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.
T
T_im_Norden9 Feb 2020 09:18hegi___ schrieb:
And how does the pipe get to the roof? You don't vent the exhaust gases through the ground floor.
My Panasonic air-to-water heat pump costs 2500 euros and achieves an annual performance factor of 4.65.
You just have to size it correctly...The pipe is simply routed up through the roof; you don't need a chimney for that.The Geisha was actually a good solution, but its successor seems to have a somewhat lower annual performance factor.
If I wanted an air-to-water heat pump, I would have liked that one.
However, I am also considering a ground source heat pump because of the size of our property (ring trench collector possible).
What is your annual heat consumption?
Bookstar schrieb:
Do you have any sources for this false claim? However, I know that manufacturers design the systems for a maximum of 15 years, but these air-source heat pumps often fail after just 5 to 10 years. You can probably run a gas condensing boiler for 30 years without major repairs.
I don’t believe in heat pumps, even though I have one myself. Which, by the way, has already had many issues.In 2016, I looked into this in more detail. If you have more precise information that they are designed for 15 years, please share it with us. Stiebel officially states 15 to 20 years. For example, I was recently at a birthday of acquaintances who bought a house from the 1990s; their heat pump has been running since then. It’s not very efficient, but it works. So it shouldn’t even exist anymore, as it’s older than 20 years. Viessmann mentions 2 million heating systems in Germany that are older than 25 years. I don’t find that particularly many considering that a gas boiler can easily last that long. Reliable figures and long-term experience are simply lacking to have more than just opinions. Why did you choose a heat pump if you don’t believe in them? There are alternatives like pellet heating systems, for example.
T_im_Norden schrieb:
The pipe is simply routed up through the roof; no chimney is needed for it.
The Geisha was actually a good solution, but its successor seems to have a slightly lower annual performance factor.
If I wanted an air-to-water heat pump, I would have liked that one.
However, due to the size of our plot (ground loop collector possible), I am also considering a geothermal heat pump.
What is your annual heat consumption? I am still in the process of building myself.
I always refer to my brother’s house, which I planned and installed the building services for the year before last.
About 7800 kWh per year, which means roughly 40€/month heating costs including hot water. KfW 55 standard, 3 people, controlled ventilation with 90% heat recovery including drain water heat recovery.
What is often forgotten is that heating demand is higher during the first years due to moisture.
A ground loop collector installed by yourself can be worthwhile depending on the design temperature...
The difference compared to the old Geisha, calculated, was an annual performance factor lower by 0.05.
ares83 schrieb:
For example, at a friend’s birthday recently, they bought a house built in the 1990s where a heat pump has been running ever since—not very efficient, but it works. I bet the heat pump was sized like a conventional heating system and therefore doesn’t run efficiently...
Bookstar schrieb:
Just that no heating installer offers something like that. Including DIY solutions in the comparison feels like a hobby workshop approach, even if the solutions are often good.There are also other similar monoblock heat pumps that are somewhat more expensive and installed by companies.
For example, the pressure group from Grundstück Wärmesysteme, assuming you can negotiate properly...
Aside from that, the Geisha is not a DIY solution...
By the way, the house in the previous post is 150m² (1,615 ft²).
Nordlys schrieb:
I usually compare something like this with the Chinese gas boiler from Shenzhen Industrialpark Heating Solutions. $500 plus $5.95 shipping, and maybe some customs fees.If I remember correctly, you are also a fan of Polish windows. So why be so skeptical when it comes from even further East?
Apart from the fact that most heat pumps are also produced by regional manufacturers from the Far East, whether in development or manufacturing.
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