Susan Brown of Brownstone’s Energy Services arrived to do a Thermal Bypass Checklist and the Blower test for the air conditioning system. Her equipment consists of deep knowledge of the thermal properties of different materials, a practiced eye in spotting gaps in the building envelope, and a blower device and flexible hoses that send a fog like substance through the a/c system.
Since this was being done before the drywall has been installed, Susan was able to move systematically room by room examining the insulation and other materials. Icenyne foam has been sprayed in the attic and on the walls of the building. This gives a high R value and places all the a/c ductwork in air conditioned space. In thermal barrier terms, i.e. keeping the hot, humid air out of the building, this is great. I did not realize that wood was not as good a thermal barrier. Since wood had been used under the windows to insure a snug fit, some additional insulation has to be installed (the building has 2 x 6 studs, so Susan suggested that next time, we use 2 x 4s to fill the gap under the window and apply 2 inches of insulation over that). Any small gaps spotted during the inspection were filled immediately with foam but the larger spaces require a mechanic to return to the sight.
Windows and doors at the Folly are by Kolbe – aluminum clad wood frames with insulated, low e glass. They allow a lot of natural light though but with very little heat gain. Since we are in coastal Florida it is also important that they be hurricane resistant and load tested to 140 mph winds.
Folly has three a/c systems since some sections of the house are likely to be used more than others. The most used areas have a larger separate system. Before Susan’s arrival, all the grills had been sealed and the ducts checked for leaks as best as possible. At the air intake for each system, Susan set up her blower. A 4-inch section of the grill farthest away from the air intake was uncovered. Then Susan started up her machine and we all held our breath. We scanned the line of the ductwork to spot smoke coming out. Nothing. After about 5 minutes smoke started pouring out of that distant grill followed by a general joyous shout. We have an airtight system! Each of the three systems was checked in this way with the same result. This is a credit to our a/c installer, Manuel from Barker Air Conditioning. Susan told us that this rarely happens as there are often places along the length of ducts that have small leaks. Everyone here feels good about a job well done! Susan did suggest that in places were unlike materials meet, e.g. where a flexible hose meets an aluminum housing, that Manuel seal the joints with mastic. This seal is less likely to fail in our hot, humid climate.
Although this was a “test”, everyone involved – architect, contractor, LEED consultant and homeowner – felt it was a productive and worthwhile session. Folly passed her tests with flying colors.
