Install Fresh-Air Intake Vents on Your Furnace Duct

  • 5-10 hours
  • Advanced
  • 50-500
What You'll Need
One hood for fresh air inlet
Hole saw
Drilling machine
Screws for wood exterior
Caulk for exterior use
Caulk gun
Duct fitting
One Collar for fitting at pipe mouth
Screws for metal sheet joints
Measuring tape
Aviation snips
Crimper for pipe
1 Barometric air damper
Wrench which can be adjusted
1 hanger strap for support
Caulk of silicone
Metallic tape or aluminum foil

The furnace ducts are used for circulating warm air in modern homes. The modern architecture focuses more on raising walls rather than natural openings for the movement of air. This results in the structure becoming airtight and leads to a build-up of suffocating combustible gases inside the home. Fresh air from outside is taken in using inlet ducts. This fresh air is allowed to move out, which then is heated up by furnace to be circulated via furnace ducts.

However, the circulated warm air could become suffocating hence it is a smart choice to install vents for fresh outside air in your furnace ducts.

Step 1 - Choose a Spot for Intake Hood

Choose a place separate and away from any of the furnace, exhaust and dryer vents going into the home. This spot will be the inlet of the fresh air intake hood. A separate entry is necessary to avoid recirculation of suffocating gases.

Step 2 - Install the Hood

Use the hole saw machine to drill a hole. Slowly push the pipe above the fresh air intake hood. Now tighten the inlet hood on the walls of the home using the screws for wood exterior. Use any exterior caulk, should be of high quality, to caulk around the fresh air intake hood.

Step 3 - Create a Hole in Return Duct

Now use the aviation snips to make a 6-inch wide hole inside the return duct. Keep the hole adjacent to the furnace pipe. With the hole in place, install the metallic collar for pipe inside the hole.

Step 4 - Install Duct

Place the galvanized duct between the pipe coming from the inlet lid and collar. Use metallic screws to tighten the joints between duct and collar. If there are any cut joints then use the crimper on the pipe to fit in the joints. Make sure that all the joints are fixed properly or else the fresh air circulation will not work.

Step 5 - Install a Barometric Damper

A barometric damper is installed to prevent any fresh air from entering the duct before the furnace becomes functional. The barometric damper is installed inside the intake hood. Keep the direction arrows of barometric damper directing towards the furnace. It means that the fresh air will flow towards the furnace.

Step 6 - Hang the Duct

The installed galvanized duct hangs using the support of the hanger strap. Be cautious to choose a galvanized hanger strap, which will be higher in tensile strength and against temperature changes.

Step 7 - Insulate the Duct

The final step in this process is making the duct airtight. For this, caulk every joint in the duct. The duct is insulated further using a duct wrap. In this case, the duct wrap used is the foil. It guarantees that the furnace duct will not sweat due to cooler air during the cold season.