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Understanding Thermal Comfort Factors

Clothing Level (CLO)

CLO is a numerical value describing thermal insulation provided by clothing, ranging from 0.5 to 1.5, and is referenced by ASHRAE 55.

There are two basic methods of determining an individual’s CLO value. The first is based upon entire outfit; the second is by summing the total CLO values for each article of clothing. The first method is likely to be a more time-effective approach to estimating a building occupant’s attire.