HomePool Designer, Outdoor Living Landscape Architect BlogBack


Soffit Ducting part 2 in a 3 part technical series

Pool Design article by Kevin Ruddy, SWD Master


  • Use when it is not possible to supply the air low and return high.
  • The supply air grill must be located close to the windows, preferably within twelve inches from the surface.
  • Direct 80% of the supply air down the walls with the remainder directed along the ceiling to break up any stratification and stagnation occurring near the ceiling.
  • Airflow should never be directed over a pool surface since this leads to bather discomfort and excessive evaporation.
  • Flood skylights with supply air through ducting, or use ceiling fans as an alternative if ducting is not available.


  • Supply air ducts must be located below grade around the inside perimeter of the enclosure for low set windows and sliding glass doors.
  • Ducts should be constructed of a non-corrosive material such as PVC or galvanized steel.
  • Linear slot diffusers must be positioned to blanket the glass surfaces and outside.
  • Below grade ducting prevents the migration of cooler air down the wall and across the floor, reducing the incidence of cool dead air spaces that may form on windows or walls

  • Vapor barriers should be installed immediately behind the interior wall surface.
  • The dew point must be reached on the cold side of the vapor barrier where moisture is not present.
  • Always seal barrier joints around switches and receptacles to prevent localized moisture migration.

The next segment in this series will be published next week.

Kevin Ruddy

Kevin Ruddy

Omega Pool Structures, Inc.
2091 Church Rd.
Toms River, NJ 08753
T (732) 255-0231 F (732) 255-2883