Wiring up the thermostat is usually pretty straightforward if an old one is being replaced. If a thermostat is being put in where one had never been before, that could involve running new wiring. The placement of the thermostat is also important so that its sensors can get an accurate reading of the temperature. A thermostat that is blocked by a bookcase or other large furniture will not get a good reading and will not perform efficiently.
An air conditioning system's SEER is especially important if you live in a climate that changes temperature dramatically. The SEER is determined by the cooling output during the winter divided by its electric input during the winter. The higher the rating, the more efficient it will be. In January of 2006, the U.S. put standards in place for cooling units which are still in effect today. They must have a minimum SEER of 13. So, if you live in a home with a system installed before the new standards went into effect, consider having it replaced. SEER 13 units increase home efficiency by 30 percent.
Some systems include an "economizer mode", which is sometimes called a "free-cooling mode". When economizing, the control system will open (fully or partially) the outside air damper and close (fully or partially) the return air damper. This will cause fresh, outside air to be supplied to the system. When the outside air is cooler than the demanded cool air, this will allow the demand to be met without using the mechanical supply of cooling (typically chilled water or a direct expansion "DX" unit), thus saving energy. The control system can compare the temperature of the outside air vs. return air, or it can compare the enthalpy of the air, as is frequently done in climates where humidity is more of an issue. In both cases, the outside air must be less energetic than the return air for the system to enter the economizer mode.
Cost Factors: The size of the unit, its efficiency and it’s single-stage, two-stage or variable-capacity are the top cost factors. Features like communicating technology and improved dehumidification performance also affect the price. Learn more about communicating technology here including the pros and cons, before being agreeing to a communicating system.
Just had my HVAC System restored and working again on a Sunday and before the 104 weather tomorrow!!!! Called Big Mountain Heating and Air and spoke to very helpful woman named Martina. She connected me to a Technician named Josh. He was at my home within a few minutes and tackled my Honey Well system's issues. He is both skilled, personable and better yet, he got my system up and going and safe. He installed a surge suppressor on the system to prevent power surges that can kick off any system, when the electric company has to reduce power, etc.  I will be using Big Mountain in the future. Truly grateful for such good service and people. Thank you!  I recommend this firm to everyone!
If you hear clicking that is followed by a hum or buzz, you’re probably hearing the fan motor attempting to start without the boost it needs from the capacitor. You can almost always conclude that the capacitor has failed. Sometimes you can get the compressor fan spinning (clockwise) by pushing it with a thin stick or long screwdriver poked through the grille. But the chances are good that this might work for one cycle, but the capacitor will fail next time the AC goes on. It’s best to replace the capacitor.