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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.
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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
Four Wall types were analyzed: • 2x4 Stud wall with Stucco finish • Brick veneer wall • CMU • 2x6 Stud wall with Stucco finish
1st Wall: 2x4 Studs Composed of: • Stucco finish • Plywood sheathing • 2x4 Douglas fir studs • Insulation (R-13) • Gypsum board
2nd Wall: Brick Veneer Composed of: • Brick covering • Plywood sheathing • 2x4 Studs • Insulation • Gypsum board
3rd Wall: CMU Composed of: • Filled Cinder block • 2x4 Studs • Insulation • Gypsum board
4th Wall: 2x6 Stud Composed of: • Stucco Finish • Plywood sheathing • 2x6 Studs • Insulation (R-19) • Gypsum board
Heat Transfer of each Wall Batt Insulation Brick Expanded Polystyrene Cork Mastic
Conclusions: • 2x4 Brick Wall and 2x6 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.