Expert: cleggsan - 8/16/2009

Question
If I have an air conditioner that is rated at 115 volts 620 watts and 5.6 amps, what is the effect of increasing the supplied voltage to 120 or 125 volts.  Does it produce a higher btu output, use less wattage or is there no real effect.
Thanks in advance.
bill cole

Answer
The greatest effect would be to overheat the compressor motor.  If it is rated for 115v then you ran it at 125v over a long period of time it will run hotter than normal.  Probably shorten the life of the AC by some small amount.

As to output it may increase its output a very small amount, but the AC unit is designed around the cooling properties and with the speed of the motor going maybe a little faster (depending on the coil  windings in the motor - it may not run any faster or it may actually run slower) and if, then, the cooling is a little greater it will reach the thermostat temperature a little quicker and go into the shut off cycle waiting for the temperature to kick it on again.

Bottom line is there will be only small differences in output cooling, efficiency and other performance parameters.  The biggest difference will be the potential overheating effect.

C