The standard amount of control voltage used by most central air conditioner units is 24 volts alternating current. This power is run through to the furnace control board when the thermostat is set to “Cool” or “Auto” and the temperature positioned below the current interior air temperature. The control board sends voltage to the condensing unit, closing the contacts on the contactor and starting the compressor and air conditioner fan.
The precise amount of voltage needed to run an air conditioning system depends on a few factors, including the size of the air conditioning unit and the overall Seasonal Energy Efficiency Ratio rating. Air conditioners with a high SEER rating have a higher ratio of cooling output when divided by the power input. In other words, units with a high SEER rating use less electricity to run. Consult the air conditioner manufacturer or installer regarding specific energy needs for your air conditioner.
Many energy efficient air conditioners have an inverter drive compressor, which means that the air conditioner compressor motor runs on direct current instead of alternating current. The air conditioner is plugged into a normal AC outlet and the power is converted into DC power in the air conditioner via an inverter. DC power allows for more precise cooling and might reduce overall energy costs.
The energy use of an air conditioner might be better controlled by the use of an air conditioner voltage regulator, which connects to the air conditioner and maintains the voltage level. This lowers normal voltage fluctuations and can reduce energy costs. Contact your air conditioner manufacturer or an electrician for recommendations.