Furnace vents net to sandbox. Is this bad?

April 26, 2008 9:50 AM

High-efficiency gas furnace installed where previously there was mid-efficiency. So it vents straight out the wall while the old furnace used the chimney. The vent is right next to the sandbox. How bad is this?

Tiny yard -- not much other space for the sandbox. It's either keep it or get rid of it.

Of course, during the peak months for sandbox usage, the furnace is rarely used.

It's in a corner (between the house and the wooden fence) so a little more enclosed than if it were in the middle of the wall.

The kids are 4 and almost 2.

A sandbox is one of their favourite things in the world and they can use it for hours at a stretch.

posted by winston to home & garden (5 comments total)

Is it possible to have the vent pipe extended away from the sandbox once it exits the wall?
posted by R. Mutt at 9:56 AM on April 26 [1 favorite]

I can't imagine it's a good thing for them to be next to it when it's running--the two main concerns would be the heat from the exhaust, and carbon monoxide. (I'm not sure if either one is definitely a risk, but they both seem likely.) I don't think it's much of a big deal when the furnace is off, though.

Have you looked into extending it? It might be possible to put some of that double-walled steel piping to basically carry the exhaust up along the wall, so it actually comes out above their heads. Since the exhaust is warm, it'd rise, and it would probably take care of any risks.
posted by LairBob at 9:58 AM on April 26

One of the things with the high efficiency furnaces is that the exhaust isn't very hot at all, that's why they can vent out the side. You'd have to check with your hvac contractor whether those vents even can be extended.

The carbon monoxide issue is slightly more worrisome, but I wouldn't worry too much, as you said, heat use and outdoor play time are almost mutually exclusive. On the rare times both occur at the same time I would expect that the wind would solve the problem.

Probably the best solution would be to just turn off the heat for the rare times that happens.
posted by gjc at 10:06 AM on April 26

I have a Buderus super-high efficiency gas system which direct-vents, and my understanding is that most of the outflow is water vapor. However I don't have a lot of info about how the limited amount of CO2 that comes out would affect someone right next to it and breathing it in, let alone a kid.

I'd suggest you look up your furnace on the manufacturer's site (here's mine) and get the specs. Then you'll be able to research specific CO2 loads.

It certainly won't be a problem while you're not running the system. (Mine does hot water too so it goes year-round.)
posted by miss tea at 10:19 AM on April 26

Thanks everybody
posted by winston at 10:16 AM on May 3