There are endless reasons why your utility bills might be high, but here are some reasons why your heating and cooling is costing you a fortune.
1. Your home is not adequately insulated. You may have inferior windows, minimal wall and roof insulation, etc. All these things prevent your home from blocking out the heat and cold from outside. A house that is not well insulated will always be more difficult to heat in the winter and cool in the summer.
2. Your system is not maintained correctly. Poorly maintained units do not run efficiently and will cost you more to operate.
3. Your filter is dirty and is not changed often enough. A dirty filter restricts airflow and causes your unit to run harder and therefore use more energy.
4. Your system is old and inefficient. New systems are more efficient and use less energy to operate than old systems.
5. You have an oversized unit. Having a unit that is too big for your home will cause short cycling of the unit. The unit will come on and cool the house rapidly while drawing a lot of power. It will then shut off for a short while, turn on for a short while, shut off for a short while and so on. This quick cycling process draws more energy than would be used under the regular operation of an appropriately sized unit. The system on start-up takes about 5 minutes of operation to achieve full capacity and efficiency. Short cycling also does not allow the system to dehumidify properly.
6. You have undersized ductwork. Undersized ductwork chokes the system and causes the unit to work harder to move air. Try blowing through a large diameter straw; now try to blow through a small diameter straw. It takes much more effort to blow through the small diameter straw than the large one. This extra work again results in more energy consumption.
7. You adjust your thermostat too often throughout the day. Yo-yoing with your thermostat (bumping it up a few degrees, then down, then up), while you are home, causes a significant loss in energy efficiency. Your air conditioning unit functions best when it is left in one setting. This allows it to cycle properly and run at maximum efficiency.
8. You turn your unit off while you are away at work or adjust the set point too much.