All human activity requires the use of oxygen, and results in the buildup of the carbon dioxide that is exhaled. The greater the level of activity, the more oxygen is used and the more carbon dioxide that must be removed from the space. Proper ventilation must provide adequate fresh air and also prevent the accumulation of carbon dioxide.
Insufficient ventilation can exacerbate comfort within the building.
Maintenance tasks Many simple jobs that are a normal part of building maintenance are often not done promptly. One such item is replacing cracked or broken windows. This is not only a safety precaution but also minimizes the infiltration of outside air into a space. A second project is to adjust exterior door closers to close the door swiftly and completely. A small permanent crack around a large door can lose enough energy in a year to pay for complete weather-stripping.