 We have warm air on the inside of the house. We may not have a lot of humidity, but we've got more humidity than is outside. So let's say in the summer, in the wintertime, we have 50% humidity, 60% humidity, 30% humidity. But outside in the wintertime, a lot of times we'll have 10%, 15%, 20% humidity. It's cold, and we have glass. And if we have non-insulated glass or we don't have a thermal break in there,