We are planning a new build. The footprint of the house: 10 x 14.5 meters (33 x 48 feet). Ground floor: a household of two retirees. Upstairs, a self-contained apartment for one person.
Heating options / power supply:
a) standard gas boiler
b) ground source heat pump, electricity from the grid
c) ground source heat pump, electricity from own photovoltaic system and possibly battery storage
d) ground source heat pump, electricity from own photovoltaic system, battery storage, and possibly cloud services
So far, we have no information about the price difference between purchasing a standard gas boiler and a ground source heat pump.
Two construction companies said a standard, affordable gas heating system would be sufficient since houses today are so well insulated that the heating demand is not very high. But is that future-proof?
And if a heat pump is chosen, is it better to have electricity supplied from an own photovoltaic system? With or without storage? In addition, a cloud solution?
Heating options / power supply:
a) standard gas boiler
b) ground source heat pump, electricity from the grid
c) ground source heat pump, electricity from own photovoltaic system and possibly battery storage
d) ground source heat pump, electricity from own photovoltaic system, battery storage, and possibly cloud services
So far, we have no information about the price difference between purchasing a standard gas boiler and a ground source heat pump.
Two construction companies said a standard, affordable gas heating system would be sufficient since houses today are so well insulated that the heating demand is not very high. But is that future-proof?
And if a heat pump is chosen, is it better to have electricity supplied from an own photovoltaic system? With or without storage? In addition, a cloud solution?
L
ludwig88sta18 Dec 2019 13:10hegi___ schrieb:
Yes, I will also be installing these.
The electric heating element switches on starting from the bivalence point. This depends on the load and operating mode—usually around -5°C to -9°C (23°F to 16°F).
The heat pump itself ideally should not be used below -20°C (-4°F) overall. But that is quite unlikely in our case. Yes, the minimum temperatures really vary a lot depending on the latitude in Germany. In the south, you will probably need an air-to-water heat pump with a lower bivalence point.
**Edit: Are there air-to-water heat pumps that activate a small gas boiler at the bivalence point instead of an electric heating element?
ludwig88sta schrieb:
@hegi___ So you will also be installing the newer "WH-MDC05H3E5"?
Because I am currently looking at the data for this heat pump. It says "operating range down to -20°C (–4°F)." What actually happens if it gets colder? Does that mean the electric heater only turns on from -20°C (–4°F) and then you basically heat 1:1 with electricity, or how does that work? That’s the case, or something similar, with every air-to-water heat pump. It can freeze as well. There are also heating elements for automatic defrosting, and so on.
ludwig88sta schrieb:
**Edit: Is there actually an air-water heat pump that switches on a small gas boiler when the bivalence point is reached? Instead of an electric heating element.That would basically defeat the whole purpose. Because then you would need a gas boiler system and a gas connection again, etc. The costs would outweigh the benefits.L
ludwig88sta18 Dec 2019 13:46Mycraft schrieb:
That would actually lead the whole concept to absurdity. Because then you would still need a L.P.G. tank and a gas connection, etc. The costs would outweigh the benefits. But if the gas connection is already on the property and you basically only pay for the gas you use, then for about 1-2% of the total operating time per year, when the system falls below the crossover temperature, it could make sense. Of course, even though heating with electricity (meaning the electric heating element is on because it’s below the crossover point) during that short time is relatively expensive, it would still clearly be more economical than buying and maintaining a small additional gas boiler / burner plus the L.P.G. tank costs, and so on. That’s true.
L
ludwig88sta18 Dec 2019 13:54hegi___ schrieb:
Yes, I will be installing these as well.
The heating element is activated from the balancing point, which depends on the load and operating mode—typically between -5°C and -9°C (23°F and 16°F).
The heat pump should generally not be used below -20°C (-4°F). But that is rather unlikely in our area. I quickly searched on DuckDuckGo and found articles reporting significant subzero temperatures in Bavaria over recent winters (the most extreme was at Funtensee on February 28, 2018, at -40.3°C (-40.5°F)). If I’m building in an area where temperatures can drop to -20°C (-4°F) and the heat pump turns off at that point, ideally I would use the installed fireplace for heating, right? Otherwise, wouldn’t you end up in a house that’s unheated overnight?
But I also understand that temperatures of -20°C (-4°F) are becoming increasingly rare.
There is a "heat pump climate map" where you can read the relevant temperatures.
Where is the problem if the electric heating element turns on once a year? That’s exactly what it’s designed for.
With smart controls, you ideally heat the house only around midday when your photovoltaic system is generating electricity.
Where is the problem if the electric heating element turns on once a year? That’s exactly what it’s designed for.
With smart controls, you ideally heat the house only around midday when your photovoltaic system is generating electricity.
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