HVAC System: Auto vs OnWe all have these two settings on our thermostats, but what is the difference between these 2 settings? Is it more advantageous to use one of these settings over the other? Which one is the best to use to extend the life of my HVAC system?

These fan settings control the AC blower within the HVAC system that circulates the cool air throughout your home. When set on AUTO, the fan goes on automatically until your desired temperature setting is reached at which time it will go off. When the home gets a little warmer or cooler (if you’re heating your home), the system will go back on again. When set to the ON position, the system runs continuously. It is least advantageous to set the thermostat to the ON setting because it is not energy efficient and will cost more money overall.

By having your HVAC system run continuously, you use far more energy than if your system was only running when heating or cooling and goes off. Your energy bill will be significantly higher. Also, by having the blower running continuously, there is greater wear and tear on the blower which can lead to high repair costs. This is an expensive component to have to replace. As the fan runs on and on, “relative humidity” will spike in the home to around 70% as opposed to an approximate average of 58% when the fan is set to AUTO. A “relative humidity” of 70% is the threshold where mold flourishes and spreads. With normal “duct leakage” of approximately 10% going into the home and an average of approximately 12% on the return air, “duct leakage” will significantly increase with the system continuously running causing your HVAC to be less effective in cooling or heating your home. This too will cause a significant increase in your energy bill.

AC Ambulance has been serving the Metro New Orleans area, in both residential and commercial properties, for four decades. We have built our reputation on trust and customer service, striving for complete customer satisfaction with our AC installation and repair services. We pride ourselves on having wonderful reviews on Angie’s List and long-standing customers. To learn how AC Ambulance can help you with service repairs or to have a new unit installed, contact us at (504) 467-1400 or by email at acambulance1@gmail.com.