State University Extension
Home Maintenance And Repair - 01500603
Increases in home heating costs have helped develop a market for
portable kerosene heaters to provide localized or emergency heat for
homes, cottages and service buildings. Many questions are being asked
about the safety of these units. This publication answers typical
questions and suggests practices to follow when using a portable
unvented kerosene heater.
Questions and Answers
#1 How safe are the new unvented
portable kerosene heaters?
That depends upon who you talk to. Some public health and safety
officials take a cautious view of these types of heaters. Some
manufacturers and dealers, however, do not. But it is a fact that these
types of heaters can be a potential fire hazard and that the pollutants
these heaters produce may represent a significant health hazard.
For these reasons, some communities and some states have banned the use
of these types of heaters in homes. Would-be buyers of unvented,
portable kerosene heaters should check with building authorities and/or
fire officials and insurance representatives first.
If this type of heater is purchased, be sure to follow the
manufacturer's exact directions for operation.
#2 What are some of the hazards of using unvented, portable kerosene
This type of heater:
--- increases the potential of a home fire loss if it is placed too
close to combustibles
--- paper, curtains and other readily flammable household material
--- or is used carelessly.
--- increases the potential for personal burns. Tests by Consumer
Reports (Oct. 1982 issue) show that during normal operation, these
types of heaters can develop surface temperatures from 320 degrees F to
more than 500 degrees F. Obviously, keep small children well away from
--- produces carbon monoxide (a poisonous gas), nitrogen dioxide (which
may cause throat and lung irritation), and sulfur dioxide (which can
#3 Are there portable, unvented kerosene heaters on the market that do
not produce these gases?
No. Any heating system that burns fuel, and does not have a chimney,
will give off some gases into the room or area where it operates.
#4 Is there an accumulative "indoor pollution hazard" from use of
several unvented appliances?
It would appear so, especially in a "weatherized" home or a
Following tests of 18 types of portable, unvented heaters, Consumer
Reports states that: "We calculated the concentration of four gases
produced by these heaters --- carbon monoxide, carbon dioxide, nitrogen
dioxide, and sulphur dioxide --- in a 10x12x8-foot room with normal
ventilation. The levels of each gas were high enough to be a serious
health hazard to high-risk groups, including pregnant women,
asthmatics, people with cardiovascular disease, children, and the
elderly. The levels we calculated for some pollutants may pose risks
for healthy people."
Hazard from indoor pollution is highest on calm days when an unvented
heater is used along with an unvented gas range, gas refrigerator and a
gas clothes dryer; along with a vented water heater and furnace. Only
heating units connected to chimneys exhaust products of combustion
safely to the outside of the home.
#5 Of the gases that are produced by a portable, unvented heater, which
is potentially the most lethal?
Carbon monoxide. It is toxic because it interferes with the blood's
ability to carry oxygen to the cells of the body. It may reach toxic
levels in the blood stream within minutes or several hours. Carbon
monoxide may be a particular threat to persons with heart ailments.
Early carbon monoxide poisoning symptoms include dizziness, headache,
weakness, drowsiness and/or nausea. Some people could experience
impaired judgement and irritability.
#6 Why is carbon monoxide so deadly?
Carbon monoxide replaces oxygen in the blood until suffocation occurs.
Carbon monoxide mixes with your blood 210 times quicker than oxygen, so
even getting fresh air after poisoning symptoms begin may not help and
suffocation can still occur. It takes from 10 to 24 hours to rid the
blood of excessive carbon monoxide.
#7 Do I really have to open a window one inch or keep a door ajar to
another room to maintain a margin of safety while using a portable,
unvented kerosene heater?
Yes, especially if the heater is located in a room having less than 150
square feet. Be sure to read the manufacturer's instructions about
ventilation. The Consumer Product Safety Commission recommends one
square inch of open window in the room where the heater is being used
for each 1,000 Btu of the heater's rated output.
For example, if the heater is rated at 9,100 Btu per hour, and the
window in the room is 24 inches wide, the window should be opened
almost one-half inch. If the heater is rated at 20,000 Btu, that window
should be open almost 1 inch.
Obviously, this causes a loss of heat, but it should help provide
adequate ventilation provided that the portable heater is operating at
#8 What grade or quality of kerosene should be used?
Use ONLY 1-K grade of kerosene in portable, unvented heaters.
