Walls and Roof

Air movement into and out of the house was reduced with an inch of 2-pound closed-cell spray foam from the peaks of the cathedral ceilings to the cap on the Reddi-Wall insulated concrete forms. The cap and Reddi-wall were caulked and sealed to the slab. A vapor-air barrier of a waterproof membrane was put under the slab. The goal was to reduce significantly the movement of air, and therefore heat and water, through and between the roof, walls, and floor.

Subslab assembly

4 inch concrete slab, over 4 inches rigid insulation, over vapor-air barrier, over ~8 inches of stone, over clay subsoil.

Subslab R-value 20.0
Slab edge assembly

Slab edge (vertical description: 4 inch concrete slab, 4 inches rigid insulation, vapor-air barrier) down to clay subsoil abut directly on the polystyrene of the Reddi-Wall thereby closing vapor-air barrier around the house. One can start anywhere on the envelope and trace any cross section without encountering a break in the vapor-air barrier.

Slab edge R-value 20.0
Foundation wall assembly

Horizontal section going from outside to inside. Below ground: waterproof membrane on wall to concrete footer, 10 inch-wide Reddi-Wall insulated concrete form, 2.5 inches damp-spray cellulose, 0.5 inch gypsum board. Above ground: stucco finish over welded wire mesh, Tyvek rainwrap, 10 inch-wide Reddi-Wall insulated concrete form, 2.5 inches damp-spray cellulose, 0.5 inch gypsum board.

Foundation wall R-value 35.5
Above grade wall assembly

Horizontal section going from outside to inside: fiber-cement siding and trim with Tyvek rainwrap on 1/2 inch OSB sheathing, 1 inch of 2-pound closed-cell spray foam vapor-air barrier, double 2 x 4 wall with precut staggered (as possible) studs, 11 inches of damp-spray cellulose insulation, 1/2 inch gypsum board.

Above grade wall R-value 47.5
Flat attic assembly


Cathedral ceiling assembly

Cross section from outside to inside: 24-gauge raised-seam metal roof, 30# roof felt, 5/8 inch OSB sheathing, 16 inch engineered rafters with 1 inch of 2-pound closed-cell foam vapor-air barrier and 15 inches of dense packed cellulose, 5/8 inch gypsum board.

Cathedral ceiling R-value 62.5
Roof Assembly

All roofs are hot above cathedral ceiling.

Roof R-value 62.5

Windows and Doors

Window Assembly:

Lowen high performance windows. Triple pane, low-E argon with warm edge spacers on E, N, and W facades and Double pane low-E argon with warm edge spacers on S facade and tuned for solar gain and composite hard coat LO E.

Windows were custom made and each window had its own U factor, Solar Heat Gain Coefficient, and Visible Light Transmittance. Typical for N, E, and W. windows are U 0.22, SHGC 0.24, and VT 042. Typical for S windows are U 0.29, SHGC 0.39, and VT 048. Given below are averages of the typical values just given for N, E, and W windows and S windows.

Door Assembly:

Fiber glass with an R value of 8. When the outside temperature is around 10 degrees F, the inside of the door does not feel cool to the hand. We have 4 doors.

Average window U-factor 0.25
Solar Heat Gain Coefficient 0.32
Visible Light Transmittance 0.45
Door U-Factor 0.13
Door Area 76 sq ft

Mechanical Systems

Space cooling - Manufacturer & Model Carrier heat pump, model 50YCV024RLB301
Space heating - Manufacturer & Model HearthStone Tribute (soap stone, 36,000 BTU, 1,300 sq. ft.) , Carrier heat pump, model 50YCV024RLB301, Climate Master AG, electric heater (never used, resistent heat to expensive)
Space heating - capacity 11 kW
Domestic hot water - Manufacturer & Model Steible, on-demand electric,Tempra 20 B, provides max flow of 2.3 gallons of 115 F hot water that is 60 degrees hotter than incoming water.
Ventilation - Manufacturer & Model Carrier, Model: 50YCV024RLB301, Serial #: 3308V59012, Climate Master AG, electric heater
Lighting Manufacturer and Model
Lighting Efficiency Almost all lighting fixtures have LED bulbs with others being CF bulbs.
Mechanical Equipment Installation Details and Comments

Blower door


Air Changes per hour, ACH50 1.10 ACH50
Air Changes per hour, CFM50