Question: The owner of an older house in Wichita, Kansas, is considering replacing the existing double-door type wood framed single-pane windows with vinyl-framed double-pane windows with an air space of 6.4 mm. The new windows are of double-door type with metal spacers. The house is maintained at 22°C at all times, but heating is needed only when the outdoor temperature drops below 18°C because of the internal heat gain from people, lights, appliances, and the sun. The average winter temperature of Wichita is 7.1°C, and the house is heated by electric resistance heaters. If the unit cost of electricity is $0.085/kWh and the total window area of the house is 17 m2 , determine how much money the new windows will save the home owner per month in winter.
