Unfortunately, most residential buildings were constructed before the size of the problem, and the ease of the solution, were so widely known. For example, in cold weather, the heated air inside the house flows out. Frigid outside air and moisture leak in rooms feel drafty. This uncontrolled air disrupts the temperature, air pressure and humidity of the living space, in any weather. The heating and cooling system has to work harder to maintain your family's comfort.
Energy is wasted and that causes higher utility bills.
Air infiltration is caused by leaks around windows and doors, and by the spaces, joints, voids and cracks hidden inside the structure. Hidden is the problem. Once the house is finished, gaps become invisible but they are there. Air penetrates the building shell in one location, flows through interior cavities and emerges at a different location. Typically, this uncontrolled air travels through the house inside walls and ceilings, under baseboards, and along hidden pathways in the plumbing and electrical system.