page_title: Blower door
section_title: Blower door metrics
hierarchical_section_title: Blower door / Blower door metrics
caption_attribution_description: Français&#160;: appareil pour test infiltrometrie English: Related to Blower Door testing of housing: [1]
context_page_description: A blower door is a machine used to measure the airtightness of buildings. It can also be used to measure airflow between building zones, to test ductwork airtightness and to help physically locate air leakage sites in the building envelope.
  There are three primary components to a blower door: a calibrated, variable-speed fan, capable of inducing a range of airflows sufficient to pressurize and depressurize a variety of building sizes, a pressure measurement instrument, called a manometer, to simultaneously measure the pressure differential induced across the face of the fan and across the building envelope, as a result of fan airflow, and a mounting system, used to mount the fan in a building opening, such as a door or a window.
  Air tightness testing is usually thought of in residential settings. It is becoming more common in commercial settings. The General Services Administration requires testing of new US federal government buildings.
  A variety of blower door airtightness metrics can be produced using the combination of building-to-outside pressure and fan airflow measurements. These metrics differ in their measurement methods, calculation and uses.
context_section_description: Depending on how a blower door test is performed, a wide variety of airtightness and building airflow metrics can be derived from the gathered data.  Some of the most common metrics and their variations are discussed below. The examples below use the SI pressure measurement unit Pascal (pa). Imperial measurement units are commonly water column inches (WC Inch or IWC). The conversion rate is 1 WC inch = 249 Pa. Examples below use the commonly accepted pressure of 50pa which is 20% of 1 IWC.
caption: Blower door installation (France)
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