HVAC or Roof Leak? How to Spot the Difference

Step 1 - Ask yourself, is it raining?

Is it raining? RoofingSource

It may sound like a silly question, but you would be surprised how many times we receive calls for a roof leak and it hasn't rained in weeks. The water needs to be coming from somewhere and most likely it is from your HVAC.

If it isn't currently raining, then the leak is almost certainly mechanical or HVAC-related. If it is an HVAC leak, what do I do? See How to Fix Your Leaking HVAC below.

The next step is to identify where is the leak coming from.

Step 2  - Identify if the leak is coming from a vent or a stained ceiling tile

The location of where the water is coming from is a great sign of what the cause of the leak and what is going on the roof. If it is a stained ceiling tile, remove the ceiling tile to see where the water is coming from. We often hear "the water is dripping directly out of a silver thing." The big “silver thing” is an HVAC vent.

If the leak is determined to be an HVAC-related issue, you can stop the dripping momentarily by following the steps below.

After a leak is confirmed to be roof-related, please don’t hesitate to report the leak to RoofingSource or give us at (833) 247-ROOF (7663).

Stained ceiling tile RoofingSource
HVAC Vent Leak RoofingSource

How to Fix Your Leaking HVAC

Now is the fun part! You will need to head to the roof! Remember the good thing about an HVAC leak means that you will have it solved in minutes, and you typically do not need to wait for a roofing expert. Troubleshooting an HVAC leak is easy and can be done by a manager.

Fix Your Leaking HVAC RoofingSource
Clean the P-Trap RoofingSource

Step 1 - Clear the P -Trap

The P-Trap is a plastic pipe coming out of the unit. Identify if it is currently draining. If it isn't draining, you will need to unclog it. If it disassembled easily, you can unclog it easily. If it doesn't dissemble, you can unclog it with a wire hanger, a pen, or your finger. Even if it is currently draining, we recommend you still take the time to clean the P-Trap. This important preventative maintenance measure will help alleviate potential future HVAC-related leaks.

Step 2 - Secure the Panel Doors

Are the panel doors closed? Make sure they are properly secured. Keep in mind that just because they might look closed doesn't mean they always are shut. We recommend you tug the doors gently to ensure they are secured.

HVAC PANEL DOOR TEST: Here’s a simple yet effective way to test whether an HVAC panel door is properly secured to the unit. Using a business card or a dollar bill, hold it up against the seam of the HVAC panel in question.
NOTE: This test will only work when the HVAC unit is running.

If the business card falls to the ground, the panel is not allowing air into the unit which confirms that the panel door being tested is properly secured and should not pose any leak risks.

If the business card sticks along a panel seam, the panel door is not properly secured as it is allowing air to be drawn into the HVAC unit. Until all the HVAC panel doors are inspected and secured properly, this suction will draw in water when it rains, thus causing interior leakage from a poorly secured HVAC panel.

HVAC Panel Test RoofingSource

Step 3 - Check the Coil

Locate the coils in the HVAC to check and make sure the coil has not frozen over. If the coil is frozen, the ice is usually melting and dripping down the return air vent.     

Frozen HVAC Coil RoofingSource

Written by

Tom Dawson
Director of National Accounts
(800) 507-3177 Ext. 201

Tom Dawson RoofingSource