ᐅ GAS / SOLAR or GAS / Ventilation with Heat Recovery

Hello,

We currently have an offer for a new build.
For the heating system, we were given the following options:

Gas/solar
or a ventilation system Lunos-E2 with heat recovery, which is 1000.- cheaper (compared to solar).

Now I’m quite uncertain about which option is better.
However, I tend to choose the ventilation with heat recovery (instead of gas/solar with basic ventilation).
Price is not the deciding factor.

Any ideas/questions/advice?

Best regards,
M.

Would both options meet the KfW70 standard according to your supplier? Or does it not matter to you?

Personally, I would choose both regardless; I might be more willing to skip solar. However, I’ve heard that it’s important to at least plan for the possibility of solar installation later on.

Oh... wait, I just read that you would also have ventilation with gas/solar... I wanted to suggest not to skip ventilation because of the risk of mold.

Well, I don’t have any solid arguments or data—it's more of a gut feeling... a fact-based answer will probably come later.

Ok, running the pipes up to the roof is definitely a good argument.
It will remain KfW70 in both cases.

I assume the potential savings would be about the same for both?

brian73 schrieb:
...Regarding the potential savings (I suppose), wouldn’t they be about the same for both?

Hardly. Where does that assumption come from? Has the HVAC planner calculated it?
Furthermore, I doubt that a KfW approval will be granted if the EEWG requirements are not met! Penalties for violations here are just as high as for breaches of the Energy Saving Ordinance.

Best regards

Hello €uro,

€uro schrieb:

Penalties here are just as high for violations as they are for breaches of the Energy Saving Ordinance.

However, the Energy Saving Ordinance can appear to be easily met "on paper"...

These days, I often wonder if the inspectors are all asleep...

Best regards, Bauexperte

Hello construction expert,

Bauexperte schrieb:
...The energy saving ordinance can be easily met "on paper" ...

not only that, it is similar with KfW as far as just the paperwork is concerned.
Differences do exist, though. With KfW, at least the documents are checked for plausibility. With the energy saving ordinance, at best, the completeness of the documents is ticked off. It is generally the case that a processor at a local building authority is completely overwhelmed both in terms of time and expertise.
No claimant, no judge. However, the problem with the whole issue (energy saving ordinance, EEWG) is that the builder is legally responsible externally.
With KfW funding, at least partly, the preparer is also involved, but not in the execution.
Construction supervision is only required starting from KfW 55.

Best regards