heating, there is an opportunity to contribute to environmental protection and partly decouple from energy price developments.
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