FS 300Reprinted April 1994

Unvented Kerosene Space HeatersR. Topielec

An "unvented" kerosene heater is onethat lacks an attached and sealed exhaustsystem to remove fumes and unburnedgases (byproducts of kerosene combus-tion) from the space being heated. Ifunvented, these fumes and gases canbuild up and endanger the room'soccupants. A"vented" kerosene heater isone that has an attached and sealedexhaust system to remove these danger-ous fumes and gases to the outside of thespace being heated.

Oregon law prohibits the use ofportable unvented fuel burning heatersin residential buildingsand for goodreason.

One potential hazard of using anunvented kerosene heater is fire.Although many of the newer modelshave safety features (such as automaticcut-off switches to extinguish the flameif the unit is tipped over) and includerecommended clearances from combus-tible materials, accidents still happen.Most models are tested for operatingsafety by Underwriters Laboratories(UL), but there is no way to guaranteesafe operation.

If you must use an unvented keroseneheater, use it only in a non-residentialsetting such as a garage, workshop, ortool shed. Keep it in a place where noone can bump into it, and far enoughaway from anything combustible toeliminate a fire hazard. Select only aUL-approved heater and follow therecommended safety procedures tothe letter.

Another major concern is thepotentially harmful combustionbyproducts given off by unventedkerosene heaters. These byproducts arecarbon monoxide (CO), carbon dioxide(CO.,), nitrogen dioxide (NO2), andsulfur dioxide (SO2) gases that can beespecially harmful to infants, pregnant

4OREGON STATE UNIVERSITY

OffENSIONAr- SERVICE

women, the elderly, asthmatics, andpeople with cardiovascular diseases.

In 1982 and again in 1985, ConsumerReports tested what it considered to bethe best unvented kerosene heaters onthe market. They conducted the tests in achamber simulating the air-change rateof a moderately insulated houseaboutone complete air change per hour. Thetests showed that, even using the bestgrade kerosene available (1-K), theheaters gave off combustion byproductsexceeding the maximum acceptablelevels for all the above-mentionedpollutants.

The safest option is to never use anunvented kerosene heater in a residentialbuilding or living space. This is particu-larly true for highly weatherized ortightly built, energy-conserving homes.Some kerosene heater manufacturersrecommend that users keep doors toadjacent rooms open so the pollutantsaren't confined to one space, but thisonly distributes the pollutants intoanother living space.

Another recommendation is toprovide at least 4 square inches ofoutside ventilation area for each 1,000Btu per hour of heating capacity. Forexample, a 10,000 Btu-per-hour unitwould require 40 square inches ofventilation to the outside, or the spaceprovided by opening a 30-inch-widewindow l'/2 inches. However, thisresults in heat loss, and on calm daysthere may be insufficient air movementto remove all the combustion byproductsfrom the room. If convection from theheated air isn't enough to remove thepollutants, you may have to add a fan toinsure adequate air movement.

As economical and practical anunvented kerosene heater may seem, it'simportant to consider the conclusion ofthe 1985 Consumer Reports article:

97-Pt-rOvigetwij. V__ 00 --

/jie -Czr

/,/ 3 /

"We have yet to see a kerosene heaterthat burns cleanly enough to ease ourconcern about indoor air pollutionresulting from the use of these devices."

Follow these recommendations whenusing an unvented kerosene spaceheater:

Use only in a non-residential setting

Use only a UL-approved heater

Make sure the room or structure has asmoke detector

Provide adequate ventilation

Keep heater at least 3 feet fromcombustibles

Keep heater out of traffic areas

Keep children and pets away fromheater

Don't use flammable sprays orliquids near the heater

Use only 1-K grade kerosene

Allow heater to cool before refilling

Always refill heater outdoors

Check heater periodically for fuelleaks

Maintain heater according tomanufacturer's instructions

Store enough kerosene for only oneheating season

Store kerosene outside and awayfrom the house

Clearly label containers holdingkerosene

Richard R. Topielec, Extension agent,Oregon State University. Adapted fromKerosene Space Heaters, by Walter E.Matson, Extension agricultural engineeremeritus, Oregon State University.

Extension Service, Oregon State University, Corvallis, O.E. Smith, director. This publication was produced and distributed infurtherance of the Acts of Congress of May 8 and June 30, 1914. Extension work is a cooperative program of Oregon StateUniversity, the U.S. Department of Agriculture, and Oregon counties. Oregon State University Extension Service offerseducational programs, activities, and materialswithout regard to race, color, national origin, sex, age, or disabilityasrequired by Title VI of the Civil Rights Act of 1964, Title DC of the Education Amendments of 1972, and Section 504 of theRehabilitation Act of 1973. Oregon State University Extension Service is an Equal Opportunity Employer.