A building's Enclosure System provides protection from weather and controls the flow of air, moisture, and heating/cooling between the interior and exterior. While it is generally known when water is flowing into a building, more attention to detail is required to stop the flow of air, retard the diffusion of moisture and minimize the transfer of heat. 

Effective enclosure details are provided in the construction documents, and personnel must be trained and/or receive on-site instruction about specifications and methods to properly assemble the enclosure.  Afterwards the building is tested to identify any leaks that are bound to occur. 

Low Energy Design can assist the project team in acheiving high quality outcomes. Inadequate attention to the building enclosure during construction results in poor performance, occupant discomfort, and premature failures. 

Buildings that have been given this attention or have deteriorated need to be evaluated, retrofitted to a desired level of thermal performance, and also tested. Testing is  done by inducing a pressure differential between the inside and outside using a blower fan that simulates the effects of wind, buoyant air, and mechanically induced pressures on the building enclosure.