This is a quick video we took yesterday when we were doing an energy assessment of a commercial building… Check out the air leakage coming from the windows! We used a blower door test to depressurize the room and a smoke pencil to enable a visual inspection. This testing method really helped to identify critical areas to air seal in this commercial building. Just a simple measure of caulking around these windows will help to drastically reduce air movement which will reduce utility bills (heating and cooling!) and increase comfort for the people sitting near them.