Air leakage through the building envelope may or
may not be a significant source of energy waste. This
depends largely on ventilation requirements. For example,
it makes no sense to reduce the air leakage of a garage
door if the garage has a fixed ventilation requirement that
is higher than the leakage rate of the door. On the other
hand, you should minimize leakage around a similar door
that is installed in a heated warehouse where ventilation
requirements are minimal.