← All blog articles

Water Stains Around Your Ceiling Near the Vents? Here’s Why

August 24, 2015

The usual suspect is that condensation is forming on your air ducts and leaking onto your ceiling.

The condensation forms because hot, humid air is coming into contact with cold air ducts. It’s just like how droplets form on a glass of cold water on a hot humid day.

Clearly, you don’t want to ignore this. Well, not unless you want to pay to fix expensive water damage or to get rid of the eventual mold growth.

Here’s what’s causing this issue and how to fix it.

3 causes of condensation on air ducts (and how to fix them)

1) Under-insulated air ducts

The problem: Warm, humid attic air is hitting the cold AC duct, creating condensation and causing the water to run down the ceiling.

The solution: Wrap the attic ducts with air duct insulation.

Related: 5 Traits of Highly Efficient Air Ducts

2) Under-insulated duct boot

The problem: The duct boot, the metal connector between the air vent and your air ducts, gets cold, causing water to condense on it and drip down your ceiling.

The solution: Insulate the boot, if possible, by surrounding it with fiberglass insulation.

3) Air leak around the duct boot or vent

The problem: If the boot isn’t properly attached/sealed to the duct, then cold air escapes, mixes with the moist air and condensation forms. And, well, you know the drill. Water drips down to the ceiling. The issue could also be with a leak between the air vent and the drywall.

The solution: If the leak is between the boot and the duct, it should be sealed with mastic sealer. If it’s between the register and the drywall, you can seal the leak using caulk. If you can’t find the leak, call a professional air conditioning company for help.

Live in Florida? Need help today? Call Cool Today!

Cool Today provides award-winning air conditioning service to Sarasota, Florida and the surrounding areas like Bradenton, Tampa and Port Charlotte. If you have any questions, talk to one of our experts for help.