MAR 28, 2017

Summer in Phoenix means some excruciatingly hot days … I guess it is our way of paying penance for the all of the beautiful weather we enjoy the rest of the year. And so, many Phoenix homeowner are gearing up their air conditioning systems and making all necessary preparations to make sure that their air conditioners will keep their homes comfortable and their utility bills reasonable. Your air conditioning is, after all, likely to be the single thing that uses the most energy in your home during the summer months.

But once you have taken all of the necessary steps to ensure that your AC unit is in good working order, do you know how to operate the machine so that all of your hard work is not in vain? Knowing how to set your AC thermostat is a good place to start.


While some older homes still have electromechanical thermostats, the vast majority of them are now electric. And with new AC thermostat technology advancing significantly over the past few years, AC thermostat settings and how they impact energy savings is top of mind for many homeowners.

Whether electromechanical or a newer electric model, an AC thermostat works by opening or closing an electrical circuit that powers and air conditioning unit, based on the temperature in the house.


Obviously, the less your air conditioning unit needs to cool the house, the less energy it will use. Setting the temperature a few degrees higher can result in significant energy savings. But aside from picking which temperature you would like to keep your house at (the threshold for which the unit will turn on or off), you also have a setting for the air conditioner’s fan–these settings will be “On” or “Auto.” This is where many Phoenix homeowner get confused about which one they should use.

If you simply use the “On” setting, the air conditioner’s fan will blow constantly, regardless of what the AC thermostat says. This leads to not only decreased energy savings because of the extra electricity being used to power the fan–it could easily be hundred of extra hours per month–but it also hurts your pocketbook because the increased wear and tear on the parts means that you will be more likely to have to get a professional air conditioner repair or replace parts sooner rather than later. Alternatively, if you stick with the “Auto” setting, the fan will not turn on unless your AC thermostat temperature has been met and the air conditioner is actively pumping cool air into your home.

Some people also think that having the fan in the “On” position is helpful in making the air in their home less humid, but that is definitely not the case. In fact, having your AC thermostat fan set to “On” can make the humidity in your home worse because it increases the amount of condensation that will be pushed back into your house. And normal ductwork leaks mean that while condensation is being pushed into your house, there will probably be some cool air leaving too.

The only real downside to having your AC thermostat set to “Auto” is that the temperature in your home may be less even than if it is set to “On.” Newer AC thermostats have a third option, “Circulate,” which is a sort of a combination of the two classic settings. Under this AC thermostat setting, the fan runs for a certain amount of time every hour. This allows the fan to evenly distribute air throughout the house without all of the negatives of having the AC thermostat set to “On” and the fan running constantly.


If your air conditioner is in good working order, then your focus should be on increasing efficiency and energy savings while maintaining a cool home during the hot summer. Knowing and informing the rest of your family on the proper setting for your AC thermostat is key to maximizing your money, energy savings and summer comfort.

If you needs some help troubleshooting an air conditioner or AC thermostat that does not seem to be working properly, check out our blog post on the topic or contact us for some advice. If you have taken all of these steps and still do not think that your air conditioner is keeping your home cool in an efficient manner, give us a call in that case too. It may be that the AC unit is improperly sized for the home or another issue with airflow. With years of experience, we are well-equipped to diagnose air conditioning problems for all packages (rooftop) and split systems (the furnace and the condenser unit are separate) alike.