Underfloor heating air-water heat pump. House too warm when the sun shines

I now believe that the Novelan heat pump is particularly large technical junk. You really have to completely close the bypass valve and set everything manually. That's why I would prefer gas. The system always works perfectly without adjustment and the consumption figures are also right.

My Novelan still cycles twice a day and has an average compressor runtime of 45 minutes.

Then it is probably oversized. The problem with very "economical" houses is the low heating energy demand. There are hardly any suitable air-to-water heat pumps for that. Even the small ones often do not modulate down far enough.

Yes, it is, but the calculation turned out that way. Theory and practice. But all these problems only occur with heat pumps. As a customer, the risk of finding a company that masters this technology is very high. In our father's case, the brine system has already broken down after 5 years. Pump and compressor are failing. It's all rubbish. What the heating system cost him, I'd rather not say. He could have burned gas for 100 years.

Hehe, if my heat pump ever breaks down, it’s not a big deal. Just buy a new unit, put it in place, and connect it to the existing pipes. A straight 3,000€ + shipping. I really don’t understand why so many people buy such expensive heat pumps.

Partly, the customer service agents are just downright brazen and ignorant. For me, a valve on the hot water tank had to be replaced because it was dripping slightly. Suddenly, he started fiddling with the settings and just wanted to increase the hot water temperature, heating curve, and heating limit.

Hehe. After that went wrong with us for a year, I told my wife at the second to last maintenance to tell the technician right away not to mess with the settings. I think it worked. The last technician came... "oh, this is the house where the [ERR] were taken out of service and where you’re not supposed to adjust anything."

I am really impressed by what has accomplished here - WOW!
As an amateur, when I read the thread title, namely that rooms quickly become very warm or overheated in the sun, in my opinion it is primarily because a sluggish underfloor heating system is usually used. This system has many advantages and is probably considered standard at the moment, but THAT also seems to me to be a noticeable disadvantage alongside the many benefits.
Currently, we have an underfloor heating system that was probably installed in a rough-and-ready manner (it doesn’t belong to us). Today, for example, the sun is shining a bit and although we have hardly any direct sunlight despite many windows, it is noticeably warm, and without open doors and windows it would be uncomfortably warm for me, whereas otherwise it is well tempered here.
In the old house we had the classic radiator heating, and I generally prefer it a bit cooler and then heat up as needed (central heating or wood stove) or turn it back down again.
The problem mentioned here should therefore also occur with a gas heating system, and the cause is probably to be found in the underfloor heating rather than in a heat pump or gas heating system.
Or am I mistaken?
Unfortunately, the heating topic has not yet been discussed in detail with us, but especially because of the inertia of the underfloor heating, I am indeed considering installing a classic (disdained) radiator heating system, even if I would lose wall space for the radiators. We’ll see.....