ENERGY SAVINGS OF STANDARD WALL TYPES IN NATURAL

Assumptions: Outside wall is exposed to convection due to wind. Convection is approximated by

Measurements: Outside temperature of 20 degrees F Inside temperature of 70 degrees F Outside

Four Wall types were analyzed: 2 x 4 Stud wall with Stucco finish Brick

1 st Wall: 2 x 4 Studs Composed of: Stucco finish Plywood sheathing 2

2 nd Wall: Brick Veneer Composed of: Brick covering Plywood sheathing 2 x 4

3 rd Wall: CMU Composed of: Filled Cinder block 2 x 4 Studs Insulation

4 th Wall: 2 x 6 Stud Composed of: Stucco Finish Plywood sheathing 2

Heat Transfer of each Wall Performance 1200 Heat Loss (Watts) 1000 800 600 Stucco

Monthly Cost of each Wall Savings over 2 x 4 Stucco Dollars per Month

Conclusions: 2 x 4 Brick Wall and 2 x 6 stucco wall types are

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ENERGY SAVINGS OF STANDARD WALL TYPES IN NATURAL GAS HEATED HOMES Trevor Hedman Kendall Hill

Assumptions: Outside wall is exposed to convection due to wind. Convection is approximated by flow over a flat plate. Inside Wall temperature is constant at room temperature. Radiation is neglected.

Measurements: Outside temperature of 20 degrees F Inside temperature of 70 degrees F Outside wind speed of 8. 8 mph used (monthly average) The section parallel to the wind was measured to be 22’ long and 8’ high

Convection Coefficient Calculations

Thermal Circuit Analysis

Four Wall types were analyzed: 2 x 4 Stud wall with Stucco finish Brick veneer wall CMU 2 x 6 Stud wall with Stucco finish

1 st Wall: 2 x 4 Studs Composed of: Stucco finish Plywood sheathing 2 x 4 Douglas fir studs Insulation (R-13) Gypsum board

2 nd Wall: Brick Veneer Composed of: Brick covering Plywood sheathing 2 x 4 Studs Insulation Gypsum board

3 rd Wall: CMU Composed of: Filled Cinder block 2 x 4 Studs Insulation Gypsum board

4 th Wall: 2 x 6 Stud Composed of: Stucco Finish Plywood sheathing 2 x 6 Studs Insulation (R-19) Gypsum board

Heat Transfer of each Wall Performance 1200 Heat Loss (Watts) 1000 800 600 Stucco Finish Brick Veneer CMU Block w/ Furring 400 Stucco (2 x 6) 200 0 0. 2 0. 4 0. 6 0. 8 Thermal Conductivity (W/m-K) Batt Insulation Expanded Polystyrene Cork Mastic 1 1. 2 Brick 1. 4

Monthly Cost of each Wall Savings over 2 x 4 Stucco Dollars per Month below 2 x 4 Stucco costs 10 Brick Savings 9 8 CMU Savings 7 2 x 6 Stucco Savings 6 5 4 3 2 1 0 0. 1 0. 2 0. 3 0. 4 0. 5 0. 6 0. 7 0. 8 0. 9 Thermal Conductivity (W/m-K) 1. 0 1. 1 1. 2 1. 3 1. 4

Conclusions: 2 x 4 Brick Wall and 2 x 6 stucco wall types are very similar when insulation of k=0. 5 (typical batt insulation) is used CMU wall has the highest thermal resistance for most k values and the best monthly savings. It costs more to begin with but will save you money in the long run. At k values greater than 0. 7 changing insulation type does significantly reduce heat transfer in walls. Don’t spend extra money to upgrade insulation unless the k value is less than 0. 7.