I've been doing some sealing and insulating in my attic, and discovered a purpose built vent directly from the utility room into the attic space. See most of these photos

Vent in attic

The house is in a townhome/condo; it is second floor over the garages, so I don't have a basement. The utility room (furnace, water heater, laundry) opens directly into the kitchen. Two registers in the utility room open directly into into the wall space, the top of which space had a vent pipe attached to keep the loose insulation out.

Vent in utility room

Does this make any sense at all? If it does have a purpose, is there a better way to accomplish it than a hole in my ceiling?


3 Answers 3


If the furnace and water heater are gas powered, it would be to provide adequate airflow for their combustion so that you don't get carbon monoxide forming in the utility room.

Here's a link with some information. An excerpt:

The heating appliances are fully isolated from the living space with partitions. Figure 1 provides two vents to the outside, one within a foot of the ceiling and one within a foot of the floor. If vertical ducts are used to bring combustion air to the appliance each vent should be sized at one square inch of free vent area per 4000 BTUH of the appliance input rating.

(This is based on a half-remembered long-ago conversation with a service person working on my furnace and heater, which are in the center of my mostly-unfinished basement: I mentioned framing in a utility room around them and he said not to for that reason).

  • This explains it, but now I need a new question about better ways to accomplish the goal. Jan 7, 2011 at 17:30

Some people still don't understand. There are two vent pipes. One for the gas water heater exhaust that goes through the roof and a separate vent pipe that only runs from the attic vent pipe to the louvers in the wall for gas water heater air intake. The open pipe in the attic is air intake only not exhaust so it was installed correctly.


Looking at your pic, I see a what look like gas lines. The hood above the hot water heater is what is attached to that vent pipe and it goes to the attic so you don't have exhaust fumes entering your living space. In a perfect world this would be vented to the outside of the house, but the attic should be fine to disperse the dangerous gasses.

  • 1
    The hood above the hot water heater goes outside; the vent pipe only passes through the attic. The open pipe in the attic is attached to the wall registers. Jan 7, 2011 at 17:29
  • 5
    This is an old answer, but I had to down vote just on that last sentence. The attic isn't a fine place to vent gas fueled anything.
    – Tim B
    Feb 11, 2013 at 13:28

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