Should You Leave Your AC Unit Running When You Aren’t Home?

ACE Home Services - Thermostat

Updated 7/3/2024

The age-old question of whether to turn off your air conditioning when you’re not at home is one that many homeowners grapple with. Contrary to popular belief, leaving your AC on while you’re away can actually save you money and protect your home from various issues. This comprehensive guide will explore the reasons why keeping your AC running is often the best choice, as well as provide tips on how to optimize your AC usage for both comfort and efficiency.

The Benefits of Leaving Your AC On

1. Energy Savings

While it may seem counterintuitive, leaving your AC on can lead to energy savings:

  • Increase the temperature by 7-10 degrees when you’re away
  • For absences longer than 8 hours, this can reduce energy costs by up to 10%
  • Maintaining a consistent temperature is more efficient than cooling down a hot house

2. Humidity Control

One of the key reasons to leave your AC on when away is humidity control:

  • Air conditioning systems not only cool the air but also remove moisture
  • Consistent humidity control prevents:
    • Mold growth
    • Mildew formation
    • Wood damage and warping
    • Peeling paint
    • Water stains on walls and ceilings
    • Rusting of appliances and fixtures

turning off ac while at work

3. Home Protection

Leaving your AC on protects various aspects of your home:

  • Prevents extreme temperature fluctuations that can damage structural elements
  • Maintains air circulation, reducing the risk of stagnant air and associated problems
  • Protects electronic devices and appliances from heat damage

4. Comfort Upon Return

Keeping your AC running ensures a comfortable environment when you return home:

  • Avoid walking into a hot, stuffy house
  • No need to wait for the house to cool down
  • Immediate comfort after a long day or trip

Reasons Not to Turn Your AC Off Completely

1. Overworking Your Refrigerator

When your home overheats, it affects more than just your comfort:

  • High temperatures force your refrigerator to work harder
  • Increased energy consumption by the refrigerator
  • Risk of refrigerator breakdown or malfunction
  • Potential food spoilage

2. Structural Damage to Your Home

Excessive heat and humidity can cause severe damage to your home’s structure:

  • Swelling of doors and wooden elements
  • Cracking of plaster and drywall
  • Buckling of wood floors
  • Formation of mold and mildew in hidden areas
  • Long-term damage that can be costly to repair

3. Food and Wine Spoilage

Heat and humidity don’t just affect your home’s structure:

  • Increased risk of food spoilage, even in pantry items
  • Wine corks can pop out due to high temperatures
  • Potential for mess and wasted groceries upon return

Optimal Temperature Settings When Away

To balance energy efficiency and home protection, follow these guidelines:

  • Set your thermostat 7-10 degrees higher than your normal setting
  • Aim for a temperature range of 80-85°F (26-29°C) when away
  • For shorter absences (a workday), a slightly lower setting may be preferable
  • Consider your home’s insulation and external temperature when deciding

Considerations for Pet Owners

If you have pets at home, their comfort and safety should be a priority:

  • Keep the temperature no higher than 78-80°F (25-27°C) for most pets
  • Ensure proper ventilation and air circulation
  • Provide multiple water sources for your pets
  • Consider your pet’s breed, age, and health when setting the temperature
  • Consult with your veterinarian for specific recommendations

Leveraging Smart Thermostat Technology

Programmable and smart thermostats offer convenient solutions for managing your AC:

Features of Smart Thermostats:

  • Automatic temperature adjustments based on your schedule
  • Remote control via smartphone apps
  • Learning capabilities to optimize energy usage
  • Integration with other smart home devices

Using Vacation or Hold Mode:

  • Many programmable thermostats offer a “Vacation” or “Hold” mode
  • Easily set a higher away temperature for extended periods
  • Automatically returns to normal schedule upon your return
  • Ensures consistent energy savings without daily adjustments

The Importance of Humidity Control

Controlling humidity is crucial for protecting your home and health:

Ideal Indoor Humidity Levels:

  • Aim for a relative humidity between 30-50%
  • Use a hygrometer to monitor humidity levels

Risks of High Indoor Humidity:

  • Mold and mildew growth
  • Dust mite proliferation
  • Warping of wood furniture and floors
  • Peeling paint and wallpaper
  • Water stains on walls and ceilings
  • Rusting of metal appliances and fixtures

How AC Controls Humidity:

  • Removes moisture from the air as it cools
  • Circulates air, preventing stagnant, humid pockets
  • Maintains consistent humidity levels throughout the home

Maintaining Your AC System for Efficiency

Regular maintenance ensures your AC operates efficiently:

Energy-Saving Tips for AC Use

Maximize efficiency with these additional tips:

  • Use ceiling fans to improve air circulation
  • Close blinds and curtains to block out sun during peak hours
  • Seal air leaks around windows and doors
  • Use light-colored roofing materials to reflect heat
  • Plant shade trees or install awnings to reduce solar heat gain

When to Consider Upgrading Your AC System

An older or inefficient AC system may negate the benefits of leaving it on:

  • Consider upgrading if your system is over 10 years old
  • Look for ENERGY STAR certified models for maximum efficiency
  • Evaluate the SEER (Seasonal Energy Efficiency Ratio) rating when choosing a new system
  • Consider a variable-speed or two-stage system for better humidity control and efficiency

Balancing Comfort, Protection, and Efficiency

Leaving your AC running when you’re not home is often the best choice for both your comfort and your home’s well-being. By setting your thermostat correctly and leveraging modern technology, you can protect your home from humidity damage, ensure a comfortable return, and still maintain energy efficiency. Remember to consider factors such as pets, the duration of your absence, and your specific home characteristics when making decisions about your AC usage.

Still Wondering If You Should Turn Off AC When You’re Not Home? Ask the Pros!

Contact ACE Home Services with all of your questions regarding saving money and energy. We’re also happy to provide a free quote for installing a programmable thermostat in your home or place of work.

Give us a call!

Or let us contact you!

Please enable JavaScript in your browser to complete this form.
Please confirm below

Americans with Disabilities Act (ADA) Notice

At ACE Home Services, we are committed to ensuring that individuals with disabilities enjoy full access to our websites. In recognition of this commitment, we are in the process of making modifications to increase the accessibility and usability of this website, using the relevant portions of the Web Content Accessibility Guidelines 2.0 (WCAG 2.0) as our standard. Please be aware that our efforts are ongoing. If at any time you have difficulty using this website or with a particular web page or function on this site, please contact us by phone at (602) 428-3341; or email us at ([email protected]) and place “Web Content Accessibility (ADA)” in the subject heading and we will make all reasonable efforts to assist you.

Skip to content