Title-24 Question of The Week

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Question: What is a high performance attic?

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Answer: The new 2016 Title-24 Building Efficiency Standards now has prescriptive requirements for high performance attics using a number of construction methods.  The underlying principle for all methods involves reducing attic temperatures with the additional benefit of improving the performance of HVAC ducts that travel thru the attic.  This goal can be accomplished by using a standard ventilated attic configuration with energy saving improvements, or by constructing an unventilated attic that behaves thermally like a conditioned space.

Ventilated Attic:

Ventilated attic option provides for two basic paths toward compliance.  The first path is called Ducts In Conditioned Space or DCS.  The DCS option is achieved when the ducts and the air handlers are within the thermal envelope and air barrier of the building.  This option involves constructing a standard vented attic with an additional layer of insulation directly underneath or above the roof deck as follows:

ou will need to use the larger of either the rated wattage of the recessed can fixture that is listed on the UL label or the wattage indicated in Table 6-3 found on page 6-15 of the 2008 Residential Compliance Manual.  The wattage assumptions in Table 6-3 vary depending on the size of the recessed fixture (diameter of the aperture) and the ceiling height.   click on table below to enlarge

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