Heating safety

01 — Space heaters

The most important space heater rule: three feet of clearance from anything that can burn.

Portable space heaters account for a significant share of heating-related home fires. The CPSC estimates portable heaters cause approximately 1,700 residential fires per year, resulting in about 70 deaths annually. The cause pattern is consistent: heaters placed too close to drapes, furniture, bedding, or clothing.

• Never leave a space heater running unattended. Turn it off before leaving the room or going to sleep.
• Plug the heater directly into a wall outlet, not an extension cord or power strip — the current draw can overheat extension cords.
• Choose a heater with an automatic shutoff for tip-over and overheating — these are now standard on most models.
• Keep space heaters away from water — bathrooms and laundry areas unless the unit is specifically rated for wet locations.
• Do not use space heaters to dry clothing.

02 — Wood stoves and chimneys

Creosote is the wood stove's hidden danger. It builds up silently inside the chimney and can ignite into a chimney fire.

Creosote is a chemical byproduct of incomplete combustion that deposits on the inner walls of a chimney flue whenever wood burns. Burning wet, unseasoned, or green wood produces far more creosote than dry seasoned hardwood. When creosote buildup is heavy enough and a hot fire is burning, the creosote can ignite into a chimney fire — a fast, very hot event that can spread to the house structure.

The CPSC and Portland Fire both recommend a professional chimney inspection and cleaning before each heating season. Inspection looks for creosote levels, cracks, blockages from bird nests or debris, and structural integrity. Cleaning removes accumulated creosote before it becomes a hazard. This is not optional maintenance for active wood stove or fireplace users.

• Burn only dry, seasoned hardwood. Seasoned wood produces more heat, less smoke, and significantly less creosote than green or wet wood.
• Never use gasoline, charcoal lighter fluid, or other flammable liquids to start a fire in a wood stove or fireplace. The vapors can explode.
• Keep a sturdy metal screen or glass enclosure in front of the fireplace to contain sparks and embers.
• Open the damper before lighting a fire and keep it open until ashes are completely cool. Never close the damper with warm ashes — CO can accumulate.
• Let ashes cool fully, then store them in a metal container with a tight lid, outside the home, away from combustible materials. Never put warm ashes in cardboard, paper bags, or plastic containers.
• NFPA standards call for 36-inch clearance between a wood stove and combustible walls.

03 — Kerosene heaters

Kerosene heaters produce carbon monoxide. They require ventilation — a slightly open window — whenever they are in use.

Unvented kerosene heaters are banned in many states and localities because they produce CO, nitrogen dioxide, and other combustion gases. Where they are used, they require ventilation because the combustion products build up in a sealed space. Opening a window slightly — just a crack — is enough to allow combustion gases to escape while still retaining most of the heat.

• Use only 1-K grade kerosene, the cleanest grade available for heaters. Never use gasoline, diesel, or other fuels — they produce excessive smoke, soot, and toxic gases.
• Refuel the heater outdoors and when the heater is completely cool. Never add fuel to a burning or warm heater — fuel vapors can ignite.
• Keep a CO alarm in the room where the heater is used. Check that it is working before the heating season begins.
• Store kerosene in containers approved for kerosene, clearly labeled, away from living areas and ignition sources.
• Never use a kerosene heater in a sleeping area — CO accumulates over hours, and a person asleep may not wake in time.

04 — Emergency heating when power is out

The safest emergency heat source during a power outage is body heat and insulation. If using fuel-burning alternatives, do so with full CO awareness.

When the primary heating system fails — due to a power outage, fuel supply disruption, or equipment failure — the instinct to bring any available heat source inside creates a serious CO poisoning risk. Charcoal grills, propane camping stoves, gasoline generators, and outdoor gas heaters all produce CO in concentrations that can be fatal in an enclosed space within minutes to hours.

Safe emergency heating options: consolidate people into one well-insulated interior room; layer clothing, use sleeping bags, and cover with blankets; use electric space heaters if electricity is available; use a properly installed and vented wood stove or fireplace; use a propane or kerosene heater with a cracked window and a working CO alarm in the room. If using any fuel-burning heater indoors, ensure CO alarms are functioning and positioned in the room.