"The Stack Effect"

" When we heat the air in our homes it becomes lighter than colder air. The buoyant air rises to the top of our house and leaks out of many dozen places, some large and some small. Since your attic is vented, think of the attic as outside. Think of a cubic foot of air as about the size of a basketball if it were square. For every basketball of air the leaks out of the house at the top, another basketball of air has to leak in at the bottom.

The air that leaks out takes our heat, comfort and money with it. The air that leaks in is cold in the winter, hot and humid in the summer and has dust in it making us uncomfortable. We have to add heat (money) to this new air, so we can be comfortable.

But once we heat the new air, it rises and leaks out of the top of the house again, and new outside air leaks in at the bottom to replace it again. The cycle never stops.

The only reason outside air leaks in is because inside air leaked out. If no air leaked out there wouldn't be any room for any new air to leak in. In this way we know that by sealing air leaks in the top of the house, we can make rooms at the bottom of the house less drafty without actually touching the bottom half of the house. "

- Home Comfort Science book

to learn more about the stack effect and home comfort in general, read our Home Comfort Science book included in the packet you receive prior to our home comfort evaluation.