Summer is coming. Is your AC ready?

It doesn’t feel like mid-June here, but air conditioning season is coming (and Ned Stark won’t help you.) My friends at U.S. Inspect published a useful list of common problems in central AC systems (see below.)

atticfanSave on your energy bills (heating and cooling accounts for 56% of home energy usage.) The sun’s heat works against your desire to keep you house cool. Shade your living space, shade your air conditioner condenser (but leave circulation space), and insulate your attic, especially if your AC blower is up there. Use fans, both to move air in your rooms and to exhaust hot air from your attic, whether you have AC or not.

Central air conditioning systems are getting more common. I see more traditional central air conditioning (with one condenser and a furnace used to circulate the cold air) and an increasing number of ductless split HVAC (heating, ventilation, air conditioning) systems, which have individual blowers built into several room’s walls that are cooled by a single condenser.

Single room units work well for people who are comfortable with using fans, except on the hottest days and nights. Some of these are installed annually in windows; some are permanently installed in an outside wall. Measure the room in cubic feet before choosing a unit. Buy one that isn’t overpowered. It doesn’t make you cooler and it wastes energy. Window units are a lot of work to install and uninstall, but they do the job, room by room. Install them so that the condensing water drains out.

 Common AC Problems (reprinted from US Inspect):

  • AC condenserRefrigerant leaks.  If your AC is low on refrigerant, it was undercharged at installation or, more likely, it leaks.  If the system leaks, you can add refrigerant until the cows come home but that’s expensive, tedious and harmful to the environment.  Much wiser to secure a trained technician to fix any leaks, test the repairs, and then charge the system with the correct amount of refrigerant.  The performance and efficiency of your AC unit is optimal when the refrigerant charge exactly matches the manufacturer’s specification, and is neither undercharged nor overcharged.
  • Electric control failure.  The compressor and fan controls wear out, especially when the AC turns on and off frequently, which is common when a system is oversized.  Because corrosion of wire and terminals also is a problem in many systems, electrical connections and contacts should be checked during a professional service call.
  • Sensor problems.  Room AC units feature a thermostat sensor, located behind the control panel, which measures the temperature of air coming into the evaporative coil.  If the sensor is knocked out of position, the AC unit could cycle constantly or behave erratically.
  • Drainage problems.  When it’s humid outside, check the condensate drain to make sure it is draining properly.  Room AC units may not drain properly if not mounted level, which could cause leaks and water damage.