Safe heating vs. deadly carbon monoxide

Carbon monoxide (CO) is an invisible, completely odorless gas produced whenever fuel burns without enough ventilation. You cannot see it, smell it, or taste it— you simply feel dizzy or sleepy and never wake up.

If you only do three things

1. Run portable generators OUTSIDE only, at least 20 feet (6 meters) away from every window, door, and vent—never inside a garage, even with the garage door open.
2. Never use a gas kitchen oven, gas stovetop burners, charcoal grill, or camping stove to heat your living space.
3. Keep space heaters at least 3 feet (1 meter) away from curtains, bedding, and furniture, and plug them directly into the wall outlet (never an extension cord).

What is DEADLY indoors vs. what is SAFE indoors

• DEADLY INDOORS: Portable gasoline/propane generators, charcoal grills, hibachis, camping stoves, outdoor patio heaters, and running a car inside an attached garage.
• DANGEROUS INDOORS: Leaving a gas kitchen oven door open for heat (ovens are not vented to the outside and quickly build up lethal carbon monoxide when run continuously).
• DANGEROUS MYTH — Terracotta Flower Pot & Tea-Light Candles: Viral social media posts claim an upside-down clay pot over four tea-light candles will 'heat a room for pennies.' In reality, 4 tea-lights produce only about 120 watts total (less than two people sitting in a room), cannot raise room temperature noticeably, and frequently melt the wax pool into an explosive paraffin grease fire.
• SAFE INDOORS: Extra clothing layers, sleeping bags, indoor tents, hot water bottles (if you can heat water safely), wood-burning fireplaces with an open chimney damper, and UL-listed 'Indoor-Safe' cabinet propane heaters (like a Mr. Heater Buddy) that have a built-in low-oxygen shutoff sensor—always used with a battery CO alarm and a window cracked 1 inch.

Related guides

• What to do when power goes out: The One Warm Room micro-climate strategy.
• Draining pipes and saving food in a blackout: Preventing burst pipes when indoor heat fails.