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Have you ever noticed uneven temperatures in your home or higher-than-usual energy bills?
One often overlooked culprit might be a broken seal around your AC plenum. While it may seem minor, a compromised plenum seal can reduce efficiency, increase energy costs, and even impact indoor air quality.
Let’s understand why this happens and how you can fix it.
Why Plenum Seals Break
The supply and return air plenums are the large boxes that distribute air throughout your home. Seals can break for several reasons:
- Expansion and Contraction – Heating and cooling cycles cause the metal to expand and contract repeatedly, which can wear down old sealant.
- Aging Materials – Sealants and tape can simply degrade over time, losing their effectiveness.
- Poor Installation – If ducts were not properly sealed or fitted initially, leaks may develop later.
- Physical Damage – Accidental damage from home projects or pests can also compromise the plenum seal.
Signs Of A Broken Plenum Seal
How can you tell if your plenum seal is failing? Look for these signs:
- Higher Energy Bills – Leaks force your HVAC system to work harder, driving up costs.
- Uneven Temperatures – Some rooms feel warmer or cooler than others because air escapes before reaching all areas.
- Poor Airflow – Weak air pressure from vents can indicate leaks.
- Excessive Dust -Leaks can pull dust and allergens from unconditioned spaces like attics into your living areas.
How To Repair A Broken Plenum Seal
- Locate The Leaks
Visually inspect seams and connections while the system is running. Use plastic on registers to pressurize the ducts or a smoke pencil to make leaks visible.
- Prepare The Area
Turn off the power at the circuit breaker for safety. Clean the plenum and duct surfaces, removing old sealant or debris for a strong bond.
- Apply New Sealant
Use a combination of UL-rated aluminum foil tape and fibrous duct mastic for a long-lasting fix. For larger gaps, embed fiberglass mesh into the mastic for extra strength.
- Insulate
Once cured, wrap any exposed ductwork in unconditioned spaces with insulation to maintain airflow temperature and prevent condensation.
When To Call A Professional
If the damage is severe, inaccessible, or involves flexible ducts, it’s best to call a certified HVAC technician. Professionals can provide a permanent repair that ensures efficiency and safety.
Properly sealing your AC plenum can improve comfort, reduce energy costs, and extend your system’s lifespan. Trust Scottsdale Air Heating & Cooling to inspect and repair your ductwork for optimal performance and peace of mind.
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