For the conditions in the previous exercise, describe a good strategy for use of a vapor diffusion retarder.

Data from in previous exercise

A building has indoor air conditions of 70°F dry bulb temperature and 40% relative humidity. Determine the direction of water vapor flow under the following outdoor air conditions that represent a dry, heating climate:
a. 32°F dry bulb temperature and 40% relative humidity (winter conditions)
b. 90°F dry bulb temperature and 20% relative humidity (summer conditions)