Building Science Work
Air infiltration through large cracks in the building envelope allows more frequent changes of conditioned air in living areas. These frequent air changes cause the HVAC system to cycle more often to keep a consistent temperature and comfort level. The presence of humidity in the summer and the lack of humidity in the winter also causes the temperature to feel less comfortable. Summer months tend to work the air conditioner harder to remove humidity that causes the temperature to feel warmer. 
A blower door and duct blaster measure pressure and fan flow and calculates CFM, cubic feet per minute of air leaking and moving through the fan. These calculations can show pressure differences of building zones and help determine where to begin air sealing first. This valuable tool can pin point air leaks by telling us which zones are leaking the worst and therefore where to concentrate sealing efforts. It tells us how effective the sealing of the leaks was and if there is adequate minimum ventilaiton and if balanced ventilation is needed. For good Indoor Air Quality it is preferable not to have air leaks from the crawl space, basement, attic or other areas where air pollutants can infiltrate the conditioned air distribution system. Calibrated fans and digital manometer guages allow data to be recorded and analyzed accurately.
