Energy Efficient construction

Benefits of locating ducts within the building thermal envelope;

• Improved comfort. Ducts within the conditioned space or thermal envelope of the building can deliver conditioned air better at designed temperatures. That means a more consistent level of comfort in the house and quicker recovery with the use of a set back thermostat.
• Improved indoor air quality. Ducts located in the attic, basement or crawl spaces can draw dirt, dust mold, radon gas, and other pollutants into the house through leaks in the return air ducting. By locating the return duct within the building envelope, only indoor air will be drawn in through leaks and the amount of airborne pollutants will be reduced.
• Lower utility bills. The air ducts are typically insulated, but running conditioned air through the ducts will result in heat lose or gain in the conditioned air depending on the season. Older R-6 ducts and newer R-8 ducts help insulated the conditioned air, but running that air through a 160 degree attic is always going to result in energy lose and higher utility bills.
• Lower equipment cost. Ducts located within the building envelope can be sized smaller. This makes the HVAC equipment less expensive and easier to install in floor and wall cavities. The furnace and cooling equipment can be sized smaller and the equipment will run shorter times. Both can help lower your equipment cost.

Jim Hemsell

www.Professionalinspector.com