Kerosene is generally retailed in two grades --- 1-K, which is low in
sulfur (.04 percent sulfur by weight) and 2-K, which is much higher in
sulfur. Use of 2-K grade kerosene will dramatically increase sulfur
dioxide emissions. Using kerosene other than the 1-K grade may increase
However, finding 1-K grade kerosene may be difficult. just because a
kerosene dealer says that the grade of kerosene is "water-clear" or
"clear white" does not mean it is the 1-K grade. Both grades can look
clear. Find a dealer who can certify that what is being sold is 1-K
#9 What happens if other fuels are substituted in place of 1-K
The risk of a fire or an explosion increases dramatically. In March
1982, the Consumer Product Safety Commission and the National Kerosene
Heater Association warned against using gasoline in kerosene heaters,
citing a number of serious injuries and deaths from such use.
Other fuels, such as diesel or jet "A" fuel, may be equally dangerous.
#10 What about storing 1-K grade kerosene?
Storage of any type of liquid fuel requires a certain amount of care
and common sense. All kerosene should be stored in a metal fuel
container clearly marked KEROSENE. Paint the container green, or some
color other than red, so that it will not be accidently confused with a
container of gasoline.
Don't store kerosene in an old gasoline can. This will prevent getting
it mixed up with gasoline and inadvertently putting gasoline in the
heater. Store kerosene out of the home in a well-ventilated and cool
area, away from where children play.
#11 What safer choices do I have for spot or localized heating inside
Portable electrical heaters may also be used to conserve energy if used
to briefly warm persons in one part of the house instead of turning on
the furnace. Use portable electric heaters rated no higher than 1500
watts to avoid overloading ordinary outlets in the home. Check for the
"U.L. listed" statement on the nameplate before buying. Radiant heat
types (quartz-nichrome wire enclosed in clear tubes) are more efficient
in providing warmth to persons within 3 to 10 feet, without heating the
#12 Is it cheaper to use a portable kerosene heater or a portable
electric heater for spot heating my home?
It costs about the same to operate either heater when your electrical
rate is 5 cents per kilowatt hour and you can buy 1-K grade kerosene
for $2 per gallon. A gallon of 1-K kerosene has a Btu equivalence of
approximately 40 kilowatt hours. (135,000 Btu and 3,413 Btu/KwHr). To
estimate operating costs, multiply your actual cost per kilowatt hour
by 40 to determine what you could pay for 1-K kerosene per gallon to
produce the same number of Btu's. In addition, consider comparative
purchase prices of electric and kerosene haters, maintenance costs of
both, convenience and related factors. For example, the operating costs
provided above for kerosene units does not allow for the heat lost by
slightly opening a window for ventilation, as recommended by the
Consumer Product Safety Commission and most manufacturers. Neither is
allowance made for costs new electrical outlets or circuits that might
be needed for a portable electrical heater.
#13 Should I use a portable, unvented kerosene heater in my home?
While the choice is clearly yours, consider this:
--- The National Kerosene Heater Association contends that these units
are very safe when used properly.
--- The Consumer Product Safety Commission has twice rejected petitions
asking that kerosene heaters be banned.
--- Consumer Reports: "CU thinks not. A kerosene heater's open flame
poses an obvious fire hazard. The gases it gives off as it burns pose a
less obvious ---- but no less serious --- problem. Storing kerosene
poses hazards of its own."
--- Fire officials remain concerned about the demanding management
practices that must be used to avoid making the heater dangerous.
--- No regulatory, social, or educational agency in Michigan currently
recommends using a portable, unvented heater in the home.
Precautions and Suggestions on Use
A portable kerosene heater can be used during waking hours to take the
chill off an area without starting up the central heating system. Its
temporary use can help remove dampness in a basement or vacation
cottage, and help provide working comfort in a garage, construction
site or storage area if adequate ventilation exists. A gas or unvented
portable kerosene heater has value for TEMPORARY use during a power
failure, especially in remote areas.
This information comes from Michigan State University Extension
bulletin E-1669, Some Considerations About Portable Kerosene Heaters.
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This information is for
educational purposes only. References to commercial products or trade
names does not imply endorsement by MSU Extension or bias against those
not mentioned. This information becomes public property upon
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Reprinting cannot be used to endorse or advertise a commercial product
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employer. Michigan State University Extension programs and materials
are open to all without regard to race, color, national origin, gender,
gender identity, religion, age, height, weight, disability, political
beliefs, sexual orientation, marital status, family status or veteran
status. Issued in furtherance of MSU Extension work, acts of May 8 and
June 30, 1914, in cooperation with the U.S. Department of Agriculture.
Thomas G. Coon, Director, MSU Extension, East Lansing,MI 48824. This
information is for educational purposes only. Reference to commercial
products or trade names does not imply endorsement by MSU Extension or
bias against those not mentioned.
information.was reviewed as
of June 2008. For more information about the contents please
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