logo about us contact search twitter
maryland home performance with energy star
Home > Improve your home > Duct sealing

icon  Duct sealing

In houses with forced air heating and cooling systems, ducts are used to distribute conditioned air throughout the house. (You do not have forced a forced air system if you have radiant floor heating, radiators or electric baseboards.)

In a typical house, about 20 percent of the air that moves through the duct system is lost due to leaks, holes, and poorly connected ducts. The result is higher utility bills and difficulty keeping the house comfortable, no matter how the thermostat is set.

How do you know that your home has poorly performing ducts?

  • You have high summer and winter utility bills.
  • You have rooms that are difficult to heat and cool.
  • You have stuffy rooms that never seem to feel comfortable.
  • Your ducts are located in an attic, crawlspace, or the garage.
  • You find tangled or kinked flexible ducts in your system.

Benefits of Duct Sealing

A duct system that is well-designed and properly sealed can make your home more comfortable and energy efficient. Properly sealed ducts will also make the air in your home cleaner and healthier to breathe.

Simple Steps to Improving Duct Performance

Because ducts are often concealed in walls, ceilings, attics, and basements, repairing them can be difficult. But, there are things that you can do to improve duct performance in your house.

  • Start by making sure there are no disconnected ducts. If there are, reconnect them with a zip tie or screws.
  • Seal air leaks using mastic sealant or metal tape and insulating all the ducts that you can access (such as those in attics, crawlspaces, unfinished basements, and garages).
  • Never use duct tape. Sealing ducts is ironically the one thing duct tape should not be used for.
  • Make sure that the connections at vents and registers are well-sealed where they meet the floors, walls, and ceiling.
  • Insulate all ducts located in crawlspaces, attics, garages or unconditioned basements to at least R-6.
  • Many homeowners choose to work with a professional contractor for duct improvement projects. The cost for sealing duct work varies greatly based on the required work, but usually costs between $500 and $2500.
Ducts: A series of tubes that circulate air from a furnace or air condition system. These tubes move air from rooms back to the main system. For example, when you turn the thermostat higher, the furnace heats the air and sends it out through ducts into rooms and simultaneously pushes cold air out of the rooms back to the furnace.
Forced air heating and cooling systems: The most common way to heat or cool a home. The air can be filtered and then distributed (forced) through ductwork into your home's rooms through registers.
decrease text size default text size increase text size

find a contractor

Who we are

Your source for certified Maryland contractors for all your home's energy, comfort, health, and safety needs.



Our brochure

MDHPwES brochure


Utility rebates

bge logo

delmarva logo

pepco logo

allegheny logo

smeco logo

Site Home | For Homeowners | For Contractors | Contact Us | Maryland Energy Administration | Sitemap | Last updated: October 8, 2015