Fireplace stove, independent of room air

We are also currently deep in this topic (fireplace, controlled residential ventilation) as well as the preparation and gathering of information.

We are aware that we will not be able to avoid a pressure switch, but that is not the question.

This is not clear to us, for example. We actually do not necessarily want to have a pressure switch in the house. Can one generally say, controlled residential ventilation (regardless of central/decentral) + fireplace (regardless of dependent/independent of room air) => requires a pressure switch? We thought it primarily depends on the range hood, since it tends to "suck out" around 600-800 ccm/h, and since we will decide on a recirculation hood here (and also a room air-dependent fireplace), in our opinion a pressure switch is not necessary.

I am open to clarification, since of course I only have half-knowledge in this area.

With a room air-dependent fireplace, you would not have the issue of a cold source related to the supply air pipe either.

That primarily depends on the chimney sweep. Controlled residential ventilation + chimney almost always means that a pressure monitor is necessary. It was the same for us; despite a recirculation hood and a certified chimney, we needed the pressure monitor.

Supply air from the flue is always a bit of an issue according to my chimney sweep - first of all, the flue is expensive and often it doesn’t work very well - depending on the chimney and flue length.

I have a supply air pipe that opens into a small light well - you get a thermal bridge with that, but honestly? I don’t care - I won’t die or overheat because of it. If necessary, you can also install an automatic combustion control that closes the supply air duct...

Insulating the pipe is only important if it runs through a heated room.

We also have to have pressure sensors - but I don’t find that bad. It saves you the trouble and cost of a [DIBT]-approved chimney.

We are also planning a central ventilation system with heat recovery as well as a room-air-independent fireplace on the ground floor with supply air in the chimney jacket.

Has anyone had experience with installing a sauna heated with a wood stove in the basement in addition to the above-mentioned technology?

My idea is to lead the exhaust air of the wood stove into the same chimney. Most likely, however, a separate duct will be required. Accordingly, the chimney will be quite large across all three floors. An alternative for me would be to forego a wood stove and install an electric sauna.

Hello dear community,

In recent months, I have also dealt with the topic of house construction. After all, we moved into the house in late summer. The house is a Kfw 70 house with a gas condensing boiler and controlled residential ventilation with heat recovery.

We also decided on a fireplace. Finally, a combustion air supply was installed under the foundation slab with a 200mm KG pipe. A corresponding shaft was installed on the exterior facade. The connection of a fireplace is planned for the coming year.

Due to the weather conditions in recent days, it repeatedly happened that the shaft was filled with water. The water also flowed into the corresponding supply air pipe. At first, I suspected the inflow was caused by rain. However, when I removed the water and checked again the following day, I noticed the water level had risen again. I noticed that the shaft itself is not closed at the bottom. My suspicion is that the water is being pressed in from below.

I am now interested in an expert opinion regarding the installation of the supply air pipe itself before I confront the builder with the problem. How can the problem be solved? What seems strange to me is, on the one hand, that the pipe leads outside without a flap, etc., and of course the water issue.

Thank you in advance for your feedback.

I have added 2 photos as attachments.

Best regards

If water is pressing from below, you must extend the intake air pipe upwards out of the water hazard area with a 90° bend (not arbitrarily long, the lengths are limited. Ask the chimney sweep). The cross-section must not be reduced (probably the shaft will have to make way).

For a separate intake air pipe in DN100, the maximum pipe length is about 3m. These details must be agreed with the district chimney sweep before construction.