Conditioned Space Attic

Attic hvac systems save space.

Conditioned space attic. The acceptance of unvented conditioned attics continues to grow among builders and building officials. 1a attic access door. If there is a desire to make that space conditioned to protect stored belongings if moving everything out to air seal and insulate at the attic floor would be a hassle and or if insulating at the attic floor would remove storage space then insulating at the roof line is a better option. If the air distribution is in the attic space then consider insulating the rafters to move the distribution into the conditioned space.

Most contractors would never consider installing uninsulated ducts in a vented attic or crawlspace but regularly do in basements and foamed attics. In unfinished attic spaces insulate between and over the floor joists to seal off living spaces below. Among the early promoters of conditioned attics was joe lstiburek a principal of the building science corporation. Code requirements vary across the country.

A common idea promoted across the industry is that any heat lost from an uninsulated duct system to a conditioned space isn t truly lost and has no effect on energy consumption. Unvented conditioned attics were quite rare before the 1980s. Is the attic used for a significant amount of storage. The roof deck in an unvented attic must be exceptionally airtight.

Low efficiency gas appliances that are prone to spillage or backdrafting are not recommended in this type of application. Ducts in conditioned space details figure 1 vented and unconditioned attic. The air handling unit is located in a conditioned basement. Heat pumps heat pump water heaters or sealed combustion furnaces and water heaters should be used.

Lstiburek s enthusiasm was rooted in his desire to bring attic ductwork inside a home s thermal envelope. Most updated central air conditioned homes have a new air conditioner split system meaning the ac is broken up into parts. An outdoor unit which houses the fan condenser and compressor and an indoor unit which holds the evaporator and fan. Making the attic a conditioned space taking the building envelope to the roof is a good approach and will save energy another approach is to use radiant coated deck sheathing seal all ceiling attic penetrations and blow in r 60 insulation as it will cost less than spray foam and should give at least the same energy efficiency to the home.

Well mainly it s a way to save space. The irc has permitted unvented conditioned attics since 2006 with certain requirements.