Any heater that burns fuel—such as natural gas, propane, kerosene, or wood—can leak carbon monoxide (CO). Electric heaters do not produce or leak carbon monoxide.
Carbon monoxide (CO) poisoning is caused exclusively by fuel-burning heaters that rely on combustion. Any heater that burns gas, oil, wood, kerosene, or coal produces CO and poses a risk if it is unvented, poorly ventilated, malfunctioning, or used improperly.
Common signs of a carbon monoxide leak include:
The safest heaters to leave on overnight are permanently installed electric baseboard heaters or portable oil-filled radiant heaters. Because the heating element is fully enclosed and submerged in oil, these models do not get red-hot, lack exposed coils, and are much less likely to ignite nearby bedding or curtains.
The most common cause of carbon monoxide (CO) leaks is the improper ventilation, incorrect installation, or poor maintenance of fuel-burning appliances. When appliances like furnaces, ovens, and water heaters do not burn fuel completely or their vents are blocked, dangerous, odorless CO gas builds up indoors.
It is also a good idea to know the signs of a potential CO problem:
The greatest sources of CO to outdoor air are cars, trucks and other vehicles or machinery that burn fossil fuels. A variety of items in your home such as unvented kerosene and gas space heaters, leaking chimneys and furnaces, and gas stoves also release CO and can affect air quality indoors.
Sealed combustion heaters are much safer to operate than other types of space heaters, and operate more efficiently because they do not draw in the heated air from the room and exhaust it to the outdoors.
The baseboard heaters or electric boilers in your home aren't giving off carbon monoxide or carbon dioxide or any other emissions, but there's far more to consider than what's going on in your home.
Consumer Reports tests space heaters primarily on room heating ability, spot heating, and strict fire and safety criteria, such as overheat protection and tipping tests. Highly rated models often cost around $75 to $100 and feature auto-climate control and tip-over shut-offs.
One of the most common early symptoms of carbon monoxide (CO) poisoning is a headache, often described as dull or persistent. Because CO is odorless and colorless, these early signs are frequently mistaken for the flu or food poisoning.
Any furnace that burns fuel produces carbon monoxide as a byproduct. This is the same for any appliance in your home that burns fuel, such as a gas range. Therefore, if your furnace uses natural gas, propane, or oil to make heat, your furnace creates carbon monoxide. Electric furnaces do not create carbon monoxide.
Symptoms of Carbon Monoxide Poisoning
Low levels of CO poisoning can be confused with flu symptoms, food poisoning or other illnesses and can have a long-term health risk if left uncorrected.
The term "silent killer gas" almost universally refers to Carbon Monoxide (CO). It is a colorless, odorless, and tasteless gas produced by the incomplete burning of fossil fuels (like wood, coal, propane, and gasoline). It is deadly because it replaces oxygen in your bloodstream, preventing vital organs from functioning.
Breathing high levels of CO can cause sudden illness or death in a matter of minutes. Gas- and oil-burning furnaces produce CO, an invisible, odorless, poison gas that kills hundreds every year and makes thousands more, sick.
Carbon monoxide (CO) poisoning is often called the "silent killer" because the gas is completely invisible and odorless. Because its symptoms closely mimic the flu or a common stomach bug, it is highly dangerous.
The safest space heaters are oil-filled radiators and modern ceramic heaters with built-in safety features like tip-over sensors, automatic overheat shutoff, and cool-touch exteriors. Always choose models that are ETL or UL certified and keep them at least three feet away from flammable items.
You do not need to worry about carbon monoxide (CO) with electric heat because electric heaters do not rely on combustion. Because no fuel is burned to create warmth, it is physically impossible for a properly functioning electric system to emit CO.
Best for small rooms → Fan heaters are a handy choice when you want quick warmth in spaces like bedrooms, studies or bathrooms. Best for larger rooms → Panel heaters and oil column heaters are better suited to bigger living spaces where you want steady, comfortable warmth.
The safest heaters to leave on overnight are permanently installed electric baseboard heaters or portable oil-filled radiant heaters. Because the heating element is fully enclosed and submerged in oil, these models do not get red-hot, lack exposed coils, and are much less likely to ignite nearby bedding or curtains.
Are infrared heaters safer than ceramic heaters? Yes. Infrared heaters have no exposed heating elements or fans, reducing fire hazards. Also, since they don't circulate air, they don't circulate allergens.
Space heaters are involved in an estimated 1,700 residential fires and cause approximately 70 to 80 deaths annually in the U.S.. While they make up a small fraction of all home fires, they are highly lethal—accounting for over 40% of home heating fires and nearly 85% of home heating fire deaths.
Sooty or yellow/brown stains on or around boilers, stoves, or fires. Smoke building up in rooms. Yellow flames coming out from gas appliances except at natural gas fireplaces. The pilot lights blow out frequently.
Carbon monoxide poisoning is the suspected cause in the death of 76-year-old Dayle Haddon, a Canadian supermodel best known for being the face of the makeup brand L'Oréal. Haddon died Friday at the Solebury Township, Pennsylvania home of her actor son-in-law, Marc Blucas.
Because carbon monoxide (CO) is a colorless, tasteless, and odorless gas, it is impossible to detect with human senses. The only reliable way to know if it is in your air is by using a certified Carbon Monoxide Detector.