ᐅ Gas with solar thermal? Or heat pump with photovoltaic? Advice needed
Created on: 5 Feb 2020 08:57
M
Micha8589
Good morning to the forum,
I have been researching heating options for quite some time and have gathered a few opinions, which have only made me more uncertain about my decision. That’s why I thought I’d ask the forum.
My family (2 adults, 1 child) is planning to build the following single-family house at the end of this year or beginning of next year:
Single-family home with pitched roof
Approximately 115 m² (1,237 sq ft)
Solid construction (calcium silicate brick ground and upper floors, brick-clad)
No KFW standard
Building location: southern Mecklenburg
Unfortunately, I can’t provide an energy performance certificate or heating load calculation yet, as the preliminary offer is still being prepared. I am also aware that a general statement can’t really be made since every house and heating behavior is individual.
The construction company advised us to install a modern hybrid heating system consisting of a gas condensing boiler and two solar thermal panels on the roof for domestic hot water, as the initial costs are relatively low (plus installation of the central gas connection), and this technology has proven reliable. The entire house is planned to have underfloor heating. According to the company, they have had very positive experiences with this and consider the technology future-proof. (There is also the idea of a fireplace in the living room.)
On the other hand, I think gas prices will not get any cheaper in the future, and the topic of CO₂ taxes (especially concerning the fireplace) worries me somewhat.
In theory, I would prefer to install a geothermal heat pump combined with a suitable photovoltaic system because this would make me independent of fossil fuels and allow me to heat “off-grid” to a certain extent, depending on efficiency. However, I am hesitant because of the very high initial costs and don’t really know how these compare to operational costs. I also can no longer realistically assess which technology offers the best cost-performance ratio (except for air-source heat pumps).
As you can see, I am completely undecided and hope to get some feedback and expertise from the forum.
Thanks in advance for your replies.
I have been researching heating options for quite some time and have gathered a few opinions, which have only made me more uncertain about my decision. That’s why I thought I’d ask the forum.
My family (2 adults, 1 child) is planning to build the following single-family house at the end of this year or beginning of next year:
Single-family home with pitched roof
Approximately 115 m² (1,237 sq ft)
Solid construction (calcium silicate brick ground and upper floors, brick-clad)
No KFW standard
Building location: southern Mecklenburg
Unfortunately, I can’t provide an energy performance certificate or heating load calculation yet, as the preliminary offer is still being prepared. I am also aware that a general statement can’t really be made since every house and heating behavior is individual.
The construction company advised us to install a modern hybrid heating system consisting of a gas condensing boiler and two solar thermal panels on the roof for domestic hot water, as the initial costs are relatively low (plus installation of the central gas connection), and this technology has proven reliable. The entire house is planned to have underfloor heating. According to the company, they have had very positive experiences with this and consider the technology future-proof. (There is also the idea of a fireplace in the living room.)
On the other hand, I think gas prices will not get any cheaper in the future, and the topic of CO₂ taxes (especially concerning the fireplace) worries me somewhat.
In theory, I would prefer to install a geothermal heat pump combined with a suitable photovoltaic system because this would make me independent of fossil fuels and allow me to heat “off-grid” to a certain extent, depending on efficiency. However, I am hesitant because of the very high initial costs and don’t really know how these compare to operational costs. I also can no longer realistically assess which technology offers the best cost-performance ratio (except for air-source heat pumps).
As you can see, I am completely undecided and hope to get some feedback and expertise from the forum.
Thanks in advance for your replies.
guckuck2 schrieb:
I’m not arguing, I’m just repeating what was said. Alright then, I find the argument you’re repeating questionable.
guckuck2 schrieb:
You, on the other hand, are arguing, I’m not arguing either, but rather presenting connections and facts.
guckuck2 schrieb:
with your crystal ball. How else should I predict future developments? Obviously, you have a more reliable tool at hand.
guckuck2 schrieb:
current political will If only politics knew what it wanted. Nuclear phase-out, yes. No, wait. Yes! CO2 pricing must come. A little. More! This back-and-forth about doing away with the Renewable Energy Act and replacing it with CO2 pricing is nothing more than a compromise between Green-Red and Black party interests. One side wants a price on CO2, the other wants to get rid of the Renewable Energy Act surcharge. That’s the deal (“political will”). Reducing electricity prices was NEVER the goal; that could be handled much more easily with the right tax cuts. This is all about balancing interests in a way that can still be presented nicely to voters.
hegi___ schrieb:
Despite all the speculation, the fact is that with photovoltaics I can operate partially self-sufficiently Are you trying to trigger me? Self-sufficient means having no grid connection. If even 1 kWh passes through your meter (in either direction), you are definitely not self-sufficient. Neither fully nor partially.
