Small portable heaters can provide localized or emergency heat for homes, cottages and service buildings. Kerosene heaters require good judgment and safety practices. This publication answers typical questions about kerosene heaters, lists positive and negative aspects, and suggests practices to follow when using a portable unvented heater.

What are the hazards of using these heaters in homes?

This type of heater produces an open flame in a confined area, which creates three recognized hazards. It:

• lowers the quality of the air you breath by reducing available life-sustaining oxygen and increasing poisonous carbon monoxide;

• increases the risk of burns from direct contact or from ignition of aerosol sprays, lacquers, or other flammable gases; and

• increases the risk of fire.

Do I really have to have an open window or keep a door ajar to use these heaters safely?

Yes, you really should provide outside air. According to the Canadian Standards Association, ventilation should be four times greater per 1,000 Btu/hr for unvented heaters than for vented heaters. Furnaces connected to chimney flue draw outside air into the house (by infiltration) as air moves up the chimney. Unvented heaters do not. Providing outside ventilation is a reason for concern since we try to make our homes airtight.

Opening a door to an adjacent room may not provide enough ventilation in an airtight house with very low air exchange rates. This could result in dangerous levels of carbon monoxide (CO) and other by-products of combustion. Battery-operated CO detectors with alarms will alert you to dangerous levels of CO, and should be installed in any enclosed area where a kerosene heater is being operated.

What is carbon monoxide?

Carbon monoxide is a colorless, odorless, and poisonous gas that can build up in your blood cells as you breathe. It may reach toxic levels in minutes or over several hours. Early symptoms of poisoning include dizziness, headache, and/or nausea.

People who are sleeping are likely to be more susceptible to carbon monoxide poisoning since they will not recognize the symptoms. Just getting out in the open air doesn’t eliminate carbon monoxide from your body. It takes 10 to 24 hours, so suffocation may even occur after you have left areas with high levels of carbon monoxide.

If I store fuel in an unheated area, such as a garage, will this create a problem?

Yes, it can. As the fuel warms, it expands. Since it has nowhere to go, excess fuel is pushed into the burn chamber. This can create a flame larger than the unit can contain and result in a house fire. Remember, when refueling, do not fill the heater’s fuel tank completely since cold kerosene expands as it warms.

Guidelines for Choosing Portable Kerosene Heaters

When selecting a portable kerosene heater, here are some guidelines:

• Be sure the heater design will not allow flooding of the burner. Models with a wick meet this requirement.

• Ask your dealer to demonstrate what happens if the heater is jarred or tipped over. Heaters suitable for home use should have a safety shut-off device that automatically snuffs out the flame if the heater is tipped. No significant amount of kerosene should spill if the heater is laid on its side.

• The heater should have a low center of gravity to make accidental tipovers unlikely.

• Check construction for durability. The heater should be made of heavy-gauge steel and have such features as double walls for protective grills to guard against contact burns.

• The fuel feed should be located below the burner. The fuel should be contained in a sturdy tank that will not shatter and spill fuel if dropped.

• A fuel gauge should be provided to prevent overfilling or unnecessary refilling. A siphon pump provided with a kerosene heater will help prevent accidental refueling spills.

• Check for a push-button lighting device that eliminates the need for matches.

• Burner design should provide such complete and efficient combustion that there should be no detectable odor or smoke during operation.

• Have your dealer demonstrate lighting and operating procedures.

• Approval by a recognized testing laboratory, such as Underwriters Laboratories, can provide additional assurance that the heater has performed well under their test conditions and meets some safety standards.

• Check manufacturer’s literature for BTU ratings of various models. Discuss with your dealer the appropriate size unit for the area you wish to heat.

• Check local codes for permitted uses.

Using a Kerosene Heater

• Use only those heaters that have "Underwriters Laboratories listed" (U.L. listed) on the nameplates.

• Read manufacturer’s instruction booklet carefully and follow directions for operation and maintenance. Read and heed warning decal messages, typically placed on the back of the heater.

• Open a window to provide ventilation when a portable kerosene heater is in use.

• Use "clear white," l-k grade, kerosene only. Never substitute fuel oils, diesel, any type of gasoline, or yellow (regular) kerosene.

• Install smoke detectors and residential CO detectors in the home.

• Always refuel the heater outside with the unit off. Do it in an area where small spills can be quickly cleaned up. Avoid carpets or vinyl surfaces. Carpets absorb odor, and vinyl will deteriorate from spills. Never refuel inside or while heater is in operation.

• Place heater away from curtains, drapes, bedding, books, papers, furniture, or other flammable material.

• Prevent children from coming in contact with the heater by instructing and/or by guarding it with a barrier. Do not use in areas where dogs or other pets could tip the unit over.

• Inspect the heater for leaks and access carbon every time you refuel. Clean and maintain according to the manufacturer’s instructions.

• When turning heater off, be sure flame goes out.

• Do not use hairspray and other flammable aerosol sprays, lacquers, and flammable liquids in an area where these heaters are used. Kerosene heaters, water heaters, and similar units will ignite vaporized fuels.

• Store kerosene in a tool shed or other out building in an area away from open flames or spark ignition points. Never store kerosene in a home basement.

• When refueling, do not fill the heater’s fuel tank completely since cold kerosene expands as it warms. Follow the manufacturer’s instructions regarding the length of time the refueled tank should stand at room temperature before the heater is used.

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Source: "Safety Notes: Unvented Portable Kerosene Heaters," W. Lilley, University of Maine Cooperative Extension Service, 1987. Reviewed by John W. Donovan, Extension educator.

For more information on emergency preparedness, contact your county UMaine Extension office.

©1998
Published and distributed in furtherance of Acts of Congress of May 8 and June 30, 1914, by the University of Maine Cooperative Extension, the Land Grant University of the state of Maine and the U.S. Department of Agriculture cooperating. Cooperative Extension and other agencies of the U.S.D.A. provide equal opportunities in programs and employment.