My home has a partially-below grade basement that has a "Wave" ventilation system that brings cool, conditioned air in from the main house. The basement has an equipment room containing an oil burning furnace for heat and hot water, which draws fresh air from outside via a wall vent and which is well-sealed from the rest of the basement (by a security door with a rubber gasket).

The issue I am having is that the equipment room has a large amount of wasted space (6ft by 10ft) that I'd like to use for my server/networking/audio gear, but the room is consistently nearly 90 degrees (the furnace heats our water and runs basically 24/7/365).

I would like to open up the room to introduce cool, conditioned air into it, but I am super worried that the Wave fan (which is pretty powerful) is going to instead draw products of combustion/carbon monoxide into the basement living space.

Does anyone have any ideas? I was thinking a fan in the wall to pull air into the room, but then worry that failure of the fan would cause a reversal of the air flow direction and suck out CO.

Here is a not-to-scale drawing. Thanks!! enter image description here

  • 3
    Tell us about the flue-gas setup. Is it naturally vented via a vertical stack all the way through the roof? Commented Jul 4, 2019 at 3:25
  • 2
    Are there any other combustion appliances to worry about, or just this furnace? Commented Jul 4, 2019 at 3:51
  • The furnace is vented through the original chimney, which is located right next to it. And this furnace is the only appliance, it provides hot water for winter heat (baseboard) and sinks/showers.
    – mikewaters
    Commented Jul 4, 2019 at 14:57
  • 1
    How about building a wall to divide the equipment room into two rooms?
    – Mark
    Commented Jul 4, 2019 at 15:28
  • I forgot to include an exterior window there in the diagram. If I built a wall on one side of it, it would be too close to the furnace, and on the other side it would make the space too small to be useful.
    – mikewaters
    Commented Jul 4, 2019 at 16:07

1 Answer 1


You're right to worry that opening up that room to the rest of the basement will mix combustion gases with the rest of the air.

I'm guessing from some clues (oil-fired boiler, baseboard heat) that you're in a cooler climate.

You could cool that space separately from the rest of the house. Can you draw in outside air on a thermostat-triggered vent fan? A/V and network equipment can operate at a higher temperature than we generally keep our homes. 85 degrees generally isn't a problem if there's enough circulation to prevent hot spots.

If it were my house, I would build or install a cabinet to hold the equipment. Use a short piece of flex duct to draw in cool outside air at the bottom. Use another with a thermostatically controlled fan to exhaust it at the top. On the exterior, you would use something like a dryer vent hood to prevent water, bugs, and rodents from getting in. Inside the cabinet, mount a couple additional fans to ensure everything gets adequate circulation.

If the risks of outside dust and temperature swings are concerning, you could do the same solution and vent it into the basement. If you did that, you'd need to make sure the cabinet and all ductwork are sealed tightly (again with the combustion gases). You'd be able to skip the thermostat on the fan as well. But you'd have to listen to that fan whine pretty much all the time you're in the basement. A fan that can move adequate air will make some noise.

  • Excellent idea. Outside temps can be well below freezing, and we get a lot of rain, so my preference would be to vent the cabinet into the equipment room. Does a vent fan with louvers that shut when it powers off exist? I could run that fan constantly, to exhaust the cabinet into the equipment room, and if it fails for some reason the louvers would close prevention reverse air flow?
    – mikewaters
    Commented Jul 17, 2019 at 23:38
  • I would draw air from and exhaust to the same location. Really the cabinet would become, from an air supply perspective, part of either the outside or the basement living space. The sealed cabinet would physically live in the equipment room, but it would breathe the air from the other space. With this design, you don't need louvers or anything, because the air doesn't mix with the equipment room air.
    – CMOS
    Commented Jul 19, 2019 at 1:15

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