With increasing emphasis on energy conservation, the heat loss from buildings has become a major concern. For a small tract house the typical exterior surface areas and R-factors (area × thermal resistance) are listed below

(a) Calculate the rate of heat loss from the house when the interior temperature is 22?C and the exterior is ??5?C. (b) Suggest ways and means to reduce the heat loss and show quantitatively the effect of doubling the wall insulation and the substitution of double glazed windows (thermal resistance = 0.2 m2 K/W) for the single glazed type in the table above.GIVENSmall houseAreas and thermal resistances shown in the table aboveInterior temperature = 22?CExterior temperature = ??5?CASSUMPTIONSAll heat transfer can be treated as one dimensionalSteady state has been reachedThe temperatures given are wall surface temperaturesInfiltration is negligibleThe exterior temperature of the floor is the same as the rest of the house

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Area (m) R-Factors = Area x Thermal Resistance [(m? K/W)] Element Walls 150 2.0 2.8 2.0 Ceiling Floor 120 120 20 Windows Doors 0.1 0.5