Should You Switch Off Your AC When Not Home? Expert Opinions

Air conditioning offers a welcome relief during scorching hot periods, but there’s an ongoing discussion about whether it’s wiser to switch off your AC when you leave home for a while.

Some individuals staunchly believe that shutting down the air conditioner when out even for a brief period is the optimal way to conserve energy and cut costs. Conversely, others assert that leaving it constantly running ensures the unit doesn’t need to exert extra effort to cool the home upon return.

According to three specialists consulted by The Associated Press, a suitable middle ground is to slightly increase your thermostat setting when away for a more energy-efficient balance between coolness and humidity control.

While deactivating your AC for extended durations can be more economical and energy-saving, this strategy might fuel mold concerns in moist zones and accelerate wear leading to more repairs. This balance varies based on factors like comfort preference, AC type, and building insulation.

Residential and commercial air conditioning in America uses up to 7% of the entire national energy consumption, as highlighted in a study co-authored by Phelan. Furthermore, a 5.5% jump in electrical costs was noted by the recent Consumer Price Index from the U.S. Bureau of Labor Statistics in July compared to the previous year.

Considering Climate Conditions

The U.S. Energy Department reveals that a daily temperature adjustment of 7-10 degrees Fahrenheit over eight hours could save nearly 10% yearly on heating and cooling expenses.

Specialists emphasize a variety of elements influencing energy and cost efficiency in AC practices.

"If you're just out for a brief errand, like a quick grocery run, turning off the AC offers no real advantage," states Elizabeth Hewitt, an urban planning scholar from Stony Brook University.

However, for full workdays circling about eight hours, "you'll frequently conserve more on energy bills by simply turning it off," she advises.

Nevertheless, in certain environments, shutting down the AC might not suffice, recommending instead a modest thermostat increase to prevent sustained cooling all day long.

In arid locals like Arizona, allowing the home to warm slightly by raising the thermostat is feasible. Conversely, in humid regions such as Florida, an extended AC shutdown could invite mold due to insufficient moisture management by the system.

Adjusting the thermostat by a single degree Fahrenheit translates to cooling savings of roughly 3%, says Patrick Phelan, a mechanical engineering expert at Arizona State University.

Moreover, Phelan notes, deactivating AC systems for hours only to reactivate later tends to increase wear, necessitating more frequent upkeep. That's because such systems need about 15 to 30 minutes post activation to function at peak efficiency.

Impact of Home Structure

Your residence’s construction plays a crucial role in the extent of energy and monetary savings achievable, explains Gregor Henze, an architectural engineer from the University of Colorado Boulder.

Homes made with denser materials like concrete or brick maintain cooler air longer, while older, draft-prone houses warm quickly.

In homes with minimal insulation, even brief absences merit thermostat adjustments due to rapid indoor temperature changes, Henze advises.

AC Units and Thermostats

The energy savings you gain might vary based on whether you own a window unit, smart thermostat, or central air system.

Generally, window AC units are less efficient as they are installed in unrestricted windows, making it tough to seal out warm air thoroughly, notes Hewitt. She suggests using inexpensive foam spray insulation for sealing drafty spots as a cost-effective method to preserve indoor temperatures.

Phelan mentions that smart thermostats alleviate the hassle of manually adjusting settings multiple times daily. These devices learn occupancy patterns using sensors, adjusting temperatures accordingly to conserve energy when no one’s home.

"Switching from a regular manual thermostat to a smart model like a Nest could yield savings of up to 10%," Phelan states.

Additional Cooling Strategies

Simple measures like filtering sunlight have significant effects on home cooling, according to each expert.

Henze highlights well-worn techniques such as keeping windows open during cooler nights. In drier settings, this introduces little moisture, but in humid areas, the added dampness could pose a challenge as the AC balances it later.

Hewitt further mentions that shutting blinds can offer degree-level temperature changes. Phelan adds that sun-reflective blinds or tinted window films are also effective.

Ceiling fans are beneficial, instinctive for counterclockwise rotation in summer to push warm air downward and create a refreshing breeze. For autumn and winter, the rotation should revert clockwise to circulate rising warm air, as stated by Laurie Wheelock, New York's Utility Project’s executive director.

Houseplants can provide valuable shade, and minimizing oven use further aids in maintaining a cooler interior, experts suggest.