I started growing in the sealed room about 7yrs ago. Thats right around the same time they first came out with the glow plug Co2 burner. The glow plug burner was made for the sealed room. The pilot light burner was tested in the sealed room and was considered damaging the plants while the lights were out. Im not sure of the exact resons why but i do remember it was because the pilot light was still burning while the lights were out. Im sure you could add a small exaust to come on while the lights are out. Then your room would be exposed to some things that the sealed room helps to prevent. Sealed room is good for helping to preventing out side smell, blite (powdery mildew), and bugs.