Vertical exhaust pipe clearance near side entrances and air returns
Routing exhaust pipes vertically near side entrances or placing cold air returns close to heating appliances raises the risk of pulling unwanted gases back into the house. Homeowners are left guessing whether specific measurements—such as maintaining 3 feet of clearance or being 5.5 feet away from a furnace and hot water tank—meet safety standards.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
- 1Putting the pipes vertically or checking local code requirements.
- 2Asking online forums for advice
- 3Relying on contractor installation standards
- 4Checking equipment modulation and fan speed settings
In their words
Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.
“my dad and I has been trying to do stuff around the house and our side entrance has some exhaust that protrudes, and i did some research and it said that there needs to be at least 3 feet of clearance, and my dad wants to put the pipes vertically, is there any issues that might come up from him putting these exhaust vertically?”source ↗
“They added this cold air return very close (~5.5 feet) to our high efficiency carrier modulating furnace and hot water tank. Is this too close and at risk of pulling in unwanted gases from furnace and heater?”source ↗
Where this came up
People with this problem also raised
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- 2How to get the right slope on a garbage disposal pipe
- 2How to route a plumbing vent offset around obstacles