Can You Change the Size of Heating Ducts?

Initial Duct Installation

• Typically, workers install heat ducting during a building's construction process without any official design considerations. Building designers do not commonly document ducting placement within an architectural blueprint. Contractors must decide on the best duct placement and size the ducting with the original heat source. Unfortunately, the duct placement may not be the most energy efficient. Typical installations route duct work through crawlspaces and attics, making it difficult for repairs or maintenance.

Size Change

• Changing the heating duct sizing is commonly performed when replacing the heat source, such as purchasing a larger furnace for more heat output. However, the building's overall final construction determines the amount of labor involved for physically accessing the duct work. Basements and attics that are unfinished or have open wood framing are typically easier to handle for duct size changes. Workers can maneuver within the crawlspaces and switch the duct work. However, buildings will finished basements and attics are much more difficult to access. Finished areas usually have sealed walls of drywall or brick. These buildings would require extensive remodeling techniques for accessing the hidden duct work, generating a costly invoice.

Benefits

• Changing the heating duct size to match the heat source has many benefits. Duct work that is too small for a heat source limits the heated air's movement, causing the heat source to work harder and shortening its overall lifespan. Oversized duct work may disperse the traveling heat, causing it to cool and enter the receiving rooms as cooler air than intended. As a result, the heating system will cycle constantly for achieving the correct temperature level, shortening the heat source's lifespan.

Leaks

• Ducts tend to leak forced air at their connection points. Changing the duct size will also force the installer to seal the new ducts, improving heating ability throughout the building. Any leaks within the system forces the heat source to exude more energy for more heating air. New duct work from a size change will renew the heating system's energy efficiency. After changing the duct size, any leaks that may occur in the future can be sealed by a professional contractor.