Weishaupt (Split) or Kermi (Monoblock)

are you getting a buffer tank? I actually only have it because of the photovoltaic system, as I store the excess energy in it. Storage systems are still too expensive and a large buffer is actually not profitable in heating operation either.

It's about time. How big are your systems & ? I'm curious to see how much energy actually comes down from the north side and how SolarEdge works then.

9.3 kWp - 22 kWh have already been fed in today, but due to the high output I was only able to use 30%.

9.99 kWp and currently 9.6 kWh battery, hot water storage still needs to be connected. Whether a battery storage is financially worthwhile or not essentially depends on the assumed charging cycles, assumed service life, and assumed price per kWh capacity, applied power loss over the years, and applied electricity price in the calculations. These assumptions are disputed - therefore both positions exist. These are each partially vehemently advocated.

After one year of operation, you can extrapolate how much electricity the battery saves over 10 years (and hopefully you were already aware beforehand that this results in a negative number) ...

So, we currently have 9.8kWp on a hip roof with SolarEdge. Additionally, a storage system from Sonnen... yeah yeah, demonize me. As already mentioned, there are two camps here and with our usage and consumption, it should pay off. Whether it will, we’ll see.

For heating, I would like to go with Kermi and also directly with the controlled residential ventilation from Kermi. Currently, the split device from Weishaupt and a Zehnder controlled residential ventilation system are planned. It’s not a bad alternative. They are good devices, and therefore I find the surcharge of 5k quite steep for just being a bit better. I just doubt that it is 50% better, given that it is that much more expensive.

For the heating, I would like to go with Kermi and then also directly with Kermi's controlled residential ventilation. Currently, the split unit from Weishaupt and a Zehnder controlled residential ventilation are planned. It's not a bad alternative. They are good devices, and therefore I find the surcharge of 5k quite steep, considering it is just a bit better. I doubt that it is 50% better, as it is that much more expensive.

How much does the Zehnder cost compared to the Kermi?

Is renegotiation no longer possible? Kermi is increasingly pushing into the heat pump market, and maybe something can still be done?

Where are you from?