Question

9.3 Consider a single-family detached residence. It is a single-story building with an attached heated garage. (Assume that the garage is insulated the same and maintained at the same level of comfort as the house living space.) The house has the fol- lowing characteristics. General 2972 ft 2516 ft? 360 ft 8 ft 2880 ft 332 ft 70 ft 120 ft 3420 ft Wall construction Roof construction Gross floor area (including garage) Living gross floor area Perimeter (including garage) Wall height Gross wall area Window area (openings) Door area (openings) Garage door area Roof area (including garage) Wood siding, bevel, 0.5 in. x 8 in. lapped Plywood sheathing 0.5 in. Framing, nominal 2 x 4, 16 in. center, with fiberglass batt insulation Gypsum, 0.5 in. Wood shingles, cedar shake Felt building paper Plywood sheathing 0.5 in. Framing, nominal 2 x 6 trusses, 24 in. centers 23° roof pitch Cellulose insulation, blown in, 8 in. Framing, nominal 2 x 6 trusses, 24 in. centers Gypsum, 0.5 in. Insulating glass, double, 0.5 in. airspace, wood sash and frame Loosely drawn interior drapery Solid-core wood doors, 1.75 in., no glazing no storm doors U=0.55 Btu/(h-ft. F) Ceiling construction Window construction Door construction Garage door construction (a) Calculate overall UA values for each element of the building envelope, i.e., wall, roof, win- dow, door.

Answer 1

Wall construction U 1/(R1+R2+R3+...) 0.577901063 Btu/(h ft^2 F)) Area Thermal resistance hft^2F/Btu 0.5/(12*0.0721)= 0.5/(12*0.0751) Materials Thermal conductivity in Btu/fth F UA Wood siding(0.5in) ft 2 0.0721 Plywood (0.5in) Fiberglass insulation (4in) Gypsum (0.5in) 0.554815801 0.0751 4/(12*0.0231) 0.5/(12*0.0982) Total= 2880 0.0231 14.43001443 0.062550684 180.1459696 0.0982 0.424304141 15.98703544 Roof construction Cedar wood 0.0982 10.18329939 Felt paper building Plywood (0.5in) 63.30032517 0.0231 43.29004329 0.018508867 3420 0.5/(12*0.0751) Total= 0.0751 0.554815801 54.02815848 Ceiling Construction 8/(12 0.133) = 0.5/(12*0.0982) = Cellulose(8in) 0.133 5.012531328 Gypsum(0.5in) 2516 0.0982 0.424304141 0.183930525 462.7691999 Total 5.43683547 Window construction O.5/(12*0.0175) = Total= Insulating glass (0.5 in) 2.380952381 0.42 139.44 0.0175 332 2.380952381 Door construction 1.75/(12*0.0578) = Total= Solid core wood door(1.75in) 0.0578 2.523068051 0.396342857 70 27.744 2.523068051 Garage door U 0.55Btu/(h ft^2 F) 0.55 120 66 Total UA 939.3994947 Btu/hF