Guide to Energy Efficiency 4 - Sealing Your Ducts Guide to Energy Efficiency 4 - Sealing Your Ducts
Ducts are an integral part of a forced-air system suchas a furnace, heat pump, or central air conditioner, whose job is to circulate heated or cooled air evenly to every room in a house.
Poorly performing ducts can leak conditioned air and reduce your system's efficiency by as much as 20 percent, by causing it to work harder to keep your home at a comfortable temperature. Ducts are commonly concealed in walls, ceilings, attics, basements, or crawl spaces, which can make them difficult to access and repair. EPA recommends using a professional contractor for duct improvements. Many contractors who install heating and cooling systems also repair ductwork. For tips on selecting the right contractor, see "Working with a Heating and Cooling Contractor."
Improve your ducts by sealing leaks and insulating the ducts in attics and crawl spaces. This will improve your system's overall performance and your homes's comfort and indoor air quality. You should have your duct system checked by a professional contractor to ensure it is operating efficiently to deliver the right amount of air conditioned air.
Duct Improvement Checklist
When making improvements to your duct system, your contractor should:
- Check, measure, and identify leaks with diagnostic equipment.
- Repair or replace damaged, disconnected, or undersized ducts. Straighten out flexible ducts that are tangled or crushed.
- Seal leaks and connections with mastic, metal tape, or an aerosol-based sealant. Duct tape should never be used because it will not last. Test airflow after sealing ducts.
- Seal all registers and grills tightly to the ducts.
- Insulate ducts in unconditioned areas, like attics and crawl spaces,with duct insulation that carries an R-value of 6 or higher.
- Include a new filter as part of any duct system improvements.
- Conduct a Combustion Safety Test after ducts are sealed to ensure there is no backdrafting of gas or oil-burning appliances.