The thermostat setting for your air conditioner gives you a choice: Auto or on. Don’t flip a coin. Instead, think of central A/C as two separate systems, controlled by a single thermostat. The cooling part actuates the compressor and begins extracting heat from indoor air. The air circulation part starts the blower fan that moves cooled air through the ductwork to all rooms in the house. Depending on the thermostat setting, you can have air circulation only while the system’s cooling — or you can have it all the time.
Which is better?
Depends on your priorities. Here are some pros and cons:
In auto mode the blower fan starts when the thermostat signals the compressor to cycle on. Both functions operate until the thermostat temperature setting is reached, then both cooling and air circulation stop simultaneously. The main advantage of auto mode is economy: Shutting down the blower with the rest of the system lowers operating costs. On the other hand, air filtration ceases, too. This may allow airborne dust and allergens to accumulate in the indoor environment until the next time the blower cycles on. On/off operation in auto mode also incurs more wear and tear, which may lead to earlier blower failure and replacement.
In on mode the blower continues to run after the compressor cycles off. Blower electricity consumption — of about 300 watts — also continues. Blower electrical use represents a meaningful part of your cooling expenses. Continuous air circulation means nonstop air filtration, however, so indoor air quality may benefit. Electric motors like the blower also tend to last longer if they run continuously versus on/off operation.
The Best Of Both
A third alternative exists: Upgrading your system to a continuous variable-speed blower that runs across a range of programmed output but defaults to very low, energy-efficient speed most of the time. Air filtration is continuous yet the electronically commutated motor (ECM) technology consumes about 75% less electricity than a conventional blower.
Ask the professionals at Paitson Bros. about the optimum thermostat setting for your home. We’ve been advising Wabash Valley homeowners about comfort and efficiency since 1922.
Our goal is to help educate our customers in Terre Haute, Indiana about energy and home comfort issues (specific to HVAC systems). For more information about thermostat settings and other HVAC topics, download our free Home Comfort Guide or call us at 812-645-6859.
Credit/Copyright Attribution: “doomu/Shutterstock”
Jeff Paitson is a third generation business owner who continues to run the business with the same values that have been passed down from previous generations since 1922.
Jeff’s belief is that the business belongs to Jesus Christ; therefore 10 percent of the company’s profits go toward the Maryland Community Church.
Jeff is a Terre Haute Chamber of Commerce member and in his spare time, he enjoys 
Ethan Rayburn is a lifelong resident of Terre Haute and a 2005 graduate of Purdue University.
An Eagle Scout, Ethan spent four years as a non-profit executive with the Boy Scouts of America before joining Paitson Bros. as a comfort advisor and later General Manager. In that role, Ethan has brought a renewed enthusiasm for customer care, integrity, value, and service to Paitson Bros. Heating & Air Conditioning.
Ethan enjoys singing and was a member of the Purdue Varsity Glee Club. He also enjoys playing and coaching soccer, spending time with his family and two young boys, and volunteering his time and resources with his church, Terre Haute First Baptist Church, which he has attended from a very young age.
Paitson Bros
1 (812) 232-2347
Serving the Wabash Valley, IN Area Since 1922