ᐅ Gas heating system without solar thermal integration?

Bieber0815 schrieb:
In Germany, you are only allowed to build a house if you comply with the Energy Saving Ordinance and the Renewable Energies Heat Act (in addition to other requirements, for example, the structural engineering must meet the standards). You cannot just build whatever you want.

Of course, I understand that—if it seemed otherwise. For example, we also have specific requirements regarding sound insulation.

sirhc schrieb:
Of course, that is clear to me—if it came across differently.

No, no, I just thought that statement might help clarify the requirements according to KfW.

sirhc schrieb:
For example, we also have special requirements regarding sound insulation.

I find that very interesting, by the way! From my very limited experience, that is a challenging area for many builders. They just don’t seem familiar with it... Good luck with the design of the mechanical ventilation with heat recovery, if desired.

Bieber0815 schrieb:

I find that very interesting, by the way! From my very limited experience, this is a difficult area for many contractors. They just don’t seem to know it ... Have fun designing the mechanical ventilation with heat recovery, if you want to.

How do you get from soundproofing to mechanical ventilation with heat recovery? Probably the same way I do. I don’t want to have to open any windows but still want to ensure air exchange. A central mechanical ventilation system with heat recovery is at the top of our list.

sirhc schrieb:
How do you get from soundproofing to controlled residential ventilation?

Because of the airflow noise, which needs to be minimized.

In this context (waiving solar thermal), I came across the following:

§ 7 Alternative Measures

(1) The obligation according to § 3 paragraph 1 or 2 is considered fulfilled if the obligated parties

1. cover at least 50 percent of the heating and cooling energy demand
a) from systems utilizing waste heat according to item V of the annex to this law, or
b) from combined heat and power (CHP) systems according to item VI of the annex to this law; § 5 paragraph 5 sentence 3, § 6 paragraph 1 sentence 1 and § 6 paragraph 2 apply accordingly,

Annex: Requirements for the Use of Renewable Energies and Alternative Measures
V. Waste Heat
1. If waste heat is used through heat pumps, items III.1 and III.2 apply accordingly.
2. If waste heat is used through mechanical ventilation systems with heat recovery, this use is only considered an alternative measure under § 7 paragraph 1 item 1 letter a if
a) the heat recovery efficiency of the system is at least 70 percent, and
b) the coefficient of performance, which is determined by the ratio of heat recovered and used from heat recovery to the electricity consumption for the operation of the mechanical ventilation system, is at least 10.

In simple terms: If you install a controlled residential ventilation system with heat recovery that has a heat recovery efficiency of at least 70%, you are allowed to waive solar thermal. Is that correct?

This would mean we have two options to waive solar: either a 15% better building envelope or a correspondingly efficient controlled residential ventilation with heat recovery. The latter is already planned, which would ultimately mean we can waive solar without incurring additional costs.

However, I don’t understand the addition about the coefficient of performance. Could someone please explain that in more detail?

Thank you very much!

I’ll bring up the chimney topic, depending on the federal state (in my case Baden-Württemberg):

Replacement measure for wood log burning applies if

- the chimney has an efficiency greater than 80%
- at least 30% of the living area is mainly heated with it