Company Lüumel, trench collector

What are they supposed to be read out for? You don't have to prove the annual performance factor - BAFA also knows that there can be discrepancies there.

A not extensively described QS check must be done (which didn't even exist in the first version of the application)...

As I said, I think you misunderstood something or had Mr./Ms. Incompetence on the phone.

I found this on the BAFA homepage:

"Basic funding requirements:
For electrically driven heat pumps: Installation of an electricity meter to record all electricity consumed by the heat pump; for gas-powered heat pumps: Installation of a gas meter to record all fuel consumed by the heat pump.
Installation of at least one heat quantity meter. The measurement of all heat quantities delivered by the heat pump is mandatory."

Yes, you're probably right, that's why I'm so glad that there are forums like this one. As I said, I also find a heat quantity meter costing 900€ a bit steep.

Ok, I installed an external electricity meter plus the internal measuring device plus an internal heat meter (manufacturer Vaillant).

So at least on the safe side.

Hello, we have also had a heating system with trench collector from the company Lüumel since 2016. Unfortunately, we have 2 malfunctions every year. It apparently always lacks refrigerant, now our system is very, very loud when starting up, we were told that it was due to the missing refrigerant. Can someone confirm the noise level of the heating system? Thank you very much!

Our heating was also very loud at the beginning, especially because we rarely kept the door completely closed due to the cat litter boxes in the heating room. We then attached 4-5 cm thick heat-resistant insulation mats all around behind the fixed cover panels with double-sided adhesive tape. You can still hear the heating, but it has become significantly quieter.

You might be able to unscrew a panel now and take a look at the cutout for the pipes. When we commissioned it, a small piece of insulation mat was placed over the cutout, which had come loose. That left the hole open. If that is also the case for you, it helps somewhat to reattach the insulation piece.

Since we discussed the issue of the submeter earlier, it has been installed for 2 years.

If you are interested in the consumption, I posted it in another forum: You can find it under the keywords "Bau Hilfe Forum" in the thread "Was verbrauchen eure Heizungen".

Thank you very much for the quick response. I will take a look at the topic of consumption right away. We have a separate heating electricity meter, about 8000 kWh in the first year, similar in the second...