How Close Can a Furnace Vent Be to an Air Intake?

Two pipes or openings on the side of a house can look almost identical, but that doesn’t mean the same furnace vent clearance from air intake applies to every installation. That’s where people get tripped up. A furnace vent may terminate near an outdoor-air inlet serving the building, the combustion-air intake for another furnace or … Read more

How Far Apart Should Furnace Intake and Exhaust Pipes Be?

Furnace intake and exhaust pipe separation is one of those things that looks like it should have a simple code dimension. You have two PVC pipes coming through the side of the house—one is the furnace exhaust and the other is the combustion-air intake. So how far apart do they have to be? There is … Read more

How Close Can a Furnace Vent Be to a Window?

Furnace vent clearance from window openings can vary depending on how the furnace is installed. A high-efficiency furnace is often vented through the side of the house with PVC pipe. Sometimes you’ll see two pipes—an exhaust and a combustion-air intake. Other installations may have only the exhaust terminating outside. So how close can that furnace … Read more

What Does “Direct Vent” Actually Mean for a Furnace?

Most people see a high-efficiency furnace with PVC pipe running outside and immediately call it a direct-vent furnace. But what is a direct vent furnace under the IRC? The answer depends on where the furnace gets its combustion air and where the flue gases are discharged. The exhaust pipe tells you where the combustion gases … Read more