Learn all about your HVAC and how to install an air supply line and cold air return with this guide.
Things You’ll Need:
- sheet metal and sheet metal screws
- self-tapping screws
- rigid and flexible duct
- ceiling register boot
- plastic cable ties
- starter collars
- round duct cutter and sheet metal circle cutter
- right-angle drill
- safety goggles
- power nut driver
- screw gun and drill
- tape measure
Understand Your HVAC
A HVAC works to heat your home in cool weather and cool it in warm weather. A fan works to draw air from the house through the system so that it can be either heated or cooled, depending on the room temperature. When the weather is cool, gas burners create heat within the heat exchange and this then heats the air that is circulating through the system. The warm air flows through the plenum and to the supply trunk line, where it is then distributed through the air vents through the home to heat rooms as needed.
When the weather is warm, cooling coils within the plenum cool the air flowing through the system before redistributing the cool air throughout the house.
Note: if you’ve added a new room to the property, you might need a load calculation to make sure that the furnace is big enough to supply the new room with the cool or warm air.
Attach the Takeoff to the Supply Line
- Check to see if you need a permit before embarking on any heating or cooling project.
- Using a pencil, mark the centre point of the takeoff and using the hole cutter and the cutting bit, drill a pilot hole.
- Next, pre-set the cutting bit so that it sits at the correct diameter to prevent cutting a hole of the wrong size. Put the centre guide into the pilot hole that you drilled earlier and then carefully start the cutting bit along the inside of the pilot hole to create a perfect circle. Using a right-angle drill will help here as the space that you’re working in is relatively small.
- Once the takeoff is set in place, pull the tabs over so that it will be fastened securely to the duct.
Install the Ceiling Register Boot and Cut the Supply Duct
- Put the ceiling register boot between the floor joists and screw into place using the power nut driver and the self-tapping screws. Measure from 1 inch into the takeoff to 1 inch into the boot collar to work out how much supply duct you’ll need to cut, then cut it to length using the round duct cutter.
- Fit the duct together and snap into place.
Install and Secure the Damper
- Making sure that you’re installing the damper to the bottom of the duct, install it by drilling a hole into the side of the duct and then screw the damper into place onto the duct. Put the crimped end of it in first and then put the other end of the duct in – the takeoff will rotate, allowing you to get a tight and secure fit.
- Secure both ends of the damper and ducts by screwing sheet metal screws into the collar.
Add the Register and the Support Brackets
- Add support brackets to keep everything in place along with the register to finish the job.
Install the Cold Air Return
For the furnace to work properly, the air needs to be recirculated through the system and so that is why a cold air return needs to be installed.
- Nail a piece of sheet metal onto the back of the stud cavity and cut one hole in the stud cavity and another in the existing cold air return.
- Secure start collars through both of the holes and then use the non-insulated, flexible duct to connect the two holes. Secure the duct in place with the plastic cable ties.
Source: DIY Network