Anyone can see if their furnace is on, but would you know if it was venting correctly? Most homeowners overlook this part of their heating system, but HVAC installers for Addario's Services spend a great deal of time running these ports to the outside of your house, because they understand the dire consequences of doing it wrong.

The blue pipe is used for the exhaust port, while the white one is the air intake. The blue pipe is designed to vent harmful exhaust from combustion (like carbon dioxide and carbon monoxide) up and away from the house, as well as away from the air intake of the furnace.

The exhaust port needs to lead outside for obvious reasons, but why does the air intake get the same treatment? Can't you just supply air from inside the house?

You can, but you shouldn't... and here's why:

When you pull air from inside the home, use it for combustion and then vent it outside, you begin creating a pressure imbalance. Eventually, the furnace will have to draw air from wherever it can get it, which in a properly insulated home, will likely be from somewhere gross like a crawlspace, a crack in the wall, or from somewhere that would otherwise be leaking heat outside. What you wind up with is a High-Efficiency Furnace that isn't efficient and clumps of dust and debris being sucked out of the walls and pumped throughout the house. Building an air intake to the outside will eliminate these pressure differences and allow your furnace to run as efficiently as possible. Even if you disregard these issues, most homes in Massachusetts aren't large enough to supply enough air from within the house.

Building these vents/ports may not look like much, but it can make or break your heating system. The next time you're near your furnace, take a minute to check out these ports, and appreciate the part they play in keeping your dwelling warm and keeping your family safe!

For more information on this subject check out www.addarios.com or check out https://healthyhouse.com/articles/iaq... for a good diagram.