There is more to attic insulation than just picking the cheapest material to achieve a given R-value. Almost every common attic insulation has some peculiarity that must be considered. Also we are still learning new things about insulation performance in different climates. This column is an update of important attic insulation issues that are commonly overlooked or misunderstood. Heat Doesn't Rise The most common misconception about attic insulation is that attics need higher R-value than walls because heat rises. This is not true. Heat does not rise; it travels equally in all directions — up, down, and sideways. Warm air does tend to rise. However in rooms with high solar gain, the air temperature near the ceiling of a well-insulated house is typically
