Hello everyone!
A quick question:
Why do people actually add solar thermal systems to their gas heating?
Is it because they have to comply with the energy saving regulations?
Wrong, you are allowed to skip solar thermal if other measures reduce energy consumption by at least 15%.
Example:
I’m planning a KfW-55 house with gas heating, solar thermal, controlled ventilation with heat recovery, and excellent insulation.
Now I remove the solar thermal system. What happens?
I lose the KfW-55 status and end up with KfW-70, so I lose a €2,500 subsidy. But I save €6,000 by not installing solar thermal. The operating costs increase by €50 per year due to the missing solar thermal, which adds up to €1,000 over 20 years. So overall, I still save €2,500.
Savings:
€6,000 saved by not installing solar thermal*
- €2,500 lost KfW-55 subsidy
- €1,000 higher operating costs due to no solar thermal*
=======
€2,500
Sounds like an attractive alternative, or is there a major calculation mistake somewhere?
The whole calculation would also apply to a KfW-85 house, which would qualify as a KfW-100 house without the solar thermal.
Best regards
jx7
PS:
Please don’t bring up heat pumps or pellet heating; this is not meant to start a fundamental debate about gas versus heat pumps (with sharp increases in energy prices, heat pumps will eventually become more cost-effective). The initial question is simply: "If using gas, then maybe without solar thermal?"
* Source: xxx-Heizungsvergleich-de "Gas + 5sqm solar thermal"
A quick question:
Why do people actually add solar thermal systems to their gas heating?
Is it because they have to comply with the energy saving regulations?
Wrong, you are allowed to skip solar thermal if other measures reduce energy consumption by at least 15%.
Example:
I’m planning a KfW-55 house with gas heating, solar thermal, controlled ventilation with heat recovery, and excellent insulation.
Now I remove the solar thermal system. What happens?
I lose the KfW-55 status and end up with KfW-70, so I lose a €2,500 subsidy. But I save €6,000 by not installing solar thermal. The operating costs increase by €50 per year due to the missing solar thermal, which adds up to €1,000 over 20 years. So overall, I still save €2,500.
Savings:
€6,000 saved by not installing solar thermal*
- €2,500 lost KfW-55 subsidy
- €1,000 higher operating costs due to no solar thermal*
=======
€2,500
Sounds like an attractive alternative, or is there a major calculation mistake somewhere?
The whole calculation would also apply to a KfW-85 house, which would qualify as a KfW-100 house without the solar thermal.
Best regards
jx7
PS:
Please don’t bring up heat pumps or pellet heating; this is not meant to start a fundamental debate about gas versus heat pumps (with sharp increases in energy prices, heat pumps will eventually become more cost-effective). The initial question is simply: "If using gas, then maybe without solar thermal?"
* Source: xxx-Heizungsvergleich-de "Gas + 5sqm solar thermal"
jx7 schrieb:
The Energy Saving Ordinance and KfW funding are two completely different things.
These are all details related to the 2009 Energy Saving Ordinance, which still apply to you.
I would be interested to know what your price comparison showed. I would strongly guess that without solar thermal, it’s much cheaper, so that the lower consumption costs with a solar thermal solution are not enough to offset the additional costs of solar thermal within the first 20 years.
But okay, the 2009 Energy Saving Ordinance is now outdated. I’m not familiar with the new regulations; I assume that with a gas heating system, solar thermal is now mandatory.
jx7Hello jx7,
So, do I need proof of compliance with the Energy Saving Ordinance and not a KfW certification? Even though they are completely different, they seem somewhat connected.
The solar package costs about 3,100 EUR, while the additional cost for the KfW 70 certification is 1,650 EUR—and I’m still not entirely clear whether I actually need that or not.
There might be some extra costs for insulation, but even if it were cost-neutral, the additional insulation should require much less maintenance and carry a lower risk of failure than the solar package.
That’s why I’m asking how exactly the 15% reduction needs to be demonstrated.
Best regards
The methods for demonstrating compliance with the Energy Saving Ordinance are basically the same as for the KfW certification, namely a calculation of the two key values. Nevertheless, our energy consultant wanted an additional 500 € if, besides the Energy Saving Ordinance certificate, a KfW 70 certificate also had to be provided, allegedly because more formalities need to be completed (including verification of the correct implementation of measures, site inspection, etc.). The KfW 55 certificate is even more complex.
An Energy Saving Ordinance certificate must be prepared in any case; the costs apply regardless of whether the building is constructed with gas plus solar thermal or with gas and the 15-percent rule. The Energy Saving Ordinance certificate may already be included in the house construction contract.
An Energy Saving Ordinance certificate must be prepared in any case; the costs apply regardless of whether the building is constructed with gas plus solar thermal or with gas and the 15-percent rule. The Energy Saving Ordinance certificate may already be included in the house construction contract.
jx7 schrieb:
An energy performance certificate is mandatory regardless; the costs apply whether the building uses gas plus solar thermal or gas with the 15-percent rule. The energy performance certificate may already be included in the construction contract. Thank you – 3,100 EUR gross just for material costs. We will definitely try to comply with the 15-percent rule, which is why we made every effort to submit the application before the end of the old year. As you said, the energy performance certificate is already factored in, so this makes the 15-percent rule option even more advantageous.
The new regulations no longer allow installing just a gas heating system. In my opinion, solar does not pay off, even if no maintenance or repairs are needed. So we prefer to forgo it altogether.
Best regards
B
Bieber08157 Jan 2016 15:44sirhc schrieb:
KfW 70 certification costs around 1,650 EUR (approximately $1,770) – and I still don’t fully understand whether I actually need it or not. If you want to apply for an efficiency loan through the KfW (usually arranged via your bank), then you need the KfW certification (details can be found in the information sheet for the respective KfW loan program). If you are not taking out an efficiency loan, this proof is not required.
So, the additional cost of 1,650 EUR (approximately $1,770) should be weighed against the interest savings of an efficiency loan compared to a standard loan.
In hindsight, I might even go without KfW financing.
From the beginning, I wanted the complete package from a single source. Two banks, two loans—senior and subordinated—I wasn’t interested in all that hassle just to save a few tenths of a percent on 1/5 of the total amount. Besides, the interest rate advantage is practically wiped out by the additional costs. So I thought, better to just keep it simple.
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