What Are the Most Common Sources of Residential Air Leaks?

All buildings have air leak paths. In many homes, air leaking through holes and cracks is responsible for up to one-fifth of heating and cooling costs. The biggest sources of air leaks are usually located in common areas of the house such as around pipes, ducts, windows, and doors. However, we should also not overlook the hidden air leaks that can be found in attics, basements, as well as around wiring holes and chimneys. These troublesome areas are a big contributor to energy loss too.