How to Safely Install an Insulated Flex Furnace Duct

What You'll Need
2x4 blocks
Sheet metal Screws
Round Metal End Collars
Metal Tees
Plastic Duct Strap
Foil Tape
Wire shears
Wire reinforcements

The setting up of an insulated flexible furnace duct starts by means of load calculation. It is an automated method of finding out the heat increase or loss for every room on the house. The outcome is a layout design that demonstrates the measurement and position of air channels and register in the house.

Step 1- Create Holes and Cut Out Drywall

Cut the openings in the roofing for the air registers and the drywall should be cut out as well. The registers must be in the middle of the beam space and must be kept around two feet away from the wall.

Step 2- Create a Box

Find the register among the beams in the entry then cut out the drywall for the right measurement filter grille. Nail 2x4 blocks between beams to create a box then a sheet of plywood could be pinned on top so that in can be completely enclosed. Wood is advisable to prevent condensation. Once the openings are slashed, the furnace or air handler as well as the evaporator coil must be put in position.

Step 3- Attach Plenums

Attach plenums into the item using sheet metal screws. One side of the plenum chamber is open and the other one is closed. If there is no central air-conditioning system, a plenum is connected to the opening of the furnace/evaporator loop and this is called supply plenum. Another plenum is connected to the base of the item which is the return air.

After the installation of the plenums, install round metal end collars into the plenums. Those collars let the plenums to be connected to the flexible furnace duct. Cut openings in the plenums and insert the collars. Bend over metal tabs using the fingers.

Step 4- Supply Duct

Supply duct begins in the plenum then put in the metal tees with reducers as they are needed to let the branch channels to be connected. The supply channel would be smaller since more branch channels are connected. The last part of the supply duct would be utilized like a branch channel to provide the register which is farthest from the item.

Connect the flex furnace ducts by thrusting them into the collar or metal tee covering the edge using foil tape. After that, put a plastic duct band around the duct; tighten it with the use of pliers. Cut off the spare band and pull the insulation on the connection then lock it with another band. The insulation must wrap every metal to avoid breaking out in sweat and condensation.

Cut the duct as needed with the use shears to slash the plastic and covering. Cut off the wire reinforcements on the furnace duct using wire shears.

Step 5- Connect the Flex Ducts

Connect the flex ducts to the metal tees, and stretch the cut openings onto the ceiling. Approximately two feet is needed; reduce the duct to size. Feed the edge of the channel throughout the opening in the ceiling then put it out in the space below.

Connect the return air duct with the use of a collar. Draw out the duct to the return air box that initially created. Make a hole above the box, put in the collar then connect the duct. The flex furnace ducts should be out on the beams for proper foundation. They must be held up every five feet. Every metal like the tees as well as the plenums must be insulated.

Step 6- Tape the Registers

Set up the registers into the openings that were slashed in the roofing. Connect the ducts into the registers using tape and bands.

Push up the registers into the openings. Connect the registers by constricting the screws. Set up the return air channel lattice using screws/nails, then put the filter in the item.