Skip navigation

Serving Northern California Since 1946

Serving Northern California Since 1946


DeHart Plumbing, Heating, and Air Inc. Blog

How Do Duct Leaks Start in the First Place?


Our top concern with our customers is helping them enjoy the best energy efficiency for their home so they can “Live Green, Save Green!” One of the major sources of energy loss in homes comes from ductwork leaks in the HVAC system, and unfortunately, this is a problem that’s easy to escape homeowners’ notice for a long time. 

We’ve previously written about how you can detect duct leakage in your home, and in this post, we’ll address another question about this problem: Why do duct leaks start in the first place? 

Poor initial installation

Here’s an unfortunate fact about the ductwork in homes: most of it was poorly installed. It’s often one of the last parts of a house put in place during construction, done almost as an afterthought. This means the duct designs contain too many bends and turns that place extra strain on the material, as well as poor connections that decay fast. These ducts might start to leak after only ten years or so. Duct sealing can help with this, but in some cases upgrading the ductwork may be the best choice.


Ducts, like any part of a house, age. The years of strain placed on them will eventually lead to sagging that can cause gaps to open between sections. Poor initial design (see above) can also contribute to age damaging the ducts.

High humidity and heat

Ducts installed in places that have high heat levels will decline faster than others. High humidity is also a concern since it leads to corrosion and water damage that will rapidly cause air leaks in the material. 


Not a pleasant thought, but infestations of insects or rodents are a frequent cause of leaking ductwork. High humidity can draw both. Solving problems with animals and other vermin in the ducts requires the work of both HVAC specialists and pest control—this is definitely a double problem you want to take care of as soon as possible.

High air pressure

If the air pressure inside the ducts is too high, it can lead to holes. This increase in air pressure can come from several sources (once again, poor design is a common cause), but one problem that’s easily avoidable is blocked air vents and faulty zone control systems. The reason we never recommend trying to seal off heating or cooling to rooms by blocking or closing vents is that it leads to troubles like this.

Construction damage

If you’ve had remodeling done in your house at some recent point, the construction may have accidentally damaged the ducts and created leaks. 

Regardless of what caused your ducts to begin leaking, it will create a dent in your HVAC system that will waste energy and also affect cooling and humidity levels around the house. Getting started solving the problem isn’t difficult: you can call us for duct testing and duct sealing in Modesto, CA. We aim to make your home a lean, green, and energy-efficient machine.

Call Greenhart today if you think you may have duct leaks in your HVAC system. Live Green, Save Green!

Comments are closed.