ᐅ Weishaupt (split system) or Kermi (monoblock unit)

Hello everyone,

We are currently trying to decide whether to choose a Weishaupt LS 8 air-to-water heat pump as a split unit or to go with a Kermi x-change dynamic ac 8 AW E monoblock instead.

The Kermi is said to be more efficient and can also use solar power "intelligently," but it comes with an extra cost of nearly 5,000. It’s clear that I won’t recover that 5,000 through more efficient operation alone, but maybe the maintenance costs are lower, the air-to-water heat pump is quieter, and so on.

Which option would you lean towards and why? What do you see as the pros and cons of these two units?

Thanks and best regards,
M. Gerd

M. Gerd schrieb:

The Kermi is supposed to be more efficient and can also use the solar power "intelligently," but it comes with an additional cost of nearly 5,000. It’s certain that I won’t recover the 5,000 through efficient operation alone, but possibly the maintenance costs are lower, the air-to-water heat pump is quieter, etc.

I have had the Kermi for a few weeks now, and it is extremely quiet... The photovoltaic system is already installed but not yet connected to the grid, so I can’t say anything about the "intelligent" usage yet.

Also, an IDM or Kermi simply looks much, much better than a Viessmann or a Weißhaupt.

Congratulations! My photovoltaic system is already installed on it, but unfortunately not yet connected because the power supply is not available yet.

Why did you choose the Kermi? In other words, what justified paying the significantly higher price for you? So far, on the pro side I have: noise level, efficiency, appearance, photovoltaic option. On the other hand, there are the high initial costs and the risk of pipes freezing in winter.

What about maintenance? Is the Kermi maintenance-intensive or rather low-maintenance?

M. Gerd schrieb:

Why did you choose Kermi? Or rather, what made you willing to pay the significantly higher price? So far, I see the advantages as noise level, efficiency, design, and photovoltaic option. On the other hand, there are the high initial costs and the risk of the pipe freezing in winter.

How about maintenance? Is the Kermi system maintenance-intensive or rather low-maintenance?

I’m located close to Kermi’s headquarters, and the IDM would have cost me almost the same as Kermi. Nothing else was really an option for me because I value quality and also care a bit about design. I also visited the Kermi factory to see the heat pump in person.
Why should the pipe freeze in winter? We installed a district heating pipe here, and the connections are insulated again, then covered with this aluminum cap. So, nothing should freeze there. I also got the X-Center Base and the Kermi switching actuators/room thermostats. Plus, the Kermi central ventilation system, so I have everything integrated into one system.

I can’t say yet how maintenance-intensive Kermi is, since it’s only been running for three weeks...

Hopefully, I will finally get my meters soon so the photovoltaic system can be connected to the grid...

Grantlhaua schrieb:

I hope I finally get my meters installed soon so the photovoltaic system can be connected to the grid...

It’s really enjoyable to see the electricity being generated. It’s currently overcast, no direct sunlight, it’s November, and right now I’m “harvesting” 1.3kW. Sometimes good news in the morning can be this small.

Yes, there is something to it; despite many clouds, 8 kW is coming in right now, thanks to the low temperatures.
The pump is heating the water nicely, the dishwasher is running, and an additional 6.5 kW is being fed in.