Many people think that a house has to "breathe." This is simply not true.
However, if the thermal envelope of a home is not well sealed and doesn't have controlled ventilation, air moving through the structure day in and day out causes increased discomfort and high utility bills.
This air movement can be as much as 30% of the home's energy requirements.
Careful attention to caulking and sealing of all penetrations in the structure will make the home more comfortable and decrease the size of the heating and cooling equipment thereby, reducing the utility bills.