What power is required for our fireplace?

Hello everyone,

I’m not sure if I’m in the right place here, but I can’t think of a better "category" for my question at the moment.

In our new house, we would also like to install a fireplace (stove). Primarily, it’s about the "comfortable warmth" during the cold season; it’s not supposed to replace the heating system or be a water-carrying fireplace or anything like that.

Nevertheless, we naturally expect a certain amount of heat to be emitted by the device. You should definitely "notice" when the fireplace is on...otherwise a screen would suffice.

The location is the living/dining room with an area of about 39 sqm, and the kitchen (separated by a large sliding door) about 18 sqm. The warmth should be "noticeable" in these two rooms.

We have already been to the specialist dealer, and the nice gentleman there said that a fireplace with an output of 4 kW would be sufficient for this. Keyword: not too high a kW number, otherwise it gets too hot (or the combustion is throttled down and then the glass gets black).

If I now assume the usual values found on the WWW (1 kW per 10 sqm living space), that would of course be too low in terms of output.

Do you have any experience with this? What do you think?

Best regards

S

Define "new house"....

Newly built or "newly" purchased for you?

In a modern house, I would assume underfloor heating and a fireplace that can be switched on if desired.
That should be completely sufficient.

If I now assume the usual values found on the web (1 KW per 10 sqm of living space), that would of course be too low in terms of power.

You need 100 watts/m2 for an uninsulated 1970s building at -10°. At +5°, to warm up for comfort with such power via a wood stove - you either suffocate or throw all the windows open. Neither is very comfortable ops: For a new building, I would ask the heating engineer which size he would personally choose. 3 or 4 KW will probably be more than enough and could, if necessary, already heat a medium-sized KFW-40 house on their own.

Define "new house"....

New build or "newly" purchased for you?

In a modern house, I would assume underfloor heating and a fireplace that can be switched on as desired. That should be completely sufficient.

Complete new build, with underfloor heating, but none with a specific/special KFW standard. And exactly, the fireplace just "for the coziness." I’m saying, the fireplace installer recommended 4KW. But when I look around, most stoves have 6 or even more KW. That's why I got a bit suspicious whether 4 isn't a bit too little. I’ll just rely on the opinion of the fireplace installer.

The kW values are completely irrelevant. The question is how quickly the stove releases the heat. Install proper storage stones. Then you can easily use 7 kW and more. The stove will then only increase your room temperature by about 2 to 3 degrees.

Yes, that's how I thought it too. However, our desired fireplace has glass on three sides. According to the fireplace builder, the fireplace emits a lot of heat very quickly through these glass surfaces, regardless of the storage stones. They certainly help to keep the temperature somewhat in check and also store heat even after the fire has died down, but the "weak point" in this system is precisely the glass surfaces. Sounds quite plausible to me as a layman.