The reason to consider these factors is time for "payback". If the additional cost for a super high-efficiency system, as opposed to a standard system is $900 and you use the system for three months out of the year, it may take as long as 10 years to recoup the initial cost of the upgrade. This means that if you save $100 per season, you're looking at nine years for payback. High efficiency systems are a great thing, but not in every case or every home. If you have a small 1,200 sq. ft. home, we would not suggest such a system for you. Your payback time may exceed the lifespan on the system itself. In short, consider all these factors when you're ready to purchase a new comfort system.
The thermostat is the main controller of your home heating system. Using a setback thermostat that sets the heating system back when the house in not occupied is a great way to reduce heating costs. Lower the temperature by no more than eight?. Any more than that is counterproductive and causes the heating system to run too long to reach comfort levels. Never use a setback in the summer, because doing this will cause higher utility bills. Consider the temperature swings in winter: 70° indoor, 30° outdoor for a 40° temperature difference. For the summer, adjust your setback to 70° indoor when the temperature is 95° outside for a 25° difference.