We just built a room addition in our house, a new bedroom for my kids (ages 4 yrs and 7 months).
The 4 year old slept in his new room for the first time last night, and when I went to check on him, I noticed that when I opened the door, there was a little resistance to it. That is, air resistance. Obviously not nearly enough to keep my from opening it, but there’s a little escape of air when I do open the door.
Also, the room is noticeably warmer than the rest of the new floor. It’s smaller, it has its own a/c vent, the window is brand new and very energy efficient (rest of the house has older windows). The warmth is good, means the insulation is working.
But it made me think…is there a chance there’s no enough circulation in the room? If the air doesn’t circulate enough, can that cause a significant decrease in available oxygen levels? I’m even more concerned when I think of a 7 month old baby joining his brother in the room.
So I realize this is either a serious issue… or I’m an idiot who doesn’t know the first thing about construction. And this is me, less afraid of being and idiot than of being right.
Do I need to worry? Or is this just a well insulated room?
My daughter’s room does this as well when the furnace fan is running. As far as I can tell, it just means the furnace fan is pushing more air into the room then the return is pulling out, therefore creating pressure and pushing in the door. I wouldn’t be the least bit worried about it.
I suppose it’s ever so slightly possibly that the kid’s room is perfectly balanced and the rest of the house is under a slight vacuum when the furnace fan is running which would also make it hard to open the door.
Either way, I wouldn’t worry about it.
If you are worried, all you have to do is go into his room and shut the door while the fan is running, if you feel air entering the room through the duct, then there’s circulation and the oxygen levels are going to be the same as they are in the rest of the house.
If you are concerned about it, installing a vent above the door to allow better ventilation is a do-it-yourself project that likely wont even take your entire afternoon.
That said, it’s not uncommon at all for one area of a building to have a different air pressure than another part. Ever walked into a grocery store and felt the “wind” blowing from inside the store out the door?
Then make sure to get another one to keep in an open area.
Keeping a CO detector in a closed room will keep him safe, but leave the rest of you unprotected. The only thing you’ll be protected from with a CO detector in a closed room is a cracked heat exchange, but not other things like flue gasses backing up into the house, car exhaust coming in from an attached garage or problems with any other gas appliances.
Another possibility is that the ductwork to the new addition is larger or more efficient than the old ductwork in the rest of the house, so more air from the furnace fan is going there. To fix this, there are usually dampers in the ductwork that you can adjust to reduce the amount of air going to that room, or you could simply close the heating duct in the room partway.
Assuming you want to do this. For a child (especially an infant), keeping that room a bit warmer during the winter may be a good idea.
I don’t know of any home furnace capable of causing such a drop in air pressure as to deprive a person of needed oxygen. That’s what is being asked here and not if there is a carbon monoxide leak. The room ducts are just not of equal capacity for in and out.
This sounds like the question we get her occasionally of people dying from a fan running in the room, which seems to be a South Korean paranoia.
Well I don’t think there’s an out vent in the room at all. Just the in vent. I’m most concerned about the infant as one thought behind SIDS is that babies sometimes breathe in their own carbon dioxide and aren’t strong enough to handle it at such a young age.
But I think adding a small vent over the door is a good idea for circulation in general. Contractor is still doing finishing touches and can add this easily.
Fuggedaboutit. The oxygen level in the room will equilibrate to the outside level unless you put a lot of work into stopping it from doing so.
I inferred that the door opens into the room, and that you were pushing against an over-pressure, right? Then to quell your worry, go into the room with the central air or heat running. Close the door and make sure you’ve got that air-pressure tension on the door if you try to open it. Now go over to the vent and put your hand in front of it. Feel any air coming out? (If not, you might try closing the vent a bit to increase the air stream’s velocity… or licking your finger to better feel any slow, laminar air flow.) That exact amount of air entering the room through the vent is leaving the room somewhere else. This shows two things: (1) there is new air coming in, and (2) there are “cracks” in the room through which oxygen levels could equilibrate even in the absence of fresh air coming in.
(And, indeed, retail CO detectors do not report O[sub]2[/sub] levels and are not relevant to this issue.)
There is definitely air coming in through the vent so that would mean air is getting out somehow. Would have to be through the closed door (well, around the edges), at least the majority of it. Only other in/out is the window, or has to travel through walls otherwise.
So is even small amount of air circulation sufficient? Even when they are both teens?
I know I’m beating this to death but I want to make sure I do this right. Downside of adding a vent is noise. Small tradeoff for air, but would prefer not having it if still safe.
I think this is a good reason to install a transom. Not so much to ensure sufficient oxygen, but because in the right situations, transoms are so fucking cool.
(You will eventually have to install a fog machine and a lamppost in your yard, but that’s another thread.)
Can you just leave their door open? At least until the baby is old enough that SIDS is no longer a concern. (I though 7 months was long past the typical SIDS risk point, though)
I don’t understand what you’re asking. There is air pressure on the door - that means the room is at slightly higher or lower pressure than the rest of the house, and so air is definitely moving either into or out of the room. If the difference was pronounced enough for you to notice it, then the air circulation is definitely adequate.
If you are really worried, just get a fan and set it to oscillate.
