Fireplace and underfloor heating - is air circulation or storage more sensible?

Good day dear forum,

we have planned a masonry fireplace stove in our new building as a separation between the living room and dining room.


(the planned fireplace extends further into the room, not as in the current plan)

The primary goal is purely aesthetic aspects (fire) and a corresponding feel-good atmosphere. Heating is secondary since we have underfloor heating. Additionally, there is controlled ventilation. I am aware of the cost vs. benefit issue and that it is purely a luxury object.

The room where the stove will be installed is about 50m² with large window areas.

I have repeatedly read about problems of overheating in the rooms when the stove is oversized or if there is underfloor heating at the same time. Opening the window for that does not really make sense.

Now I have received offers from two stove builders who gave me different statements and would build the fireplace differently.
Option 1: 12kW as a circulating air fireplace (draw air in, lead it past the stove and warm it, then release it back into the room) and additionally fireclay bricks for storage
Option 2: 11kW as a storage fireplace with fireclay bricks without any circulating air/air guidance.

Both fireplaces are very powerful at 11 and 12kW? I have addressed the overheating issue with both providers.
Option 1 says that with the air guidance, the room can be heated very quickly if the outside temperature drops and the underfloor heating cannot keep up quickly enough. The storage bricks then release the heat when the fire is out again. If done without circulating air, the fireplace would be ineffective because it takes too long until it gets warm. Overheating would not be a problem.

Option 2 says that the underfloor heating heats sufficiently and therefore the circulating air variant would heat and overheat the room too quickly. The storage fireplace would emit heat slowly and evenly, thereby preventing overheating. The glass pane of the fireplace would release enough heat for short-term needs, so no additional circulating air is needed.

Now I naturally ask myself: who is right or which is the more sensible solution?

Thank you for your assessment and help.

If only appearance, then at most fan-forced heat and preferably no storage stones.

We had a see-through fireplace with more power, but also a 75 sqm living/dining area. Fire on, temperature slightly high (max. +3 degrees in the evening), most of the heat through the chimney. Everything relaxed.

Both fireplaces are very powerful, rated at 11 and 12kW?

Yes, completely!
I am not familiar with this recirculation system, but I hope you can still get something out of my post:

Option 1 says that with the air guidance you can heat the room very quickly if the outdoor temperature drops and the underfloor heating can't keep up that fast.

I consider that nonsense: an underfloor heating system doesn't have to "power up all at once," so it can't keep up or falls behind. It runs continuously with an outdoor sensor, so it always gets comfortably warm.

The storage stones would then release the heat when the fire is out again. If you do it without recirculation, the fireplace would be useless because it takes too long to get warm.

And when do the stones release the heat? Exactly, when you go to bed. (Underfloor heating is not turned off)

Overheating would not be a problem.

Overheating is when you heat a room with too many kW. That is almost always the case with an additional fireplace.

Option 2 says that the underfloor heating would heat sufficiently and therefore with an air recirculation option the room would be heated too quickly and would overheat. The storage fireplace would release heat slowly and evenly, thus preventing overheating. The glass pane of the fireplace would release enough heat for short-term needs; no additional recirculation is needed.

Even in this case, you have an additional heat source in the room that releases more heat than you need at that time.
We have 50 sqm of living space with a large open space to the upper floor. With our 7 kW fireplace, we practically heat the whole house, meaning all accessible rooms additionally. Since the fireplace is operated depending on the situation, you will not intervene much in the underfloor heating, so you cannot avoid briefly ventilating or going out to the terrace if there is too much heat during operation. In your case, the room is also closed—you will open all the doors ;)
What’s the point: the comfort factor makes it warm, and to avoid overheating you have to do something manually. Storage stones might be nice, but they store heat for the night, and you don’t need the additional heat then.
I consider further additional technology for a comfort fireplace to be a waste of money, as well as an oversized fireplace.

Memory stones may be nice, but they store heat for the night, and you don't need the extra warmth then.

But there are worse things than leaning against a still nice and warm stove in the warm living room/kitchen in the morning ;)

But there are worse things than leaning against a still cozy warm stove in the warm living room/kitchen in the morning ;)

Yes, get ready and go to work….

So we have variant two and are very satisfied with it. On the one hand, it is indeed the case that during the transition period the underfloor heating cannot keep up… It simply says outside it’s still too warm to turn on, and when it finally does turn on it needs some time to warm everything up; during this time I, as a woman, have frozen my butt off. Just turn on the stove and that’s it.

I do find the storage stones very useful because they absorb some of the heat and it doesn’t suddenly become 800° in the room.

My father has a normal Swedish stove in his KFW 55 house and you can’t stand it when you turn it on.