The Importance of Your Furnace and Water Heater Vents

Written by Hanna Plumbing & Heating / November 10, 2020

If your water heater and/or furnace burn gas to heat your water and home, they will also need to expel any byproducts of that combustion (exhaust)— think of the exhaust pipe on your car that removes the byproducts of combustion from your engine. We probably all know that running a car in a closed garage is a bad idea because exhaust (and more specifically carbon monoxide) can be extremely dangerous. Well, the same goes for the carbon monoxide that comes from your furnace and water heater.

So how does your furnace and water heater vent these toxic gases? There are a few different ways to vent your furnace and water heater, but the most common method is called “Atmospheric Venting.” This style of vent will look similar to what is pictured in the image above. This method uses the fact that hot air rises to allow the hot exhaust resulting from combustion to travel up the vent duct and escape from those vent chimneys on your roof. There is also “direct venting” where the vent duct connects to the wall and pushes the exhaust directly outside. “Power venting” uses an exhaust fan to pull the exhaust up and out of your home. The nice part about atmospheric venting is that it’s very simple, which means fewer parts that could break down. But there are still a few things to keep an eye on.

Carbon monoxide is odorless, so having a carbon monoxide detector where your furnace and water heater are located are important for making sure this exhaust is being vented correctly. When the exhaust isn’t being vented and builds up in your home it’s called “backdrafting.” There are a number of reasons this can happen:

• Poor vent design or installation— Because carbon monoxide is toxic, it’s always a good idea to make sure you have a professional with a good reputation and experience installing or at least inspecting these vents.

• Vent hood is misaligned or not large enough— The vent hood is the conical shaped piece that helps funnel the exhaust into the vent. If this vent hood isn’t large enough or is misaligned, it’s likely that the exhaust is escaping into your home.

• Damage to the external chimney that is intended to release these gases outside of your home— After storms or even just years of exposure to the elements, the chimney vents on your roof can become damaged and prevent exhaust from escaping as it should.

If you feel confident checking the vent hood and installing a carbon monoxide detector, those are things most homeowners should be able to do themselves. However, it’s not a good idea to try and install a vent duct yourself, and you probably will want a professional to get on your roof and inspect your chimney vents. Chimney vents are tricky, if they are damaged they could be releasing exhaust into the crawl spaces of your home, which makes it much more difficult to detect and to determine where the carbon monoxide is coming from.

Carbon monoxide is too dangerous to mess around with. If you have concerns about your exhaust vents or you’re just looking for peace of mind, give Hanna a call at (319) 377-2809 or contact us online.