BPI Envelope case studies
BPI Envelope · Put your knowledge to work in context.
BPI publishes a family of home performance certifications and certificates, and its stated mission is "to advance the home performance industry by providing nationally recognized standards and credentials that ensure homes are comfortable, healthy, safe, durable, and energy efficient." The Envelope Professional credential is aimed at practitioners who assess and improve the building shell - insulation, air sealing, moisture control, windows and doors - and who need to demonstrate that knowledge to employers, programs, and homeowners. This study page is an independent preparation resource and is not affiliated with, endorsed by, or sponsored by the Building Performance Institute. The BPI Envelope case studies are 5 cases and about 2,154 words.
1The Cold Bonus Room Over the Garage
A two-story house has a bonus room built over an attached garage. The homeowner reports that the room is cold in winter (floor surface about 52°F while the rest of the second floor is 68°F) and that the room above the garage door is uncomfortably drafty.
464 words, about 2 min2Bath Fan That Won't Clear the Mirror
A homeowner in a tight, well-sealed 1,800 ft² house complains that the bathroom mirror fogs for 20 minutes after showers and that the bathroom smells musty. The existing exhaust fan is rated 80 CFM at 0.1 in.
431 words, about 2 min3Condensation on the Crawlspace Joists
A vented crawlspace under a 1,200 ft² single-story house has fiberglass batts between the floor joists with the kraft facing up against the subfloor. In summer, the homeowner notices condensation dripping from the joists and a musty odor.
412 words, about 2 min4Windows That Sweat and a Cold Second Floor
A 1970s house has double-pane windows with aluminum frames and no low-E coating. In winter, the homeowner reports heavy condensation on the inside of the glass and frames, especially in bedrooms, and that the second floor is 5°F colder than the first.
399 words, about 2 min5The Depressurized House and the Backdrafting Water Heater
A 1,500 ft² house has a naturally drafted gas water heater in a closet with a louvered door, a range hood rated 600 CFM, and two bath fans at 80 CFM each. During a blower door test with the house at 50 Pa, the technician runs the range hood and both bath fans.
448 words, about 2 min