Targeted air sealing to an already reasonably tight, well-insulated building originally built in 1994.
Slab edge assembly
Slab edge R-value
Foundation wall assembly
8" poured concrete wall with interior insulation.
Most locations: interior stud wall with 6" fiberglass (R-17)
Tight locations (e.g., stairwell): 2" XPS (R-10)
Note: Foundation R-value noted below is approximate weighted average.
Foundation wall R-value
Above grade wall assembly
7” dense-packed cellulose
2x6 stud wall with 2x3 strapping for thermal break
Above grade wall R-value
Flat attic assembly
N/A, this is a cape
Cathedral ceiling assembly
2x12 with 10" fiberglass (vented)
Cathedral ceiling R-value
See cape ceiling above
Windows and Doors
Existing Weathershield clad wood casements, double-glazed, low-e, Argon-filled.
Do not have information on SHGC and VLT
Existing insulated steel doors (Therma-Tru?)
One with full window, R-3.2
One with half window, R-5
Average window U-factor
40 sq ft
Space heating - Manufacturer & Model
Mitsubishi MSZ-FE12NA, Mitsubishi MSZ-FE09NA
Space heating - capacity
Domestic hot water - Manufacturer & Model
Super-Stor super-insulated electric water tank backing up SDHW
Domestic hot water - capacity
Ventilation - Manufacturer & Model
FanTech SH704 (HRV)
Lighting Manufacturer and Model
Mechanical Equipment Installation Details and Comments
Lesson learned: It appears the mechanical work, conducted after air sealing, may have introduced significant air leakage. We have yet to have energy auditors return to find out if this was the case, or whether there is another explanation for the following: An initial a 2-door blower door test (1 door on each unit of the duplex to equalize pressure) showed 503 ACH50 for the unit to be renovated. During air-sealing, a one-door blower door test showed a reduction from 850 to 739 ACH50 for the duplex. As only the one unit was air sealed, one would expect the 111 reduction would apply only to that unit, resulting in 392 ACH50. However, a 2-door test performed after mechanical work showed 640 CFM50. (No sleuthing for location of air leakage was done at the time, for reasons too complicated to explain.) That last number is listed below, even though there is still an element of doubt.