Supply Duct Layout Unvented Attic

The two categories essentially are the demarcation between regions where cold weather conditions occur with sufficient frequency and intensity that sufficient moisture accumulation from interior sources can occur on an uninsulated roof deck to risk mold corrosion and decay problems.

Supply duct layout unvented attic. Although both the attic floor and the ductwork are insulated ted recognizes the situation isn t ideal. Unvented attic design falls into two categories. Up against the deck may be the worst place in the attic to. This material focuses on placing the ducts within the conditioned space.

The 1 800 square foot brick ranch in climate zone 4 dates from the 1960s but the previous owner installed both a furnace and ductwork in the attic just four years ago. Fully ducted systems are the most efficient dedicated supply ducts deliver fresh air to the living room and bedrooms while exhaust ducts pull stale air from bathrooms and the kitchen. Well in the comments dave roberts a senior engineer at the national renewable energy lab nrel wrote about a paper he co authored last year and included a link to it. This building america innovations profile describes building america research showing an unvented attic insulated along the roof line provides better energy performance than a vented attic when hvac ducts are located in the attic and there are numerous pe netrations through the ceiling deck.

Unventilated attics can help to mitigate energy loss through leaky ducts or ceiling fittings. Systems where condensing surface temperatures are not controlled and systems where condensing surface temperatures are controlled. Once all the system variables have been decided your hvac design professional can determine the most efficient ductwork design layout and calculate the correct duct size. Ensure proper ductwork sealing.

Sealing ducts placing ducts in unvented attics or crawl spaces and placing the ducts in conditioned space. To account for all the necessary factors many professionals use a tool called acca manual d. The duct insulation should include a vapor barrier cover. Ted also has inherited a powered attic ventilator.

Install insulation along the underside of the roof deck of an unvented attic rather than on the ceiling deck of a vented attic for either of two reasons. Remember that article i wrote about ducts installed against the roof deck and how i said it was probably the absolute worst single location for installing ducts. Choose the right duct size and layout. The energy savings touted by unvented attics can be as high as 20.

The design and construction guidelines in this report are the results of working with four builders and one energy consultant who routinely build homes with ducts. Ventilation ducts are separate from the heating and cooling. Use metal flex or fiber board ducts that are insulated to code. However if moisture is able to enter the unvented attic space it may lead to roofing panel issues.