Issue link: http://cp.revolio.com/i/1121626
Polystyrene Foam Insulation in Long-Term Building Applications – Effective R-values Page 7 Climate Condition "Inside" Temp. "Outside" Temp. Temp. Diff. Mean Temp. Very cold 72°F (22°C) 0°F (-18°C) 72°F (40°C) 36°F (2°C) Cold 72°F (22°C) 36°F (2°C) 36°F (20°C) 54°F (12°C) Hot 72°F (22°C) 108°F (42°C) 36°F (20°C) 90°F (32°C) Solar heated 72°F (22°C) 144°F (62°C) 72°F (40°C) 108°F (42°C) Table 2. Mean Temperatures as a Func on of Climate Condi on 15 It is immediately apparent that the various climate conditions across North America do not correlate well with a mean temperature of 75°F (24°C). A mean temperature of less than 40°F (4°C) would be appropriate for winter conditions in very cold climates, and a mean temperature of 90°F (32°C) or higher would be appropriate for summer conditions in a hot climate. With insulation generally installed between the exterior and interior of the building envelope, the mean temperature of the insulation depends largely upon the exterior temperature. As Figure 2 shows, insulation performance depends on the mean temperature, which is especially important for those products with a non-linear temperature dependence. The mean temperature applied should be based on climate conditions as well as the insulation location within the building envelope. Figure 3. Winter & Summer Climate Condi ons