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Experiencing Higher Heating Bills? Check The Plenum For Leaks And Learn How To Eliminate Them

If you’re electric or gas bill is more expensive than usual, but you haven’t been running the furnace more than normal, there may be a problem with the supply plenum. This part of your furnace is attached to the ducts via joints that can sometimes leak. Use this guide to determine whether there is an air leak at this joint and then fix the problem.

Step 1: Gather Your Tools

Go to the home improvement store and pick up the following tools:

  • foil tape
  • smoke pencil
  • stepladder
  • utility knife
  • latex gloves
  • duct mastic

Note: Some homes have a lower supply plenum that is easy enough to reach without a stepladder.

Step 2: Test the Plenum Joints

Turn the furnace on by turning up the thermostat, and then locate the plenum joint; use the stepladder to reach it if necessary.

Hold the smoke pencil near the joint, and use it to place marks on the wall or on the joint itself where you see the smoke from the pencil. The location of the smoke will show you where the air leaks are.

Step 3: Turn Off the Furnace

Go back to the thermostat and turn the furnace off. Then allow the plenum joint and the ductwork to cool completely. This might take a little while.

Step 4: Apply the Duct Mastic

Put on a pair of latex gloves, and dip your fingers into the duct mastic. Smear the mastic liberally directly on the joint, where the pencil marks indicate the leaks are.

Step 5: Apply the Foil Tape

Cut strips of foil tape with the utility knife, and then pull off the backing of the tape. Then attach the tape to the joint seams on the plenum and duct work.

Press the tape around the joint so that it contours and gives the appearance that it is not there.

Step 6: Test the Plenum Joint

Turn on the furnace at the thermostat again, and test the joint with the smoke pencil once more. If there are still leaks, turn the furnace off and allow it to cool. Then repeat the mastic and tape process again.

Call your HVAC professional, like at Affordable Group Inc- Heating & Cooling Specialist, if you have any problems with these steps, or if you simply cannot get the leak to go away. Ask them about other troubleshooting tips should you experience high electric or gas bills in the future. Share this with others who might be a little perplexed about their energy costs.

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