MayrCh schrieb:
Alright, then I consider the argument you are presenting to be questionable.
I am not arguing either, but rather presenting connections and facts.
How else am I supposed to predict future developments? Obviously, you have a more valid tool at hand.
If only politicians knew what they wanted. Phase-out of nuclear power, yes. No, wait, not really. Yes! There must be a CO2 price. A little. More!
This back-and-forth about the Renewable Energy Act disappearing and being replaced by CO2 pricing is nothing more than a compromise between the interests of the Red-Green coalition and the Conservatives. One side wants a price on CO2, the other wants to get rid of the Renewable Energy Act surcharge. That’s the deal ("political will"). It was NEVER about lowering electricity prices; that could be much easier accomplished with appropriate tax cuts. This is about balancing interests while packaging it appealingly for voters, ideally.
You’re trying to trigger me, right? Off-grid means having no grid connection. If even 1 kWh goes through your meter (regardless of direction), one thing is certain: you are not off-grid. Neither fully nor partially.
T_im_Norden schrieb:
Could you describe how you implemented this, which heat pump you used, and the cooling system setup so that others might be able to do it themselves? To test the cooling function via the underfloor heating system, a Rotex HPSU was used at that time.
Now, a Daikin Altherma is used (which is basically the same type of device). This cools the air directly rather than through the underfloor heating system. Yes, colloquially, this is called an "air conditioning system," but technically it is and remains a heat pump.
hegi___ schrieb:
He probably has a reversed heat pump—basically an air conditioner. There is nothing reversed about it. A heat pump is a heat pump regardless of the heat source medium and regardless of whether the device is used for cooling or heating.
It also doesn’t matter if the device is used in a washer-dryer, refrigerator, or, for example, for water heating. Heat can be transported in both directions.
However, simpler devices often only operate in one direction because it is frequently not necessary for them to do both.
S
Schlenk-Bär11 Feb 2020 20:41Mycraft schrieb:
For testing the cooling function via the underfloor heating, a Rotex HPSU was used back then.
Now a Daikin Altherma is being used (Daikin basically represents the same type of unit). This one cools the air directly instead of the underfloor heating. Yes, colloquially this is called an "air conditioner," but technically it is and remains a heat pump.Just to make sure I understand correctly: Heating is done via underfloor heating with gas, and cooling is done via controlled mechanical ventilation with an air-to-air heat pump, is that right? Thanks for your feedback.No, the controlled ventilation system has nothing to do with this; it does not provide the necessary air volume to achieve effective cooling. However, it remains on even during the cooling operation.
Otherwise, yes, heating is done with gas through the underfloor heating system, and cooling is provided by an air-to-air heat pump. In my case, this was the most cost-effective solution. Although cooling is optional, I still recommend it to everyone (in addition to a shading concept) since summers are getting warmer, but ultimately, it is a personal decision.
Otherwise, yes, heating is done with gas through the underfloor heating system, and cooling is provided by an air-to-air heat pump. In my case, this was the most cost-effective solution. Although cooling is optional, I still recommend it to everyone (in addition to a shading concept) since summers are getting warmer, but ultimately, it is a personal decision.
S
Schlenk-Bär11 Feb 2020 20:56Mycraft schrieb:
No, the mechanical ventilation system with heat recovery doesn’t provide the required air volume to achieve effective cooling. But it stays on regardless during cooling operation.
Otherwise, yes, heating is done with gas through underfloor heating... cooling with an air-to-air heat pump. In my case, this is the most economical solution. Although cooling is optional, I still recommend it to everyone (in addition to shading solutions) since summers are getting warmer, but everyone has to decide for themselves. Sorry, but I don’t understand. If the cooling does not work through the mechanical ventilation system with heat recovery, but it still runs, then in summer you are drawing warm outside air into the house, right? If the mechanical ventilation system with heat recovery and the air-to-air heat pump are separate, do you have separate air supply and exhaust outlets in each room?
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