When wildfire season arrives in Southern California, staying warm often competes with staying healthy. Smoke from regional fires can seep indoors and degrade air quality, even when windows are closed and you are sheltering inside. That matters because wildfire smoke has become a major driver of fine-particle pollution. Recent research finds that wildfires now contribute up to 25% of total PM2.5 across the U.S. and as much as half in parts of the West, which includes California.
In that context, many homeowners reach for a space heater on cold, smoky days. Used correctly, modern heaters can take the edge off a room. Used carelessly, they can add to the danger. Federal safety data show that portable space heaters are involved in an average of about 1,700 residential fires each year in the U.S., leading to roughly 70 deaths and 160 injuries. Heating equipment overall remains a significant winter fire risk, with space heaters and heating stoves linked to nearly one-third of home heating fires.
This article unpacks what that means during wildfire events: how smoke affects indoor air, what different heater types actually do, where the real risks lie, and how to warm a space without compromising your family’s safety. Along the way, we will point you to practical upgrades that improve resilience and comfort, like high-efficiency filtration, envelope sealing, and smart layout changes.
If you are considering a significant upgrade—such as adding a flexible living space that can double as a safe, well-sealed retreat—explore our in-house ADU builder services. Our Resource Center is updated with field-tested guidance for homeowners planning improvements for comfort, safety, and value; start here: FTR Renovation & Build Blog. And if you want to see how thoughtful design and careful construction help families recover after a disaster, read our Pacific Palisades story: See how intelligent design can rebuild a life. We bring the same care, code knowledge, and craftsmanship to every project so you can rely on FTR as your go-to partner for fire-aware remodeling and rebuilding in Southern California.
Understanding the Risks: How Wildfires Affect Indoor Air Quality
Wildfire smoke can infiltrate even well-sealed homes and elevate indoor PM2.5 to unhealthy levels, irritating eyes and airways and aggravating heart and lung conditions. During smoke events, the EPA recommends creating a “clean room,” keeping windows closed, setting HVAC to recirculate, and using an appropriately sized portable air cleaner.
CARB also advises upgrading to the highest MERV filter your system can handle (ideally MERV 13+) and using a CARB-certified purifier. These steps can cut indoor smoke particles substantially—real-world interventions with portable air cleaners commonly reduce indoor PM2.5 by about 50–60%.
Quick checks for smoky days
- Close windows and exterior doors; set HVAC/mini-split to recirculate.
- Run a portable HEPA purifier sized to the room (check Clean Air Delivery Rate).
- Limit indoor particle sources (no candles, wood fires, smoking).
Pro tip: If supplies are tight, a DIY purifier (Corsi-Rosenthal box) is a low-cost stopgap many communities have used effectively during heavy smoke.
Space Heaters 101: Types and Functionality Explained
Most homeowners consider two categories:
- Electric heaters (ceramic, oil-filled, panel, or infrared): No combustion, so no indoor CO emissions; look for tip-over protection, overheat shutoff, and a thermostat.
- Fuel-burning heaters (propane/kerosene): These produce carbon monoxide and other combustion byproducts. They require ventilation that is often incompatible with keeping smoke out, and in California, unvented indoor gas heaters are prohibited for sale.
FTR insight: In smoke season, we typically recommend electric options indoors. If you use any fuel-burning appliance, ensure working CO alarms on each level and outside sleeping areas. CDC
The Safety Concerns: Can Space Heaters Increase Fire Risks During Wildfires?
Yes—misused heaters can add an avoidable fire risk during an already risky period. National fire data show heating equipment fires peak in winter, and space heaters and heating stoves are involved in roughly 29% of home heating fires. Keeping combustibles too close and improper electrical connections are common factors.
What makes heaters hazardous
- Clearance: Anything that can burn (bedding, curtains, furniture) should be kept close to the heater.
- Power: Extension cords/power strips that overheat under high current.
- Supervision: Running heaters unattended or while sleeping.
The CPSC urges a 3-foot safety zone and says to plug heaters directly into a wall outlet—never an extension cord or power strip.
Pro tip: If your room needs multiple extension cords to place a heater, the layout isn’t safe. Reposition the heater or choose a different heat source.
Best Practices for Using Space Heaters Safely During Wildfire Conditions
Do this every time
- Keep a 3-foot buffer around the heater; never drape clothes or towels over it.
- Plug directly into a wall outlet; do not use power strips or extension cords.
- Choose models with tip-over and overheat shutoff and a thermostat; look for UL/ETL marks.
- Turn it off before bed and when leaving the room.
- During smoke events, keep HVAC on recirculate and use MERV-13 filters or better. Supplement with a HEPA purifier in occupied rooms.
- Monitor AQI (AirNow or a calibrated local sensor map) to time ventilation when outside air improves.
Pro tip: Make one bedroom your clean room. Seal obvious gaps, run a correctly sized purifier continuously, and heat that room rather than the whole house. It’s more comfortable and uses less energy.
Quiet nudge from FTR: If smoke intrusion is a recurring issue, we can help with envelope sealing, dedicated filtration, and safe heating layouts as part of a remodel or ADU build. Explore our ADU builder services and see practical guides in our Resource Center.
Alternatives to Space Heaters: What to Use When Wildfires Strike?
When outdoor air is hazardous, consider warmer-by-design solutions that don’t add combustion risks:
- Central heat or ductless mini-splits set to recirculate with MERV-13 or better filtration. In Southern California’s mild climate, heat pumps are exceptionally efficient and provide year-round comfort.
- Portable HEPA air cleaners + modest electric heat: Clean the air while taking the edge off the temperature.
- Electric heated throws/blankets and heating pads for personal warmth; follow safety guidance to prevent overheating and cord damage.
Pro tip: If you’re already planning a garage conversion or ADU, FTR can design a tight, filtered “safe retreat” with a high-efficiency heat pump and balanced ventilation—comfortable in smoke season without opening windows. See how we approach recovery-focused design in our Pacific Palisades post-fire remodeling story.
Making Informed Decisions About Space Heater Usage During Wildfire Season
Space heaters can be part of your plan during wildfire season, but they require disciplined setup: 3-foot clearance, wall-outlet power only, and active air cleaning. For many families, the most resilient path is upgrading the building itself—sealed envelopes, right-sized filtration, and efficient heat pumps—so you stay warm and breathe cleaner air even when smoke lingers. If you’re exploring an ADU or a larger remodel, our team at FTR Renovation & Build is here to design solutions that protect comfort, health, and value in every season. Visit our Resource Center or start a conversation through our ADU builder page.