It's always changing: Some newer thermostats take advantage of wireless technology. You can adjust your thermostat remotely so that if you leave and forget to adjust it, or if you are going to be home later than you thought, you can adjust it via your smartphone. Some can even give you reports on how efficient your system is performing based on usage. These are very efficient models, but they are also very expensive with some costing over $250.00.
Deciding if central air is worth the cost depends on your needs and local housing market. If you live in a hotter climate, it can definitely be worth the price. Not only can it keep your home at a comfortable temperature, but air conditioning can even save lives during extreme heat waves. But in a milder zone without severe temperatures, window units, fans or the breeze from an open window could be adequate.
An AC contactor is a $25 mechanical relay that uses low-voltage power from the thermostat to switch 220-volt high-amperage current to the compressor and condenser fan. AC contactors can wear out and are at the top of the list of common air conditioning service failures. Even if your AC contactor is working, it pays to replace it every five years or so. Unscrew the old AC contactor before removing the wires. Then move the wires to the new unit (Photo 6).
We installed a TRANE XL18 HVAC with a TRANE HV80 furnace 16 years ago and it still works great in Tucson, AZ. We inquired into a replacement for the future since the R-22 refrigerant will be off market at the end of this year. Our maintenance folks want to sell me a new system anyway (even though the TRANE works great). We are considering the BOSCH Inverter heat pump as a lower cost option down the road. Watch out for the tricky salesmen trying to sell beer at champagne prices though. Get estimates on whether you need to replace your current system and how much it could cost. And if they are factory certified.
Clean the condenser fan blades before the start of the cooling season. Brush any dust or debris off gently and then uncover the condenser coils, gently cleaning the dirty side. Then wrap the motor and other electrical components in plastic bags and gently spray from the inside with a hose. Now check the base pan under the unit and clear it out of any debris that has gathered.
In addition to the information below, see these two articles for the general care and maintenance of your air conditioner: Preparing Your Air Conditioner for Summer and How to Replace Furnace & AC Filters. Most noteworthy, you should replace the filters at least twice a year, before the heating and cooling seasons. For information on furnace problems, please see Furnace Not Working.