It is found by determining from weather records for each day the difference between 65 degrees F and the mean temperature for that day. The sum of these differences for all the days in the heating season is the Degree Days for that locality. A measure of the mass per unit volume defined as the number of pounds per cubic foot of volume. Test procedure used to accurately determined thermal conductance or heat flow through a non-homogeneous building section. The construction of the Guarded Hot Box and the procedure for test is governed by ASTM Test Method C236.
Greater percentages indicate more light being reflected from the surface in question.
A unit expressing heat passage through a complete building section, including air films. Technically, it is heat transmission in BTU per hour, per square foot, per degree Fahrenheit of temperature difference from air to air for a composite building section. The lower the U-value, the better the insulating value of the building section. The lower the perm, the better the resistance to water vapor transmission. A measure of the ability of surface to absorb a fraction of the randomly incident sound.