Can You Leave Your AC on While on Vacation? Here’s the Best Setting

Many homeowners face this dilemma before heading out on vacation: “Should I turn off my AC to save on energy bills, or keep it running?” It’s a common question, especially during Los Angeles summers when energy costs can spike and every dollar counts.

The short answer might surprise you: yes, you should leave your AC on while away, but at a higher temperature setting. Extreme heat and humidity can cause serious damage to your home, belongings, and even your HVAC system itself. The key is finding the right balance between energy efficiency and home protection.

Using local expertise and proven strategies, this guide will help you determine the optimal thermostat setting for your LA home while you’re away, ensuring you return to a comfortable space without breaking the bank.

Why Leaving Your AC On Actually Matters

Humidity Control and Mold Prevention

Your HVAC system does more than just cool the air—it actively manages indoor humidity levels. When you turn off your AC completely, moisture can quickly build up, creating the perfect environment for mold and mildew growth. This is particularly concerning in areas with higher humidity, but even LA’s relatively dry climate can experience humidity spikes.

Mold doesn’t just create unpleasant odors; it can cause structural damage to your home and pose serious health risks. Wood fixtures can warp, drywall can deteriorate, and once mold takes hold, removal can be expensive and time-consuming.

Protecting Your Belongings

Electronics, wooden furniture, musical instruments, and even food items are vulnerable to extreme temperature fluctuations. Heat can cause electronics to malfunction, wood to crack or warp, and perishable items to spoil faster than expected. If you have houseplants, they’re also at risk in an overheated home.

The cost of replacing damaged belongings often far exceeds the energy savings from turning off your AC entirely.

Avoiding System Strain

When you return from vacation to a sweltering house, your AC must work overtime to bring the temperature back down to a comfortable level. This sudden, intense workload puts significant strain on your system, potentially leading to breakdowns and reducing its overall lifespan. The energy required to cool an extremely hot house often exceeds what you’d use to maintain a moderate temperature while away.

Best Thermostat Settings While on Vacation

General Expert Recommendations

HVAC professionals consistently recommend raising your thermostat by 7-10°F above your normal setting when leaving for vacation. If you typically keep your home at 72°F, setting it to around 79-82°F strikes the right balance between energy savings and home protection.

For most vacation scenarios, the ideal range falls between 78°F and 82°F for short trips. For extended stays of two weeks or longer, you might push it to 85°F, but this should be the absolute maximum to prevent damage.

Local Insight for Los Angeles Homes

Los Angeles benefits from a Mediterranean climate with generally lower humidity than many other regions, but this doesn’t mean you should turn off your AC completely. The city’s summer temperatures can still reach the 90s, and inland areas often exceed 100°F.

For LA homeowners, targeting around 78°F during summer vacations provides optimal efficiency. This setting accounts for the region’s dry heat while ensuring your home stays protected. The relatively mild evenings help reduce the system’s workload, making this temperature both practical and economical.

Always keep your AC running during longer absences, even in LA’s dry climate. Humidity control remains essential for preventing damage and maintaining air quality.

When It Might Be Okay to Turn Your AC Off

Very Short Absences

If you’re only leaving for a few hours, the energy savings from adjusting your thermostat are minimal. Your system uses more energy cycling on and off frequently, so maintaining a consistent temperature is often more efficient for brief outings.

Extended Vacations with Ideal Conditions

In rare cases, you might consider turning off your AC for extended periods if your home has exceptional insulation and you’re traveling during cooler months. However, this approach carries significant risks and generally isn’t recommended, even for well-insulated LA homes.

The potential for unexpected weather changes, humidity buildup, or system issues makes this strategy too risky for most homeowners.

Smart Strategies for Maximum Efficiency

Programmable and Smart Thermostats

Modern thermostats offer the perfect solution for vacation temperature management. You can program automatic setbacks for your departure and schedule the system to cool your home before you return. Smart thermostats even allow remote monitoring and adjustments via smartphone apps.

These devices pay for themselves through energy savings and offer peace of mind through remote monitoring capabilities.

Optimize Your Fan Settings

Set your thermostat fan to “Auto” instead of “On” before leaving. The “Auto” setting runs the fan only when cooling is needed, reducing energy consumption and preventing unnecessary humidity circulation.

Prepare Your Home for Departure

Close blinds and curtains to block solar heat gain, seal any air leaks around windows and doors, and consider unplugging non-essential electronics to reduce internal heat generation. These simple steps can significantly improve your AC’s efficiency while you’re away.

Expert Takeaways for LA Homeowners

The smartest approach for Los Angeles homeowners is to set your thermostat to “Auto” cooling mode with a temperature around 78°F for most summer vacations. Never turn your AC completely off, regardless of the season or duration of your trip.

A 7-10°F setback from your normal temperature provides substantial energy savings without risking damage to your home or belongings. For maximum convenience and control, investing in a programmable or smart thermostat offers long-term benefits beyond just vacation settings.

Make the Smart Choice for Your Home

Leaving your AC on at a higher setting while on vacation protects your investment, saves money in the long run, and ensures you return to a comfortable home. The energy savings from this approach, combined with avoiding potential damage costs, makes it the clear winner over turning your system off entirely.

Ready to optimize your home’s comfort system? Consider upgrading to a smart thermostat or scheduling a consultation to ensure your HVAC system is running at peak efficiency for both daily use and vacation settings.