Consider a house in Blacksburg, Virginia. The typical annual space-heating load for this size of a house is 100 × 106 Bt

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Consider A House In Blacksburg Virginia The Typical Annual Space Heating Load For This Size Of A House Is 100 106 Bt 1 (162.99 KiB) Viewed 41 times

Consider a house in Blacksburg, Virginia. The typical annual space-heating load for this size of a house is 100 × 106 Btu. That is, with no insulation in the attic, we lose about 100 × 106 Btu per year. With insulation in the attic the amount of heat lost each year will be reduced. The value of energy savings that results from adding insulation and reducing heat loss is dependent on what type of residential heating furnace is installed. Assume that an electrical resistance furnace is installed by the builder, and its efficiency is near 100%. The cost of electricity is $0.14 per kWh. The cost of several insulation alternatives and associated space-heating loads for this house are given in the following table. Which amount of attic insulation is most economical? The life of the insulation is estimated to be 26 years. Amount of Insulation R19 R38 Investment cost ($) R11 2,500 74 x 106 6,500 66.4 x 106 Annual heating load (Btu/year) Recall that 1 Btu = 0.293 Wh and calculate the cost of electricity per million Btu. Fill in the table below. (Round to the nearest cent.) Investment cost ($) Cost of heat loss per year ($) Cost of heat loss over 26 years ($) Total life cycle costs ($) R11 2500 1066.52 27729.52 30229.52 3,500 69.8 x 106 R19 3500 1238.8 32208.8 35708.8 R30 5,300 67.2 x 106 R30 5300 1345.4 34980.4 40280.4 R38 6500 1386.4 36046.4 42546.4