CRES case studies
CRES · Put your knowledge to work in context.
The CRES (Certified Residential Energy Specialist) credential is aimed at people who assess and improve the energy performance of existing homes: home energy auditors, weatherization and retrofit technicians, insulation and air-sealing contractors, HVAC service staff moving into whole-house work, and raters or consultants supporting residential efficiency programs. It signals that a holder can look at a house as an interacting system rather than a list of unrelated upgrades. The CRES case studies are 5 cases and about 4,410 words.
1Ice Dams on a Cape Cod: Where the Thermal Boundary Actually Is
A 1,900 ft² 1½-story Cape Cod built in 1962 has 400 ft² of kneewall attic behind two second-floor bedrooms. The attic floor holds R-19 fiberglass batts, compressed to about 2 in.
896 words, about 4 min2A Return Duct in a Vented Crawlspace
A 1,400 ft² single-story ranch built in 1993 has all of its ductwork and the air handler in a vented crawlspace with a 6-mil vapor barrier covering about 60% of the soil. The system is a 2.5-ton split.
915 words, about 5 min3A 26°F Temperature Split and a Service Tech's Overcharge Diagnosis
A technician on a 3-ton R-410A split system measures 118 psig suction (about 40°F saturation) and recommends adding refrigerant because 'suction should be closer to 130.' The system has a TXV and a manufacturer target subcooling of 10°F; you measure 360 psig liquid pressure and 118°F liquid line temperature, which is 8°F subcooling. Outdoor ambient is 95°F.
853 words, about 4 min4Spillage in a Utility Closet with a 400 CFM Range Hood
A 1,600 ft² 1968 split-level has a natural-draft 40-gallon gas water heater and an 80% induced-draft furnace in a 6x8 ft utility closet with a louvered door and no dedicated combustion air duct. Both appliances vent into a single unlined 8x12 masonry chimney on an exterior wall; the water heater connector enters below the furnace connector.
849 words, about 4 min5The $12,000 Windows and the $4,500 Attic
The homeowner of a 2,200 ft² 1989 colonial has a 12,000 quote to replace all 14 double-pane vinyl windows, installed in 2004, and wants you to confirm that windows are why the living room is drafty and the second floor is cold. Your blower door reads 2,900 CFM50 (about 9.9 ACH50).
897 words, about 4 min