Does a storage oven and KfW40-Plus house make sense?

Hello,
we are currently building a KfW40-Plus house. The house will be so well insulated that we will need a maximum of 15 kW/sqm heating energy per year.
At the moment we are considering whether to install a nice fireplace. The problem is, you then also need a good masonry heater or storage fireplace that releases only a little energy immediately and stores the rest first, then emits it evenly as radiant heat over many hours.
We now have two offers, ranging from 15,000 to 20,000 euros per fireplace. But the underpressure monitor, which is also needed (we have a ventilation system), is not yet included.

My question is, who has a very well insulated house and a fireplace? How often do you really use it? Do you have problems with overheating the rooms?
What is your opinion on this? Plan it in or leave it out?

Yes.
Almost daily in winter.
Yes.
Window open.
Hobby.

Yes, we use it quite often. The stove has no storage stones, heat is released directly into the room and basically dissipates unused (power over 10kW). Temperature increase in the large, open living/dining area during the evening is about 2-3 degrees. So no overheating, no open window, just enjoying the fireplace. This is what the combustion chamber looks like (with a pressure monitor that is no longer visible later), during construction and finished. Price at approx. T€ 10 complete.

We use it almost daily (but have only been in the house for a few weeks, let's see how it looks next winter). It is a fireplace insert and lined with firebricks, so it also stores "a little" heat. Temperature increase during the evening is currently about 3 degrees, although that certainly also depends heavily on how much and how often you add wood. After a few hours you can still feel the warmth, but the next morning usually not anymore. Our calculated heating load is just under the one you mentioned above. Price for the stove with installation ~ 9,000 EUR.

Hello

Did the chimney sweep suggest / specify the solution with the differential pressure switch with you? Why?

Olli

Moin Moin

Did the chimney sweeps suggest / mandate the solution with the differential pressure monitor at your place? Why?

Olli

It was a requirement from our chimney sweep. Why? The stove is certified + external air supply + recirculation hood but the manufacturer of the controlled residential ventilation cannot guarantee that the controlled residential ventilation will never create a negative pressure greater than 4Pa (chimney or chimney sweep button for temporary shutdown is not enough). Therefore, the chimney sweep wanted to be on the safe side and demanded the differential pressure monitor.