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.
Attention, a genuinely serious question. Is the environmental impact of a “wooden house” really better in the long term compared to a masonry house?
I’m not sure how energy-intensive concrete actually is, but on one hand, a solid house is only partly made of concrete, and on the other hand, from a layperson’s perspective, I would think that stone lasts much longer than wood. Quite simply, the pyramids and castles are still standing, but ancient pile dwellings or wooden houses have all disappeared.
Once again, a truly serious question.
We would have preferred a wooden house, but in the end, the costs and the architect’s expertise did not allow it.
I’m not sure how energy-intensive concrete actually is, but on one hand, a solid house is only partly made of concrete, and on the other hand, from a layperson’s perspective, I would think that stone lasts much longer than wood. Quite simply, the pyramids and castles are still standing, but ancient pile dwellings or wooden houses have all disappeared.
Once again, a truly serious question.
We would have preferred a wooden house, but in the end, the costs and the architect’s expertise did not allow it.
T
T_im_Norden22 Apr 2020 13:41If you care about ecology and sustainability, buy an existing property.
Photovoltaic systems no longer pay for themselves; most installations need to run for 10 years just to recover the purchase price. If you add a battery storage system, you pay extra on top of that.
Photovoltaic systems no longer pay for themselves; most installations need to run for 10 years just to recover the purchase price. If you add a battery storage system, you pay extra on top of that.
T
T_im_Norden22 Apr 2020 13:49blubbernase schrieb:
How does the decision I make today affect my modernization options in the future? If I want to upgrade the heating system in 15 or 20 years, will I limit myself by choosing one of the options available today? Or does it not matter? This is not a problem with proper planning.
I had my underfloor heating designed for 30/23 at 20 to 22 degrees Celsius (68 to 72°F).
So if, in a few years, gas becomes extremely expensive and it makes sense to switch, I would only need to remove the boiler and connect a heat pump.
K
knalltüte22 Apr 2020 14:23T_im_Norden schrieb:
If your focus is on ecology and sustainability, buy an existing property.
Solar panels no longer pay for themselves; most systems need to run for 10 years just to cover the purchase cost. If you add a battery storage system, you end up paying extra. Sorry, that’s nonsense. Solar panels do pay for themselves—do they just disappear into thin air after 10 years?
What about after 15, 20, or 25 years? OK, batteries in the storage system can fail—replace them—and that’s it.
The return on investment is probably around 2-4% (or more, depending on the individual situation).
I just want to offer some suggestions and don’t intend to start a fundamental debate here.
Everyone should form their own opinion (and be able to calculate correctly).
Regarding battery storage: it almost never makes economic sense, I agree with you there.
Also, the energy lobby is indeed pushing for some "absurd" policies. But the 52GW cap hasn’t been reached yet, and what will apply next year? I have no idea.
Download solar radiation data (to understand the system), plan the specific property, and then decide.
P.S.: I’m a solar panel layman, haven’t understood everything yet, but I have all the necessary information for calculations.
P.P.S. I already own an existing property; otherwise, I don’t have another one available privately here, and traveling further (beyond what I can reach by bike) doesn’t make ecological sense either.
guckuck2 schrieb:
An investment that has paid back after 10 years has a return of 10%.
And that's with a guaranteed feed-in tariff for 20 years.
Everyone has to decide for themselves, my roof is fully booked No: compound interest.
7.18% would be the return, assuming no inflation or taxes. If I have calculated correctly. Investment calculations were never my strong suit, and I didn’t have to do it for 10 years. Someone is welcome to check it here.
Still, I think it’s a good interest rate...
Similar topics