What does a blower door measure?

A blower door is a diagnostic tool used to measure the airtightness of a building. It works by creating a slight pressure difference between the inside and the outside environments, effectively drawing air out of the building. This process allows for the detection of air leaks, which are quantified in terms of the amount of air that flows through certain openings or gaps in the building's envelope.

The measurement of air leaks is crucial because it helps identify areas where conditioned air is escaping or unconditioned air is entering, which can significantly impact energy efficiency and comfort in a home. Understanding the square inches of holes or cracks helps a building analyst determine where improvements can be made to enhance insulation and reduce energy costs. By pinpointing these leaks, appropriate measures can be taken to seal and insulate the areas effectively, leading to a more energy-efficient and comfortable living environment.