Pay Attention To Ductwork Design When You’re Renovating

Ductwork design during a renovation project is both a challenge and an opportunity. Adding on to an existing system may involve mating two different design configurations, duct sizing and heating/cooling equipment. On the other hand, a renovation offers the opportunity to correct errors of the past.

In previous eras, duct design and construction did not occupy a high priority in residential construction. Instead, it was regarded as a chance to cut costs. Many residential duct systems were not even constructed to last the life of the home. When renovating a home, more efficient design can be incorporated into new ducts and improvements may be made to existing ductwork, too.

• Design the system to remain within the conditioned area of the home. Ducts routed through unconditioned attics or crawl spaces suffer a thermal loss due to acute temperatures. If ducts must pass through unconditioned zones, use insulated ducts that meet the standards of the 2000 International Energy Conservation Code.

• Use only hard ductwork. Don’t utilize wall voids or channels between studs as replacement return ducts instead of proper metal ducts—a common practice in previous eras. Replace any existing improper ductwork with approved hard ducts.

• Reduce the length of duct branches by placing supply vents of new ducts near interior walls.

• If the duct system utilizes a central return, include a return on each floor of a multi-story home. Also install transfer grilles or jumper ducts between rooms to provide an unobstructed air path to the central return. If possible, install a dedicated return in each room that has a supply register.

• Seal all duct joints with flexible mastic sealant, then mechanically fasten the joints with sheet metal screws. Make sure an HVAC contractor pressure tests the ducts to determine if the degree of air leakage relative to total system airflow is within specifications.

Sobieski Services provides professional ductwork design and installation for residential renovation.

Our goal is to help educate our customers in Delaware, Pennsylvania, Maryland and New Jersey about energy and home comfort issues (specific to HVAC & plumbing systems).

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