For Home: A. A programmable thermostat costs about $200 and can be installed by a reasonably handy homeowner. If the amount of energy needed to maintain a given temperature is proportional to the difference between inside and outside temperatures, it will cost more to keep a house warmer in the winter (and cooler in the summer). Assume that the heating season in Lincoln is 180 days and that the amount of natural gas used in a typical heating season is 1000 therms. Assume that the average indoor temperature is 68F for the heating degree day calculation (normally 65F). Determine the cost of using a higher average indoor temperature (72F), and then using a night setback temperature of 58F for eight hours per night and 68F in the daytime. What is the payback period