Should You Run Your AC During Wildfire Smoke in Sacramento?

When smoke reaches the Sacramento region, shutting off the air conditioner is not automatically the right answer. Keeping the house cool matters, too. The useful question is whether your system can cool and filter indoor air while limiting smoke coming in from outside.

This is a preparation guide for Sacramento-area households—not a current air-quality alert. Check your address on AirNow and follow local emergency instructions before deciding what to do.

Start with your system’s air settings

EPA recommends keeping windows and doors closed during smoke events while maintaining a safe indoor temperature. For central HVAC with a controllable outdoor-air intake, follow the manufacturer’s instructions for recirculation or temporarily closing that intake. If you cannot identify the control, ask for help rather than guessing. Never obstruct a combustion-air opening or appliance exhaust.

EPA also recommends running the central fan in its “On” setting during smoke events when using an appropriate high-efficiency filter. That setting circulates air through the filter between cooling cycles; it does not mean lowering the temperature setting. See EPA’s wildfire and indoor-air guidance.

Choose a filter your HVAC system can handle

EPA recommends MERV 13 or higher for smoke filtration, with a professional determining what your system can accommodate. Compatibility and fit matter: do not assume the highest-rated filter will work in every system. Inspect it frequently during smoke and replace it when dirty. Ask an HVAC professional if you are unsure about allowable filtration or airflow. See EPA’s smoke-preparation guidance.

Before calling, write down the filter’s printed size and rating, the thermostat model, and where the filter is located. A photo of an accessible label can make the conversation more useful; there is no need to open equipment cabinets.

Prepare one cleaner-air room

A room where your household can spend time together gives you another option. EPA recommends a correctly sized portable air cleaner that does not generate ozone. Keep that room’s windows and doors closed, run the cleaner as directed, and avoid indoor particle sources such as candles, smoking, and frying food.

Do not let a closed-up home become dangerously hot. If you cannot keep cool, power fails, or smoke remains excessive indoors, seek a safer location. A cleaner-air room is not a substitute for an evacuation order. See EPA’s clean-room guidance.

Questions to keep beside your thermostat

Prepare a short household note before smoky conditions arrive:

• What filter size and rating has been approved for this system?
• Is there an outdoor-air control, and who has shown us how to use it?
• Where are the operating instructions and replacement filters?
• Where could we go if the house cannot stay cool?

For a Sacramento, Elk Grove, or Folsom home, the answers should describe the equipment at that address—not a generic setting copied from a neighbor’s thermostat.

Frequently asked questions

Does turning the thermostat lower remove more smoke?

A lower temperature target is not a substitute for filtration. EPA’s smoke guidance focuses on limiting outdoor smoke entry and filtering indoor air, including using the appropriate fan setting. Read the guidance.

Can a portable cleaner replace an evacuation plan?

No. A cleaner-air room is a way to reduce exposure while sheltering indoors, not permission to stay when authorities direct you to leave. EPA clean-room guidance.

What should I tell the HVAC company?

Give your service address, equipment type if known, filter information, and the concern: an unfamiliar ventilation control, filter-fit question, or difficulty keeping the house comfortable. Mention what you have already changed so the technician has a clear starting point.

Ask about your home’s HVAC setup

Capital City Comfort provides residential and commercial HVAC repair, maintenance, installation, and replacement throughout Sacramento and surrounding communities and is open 24/7. Call (916) 390-0025 or request service to discuss your equipment and confirm availability for your address. Availability varies by equipment, project, and scheduling.