Chapter 1.7, Problem 59P

Make a rough estimate of the total rate or conductive heat loss through the windows, walls, floor, and roof of typical house in a cold climate. Then estimate the cost of replacing this lost energy over the course of month. If possible, compare your estimate to a real utility bill. (Utility companies measure electricity by the Kilowatt-hour, a unit equal to 3.6 MJ. In the United States, natural gas is billed in therms, where $1therm={10}^{5}Btu$. Utility rates vary by region; I currently pay about 7 cents per kilowatt-hour for electricity and 50 cents per therm for natural gas.)