The Basics

If you have lived in a desert climate in the past then this may not be very helpful. On the other hand if you have not then it might. I wish someone had told me the information below when I first arrived in Tucson.

  • Evaporative coolers do not work in high humidly. How high is too high is complicated and outside the scope of this site. Click here  about psychrometrics
  • Do not operate the AC unit and the Evaporative Cooler at the same time. (Air conditioners remove moisture from the air and evaporative coolers add moisture.) You will use a lot of electricity, get little relief and possibly break one or both units.
  • When using the evaporative cooler a window in the room you are in needs to be open for you get relief from the heat.  
  • Changing the direction of the ceiling fan depending on the season does make a difference. In the summer, use the ceiling fan in the counterclockwise direction. While standing directly under the ceiling fan you should feel a cool breeze. The airflow produced creates a wind-chill effect, making you "feel" cooler. In the winter, reverse the motor and operate the ceiling fan at low speed in the clockwise direction. This produces a gentle updraft, which forces warm air near the ceiling down into the occupied space.
  • Ceiling fans cool people, not rooms. If the room is unoccupied, turn off the ceiling fan to save energy.
  • Evaporative coolers use up water and you see this reflected in your water bill.

AC / Heater Thermostat

The A/C thermostat is programmable for maximum energy savings. Program four time periods (wake, leave, return, sleep) each day, with different settings for weekdays and weekends. 

The thermostat automatically selects heating or cooling depending on the indoor temperature.

Set to the time you awaken and the temperature you want during the morning, until you leave for the day. Set to the time you leave home and the temperature you want while you are away (usually an energy-saving level). Set to the time you return home and the temperature you want during the evening, until bedtime. Set to the time you go to bed and the temperature you want overnight (usually an energy-saving level).

Operating Manual Owner's Guide

Evaporative Cooler Thermostat


The evaporative cooler thermostat includes a pre-wet cycle that allows the circulating pump to activate up to 2 minutes before the blower fan.This assures that only pre-cooled air enters your home. A flashing motor speed indicator light lets you know that the pads are pre-wetting and that the fan motor will activate shortly.

Automatic Operation

Depress ON /0FF button to illuminate any indicator light. Depress AUTO/MAN button to illuminate the"Auto" indicator light. Rotate selection knob to desired room temperature.

Important Note: To breathe cleaner and fresher air the evaporative cooler is installed with a Clean Machine pump. By automatically flushing out water in the pan every six hours of operation, the CleanMachine also reduces mineral build-up, extends pad life and conserves water (up to 3000 gallons per month compared to bleed-off systems).

Manual for MasterStat (Evaporative Cooler Thermostat)