When it comes to homes, two of the main culprits for an inefficient and uncomfortable living space are ventilated attics and crawlspaces. The main issue with ventilating attics and crawlspaces is the free exchange of outside air with inside air, which allows the pleasant, clean, conditioned indoor air escapes from the living space. So, these spaces are filled with hot and frigid air during summer and winter months, respectively. Because most heating and cooling equipment and ductwork are located in attics or crawlspaces, the outdoor air can reduce the temperature of warm duct air (during the winter) or increase the temperature of cold duct air (during the summer), simply due to heat transfer. These effects not only cause the air conditioning system to work harder, but also can result in condensation forming within the ducts, potentially leading to mold and negatively impacting the health of occupants. Additionally, outside air brings moisture, pollen, airborne particulates, and pollution into the home, not to mention the introduction of insects, rodents, and other pests through the vent openings. Insulating and sealing attics and crawlspaces with spray polyurethane foam is the most effective way to prevent these unwanted problems.