United States
 Environmental Protection
Air and Energy Engineering
Research Laboratory
Research Triangle Park NC 27711
 Research and Development
EPA/600/S7-90/004  May 1990
 Project Summary

 Characterization  of Population
 and  Usage of Unvented
 Kerosene Space  Heaters
 J. Barnes, P.Holland, and P. Mi hi master
  Indoor air quality is affected by a
number of synergistic  factors,
including combustion emissions from
unvented  appliances. Unvented
kerosene space heaters (UKSHs) can
be a significant  source  of such
emissions. To gather  baseline
information to help  assess  the
magnitude  and potential severity of
this problem, this study investigated
the market penetration of UKSH in the
residential sector. UKSH usage
patterns were also investigated.
  UKSH technology is fast evolving,
and   a   common  technical
nomenclature is difficult to define.
Many  individual  manufacturers
employ  their own terminology,  Most
units are  characterized  by  heat
transfer mechanism  (convective or
radiant), flame  type (blue or white),
and combustion mechanism (single
or dual  stage combustion and wick-
fed  or  wickless).  There are many
variations and combinations.
  Annual  sales  of  UKSHs  are
estimated  at 825,000 units. Leading
brands  include convective units
marketed by Toyotomi USA (Kero-
Sun) and Corona USA. Some units
contain  built-in catalytic filters for
odor control. Add-on catalytic filters
are  available  from  at least one
  It is  believed that 15-17 million
portable UKSHs have been sold in the
U. S. since  the early 1970s. However,
it is estimated  that in the 1986-1987
heating season,  there were  only
about 7 million units  in use. About
half of these units are in the South.
Depending on whether UKSHs are
used as  primary or  secondary
heating sources, they may be used
anywhere from 2 to 17 hours per day.
Eighty percent of UKSHs are used in
multi-family dwellings and mobile
homes. While the number of  UKSHs
is  fairly evenly  distributed across
income class, most kerosene
consumption is  among the lower
income groups (a small amount of
this kerosene  consumption may be
used in heating equipment other than
  Literature abstracts of publications
relating to UKSH  use and emissions
are in report Appendix B . Based on
the predominance of  UKSH use in
multi-family dwellings and mobile
homes, further study of these sectors
is  suggested  to more specifically
define usage characteristics.
  This Project Summary was
developed by EPA's Air and Energy
Engineering Research  Laboratory,
Research  Triangle  Park, NC,  to
announce key findings of the research
project that is  fully documented in a
separate report of the same title (see
Project Report ordering information at

,  This study had. a research objective
and an operational objective.  The
research  objective was to  describe
unvented kerosene space heater (UKSH)

technology, and to develop estimates  of
market  penetration  and  usage
characteristics. The operational objective
was  to  develop  recommendations for
specific  UKSHs to be laboratory tested
for emissions. These  recommendations
were to be  based on sales trends for
recent/current models, and for future
  With respect to the research objective
of this study,  the following  conclusions
can be drawn:
  •In the  1986-1987 heating season,
   there were an estimated  7 million
   UKSHs in use in the United States.

  • Depending upon whether used as a
   primary or secondary heating source,
   and  geographic location, it   is
   estimated  that UKSHs are operated
   from 2 to 17 hours per day.

  •Eighty   percent of  kerosene
   consumption  is  in  multi-family
   dwellings  and  mobile  homes,
   although not all of this consumption
   is in UKSHs.

  •Kerosene usage for space  heating  is
   generally concentrated in  the lower
   income groups.

  •Some units are marketed with built-in
   catalytic filters for odor  control,  and
   add-on catalytic devices are available
   from at least one  manufacturer.
   However, industry sources contend
   that future efforts  will  be focused on
   better combustion design, rather than
   post-combustion catalytic controls for
   reducing emissions.

  •The literature reviewed for  this study
   shows   that  UKSHs  can  be  a
   significant source of  indoor air
   pollutants,  including certain  organic
   compounds  which  may  be

  As representative  of  recent/current
best  selling models of UKSHs,  the
authors recommend the Kero-Sun Omni-
105,  an omnidirectional convective  unit
marketed by Toyotomi  USA, and  the
Corona  22DKC,  an  omnidirectional
convective  unit  marketed  by  Corona
USA. The  third  best-selling  unit  is
believed to  be the Robeson  03-2619-91,
a directional  radiant  unit marketed  by
Robeson Industries. These basic models
are expected to remain big  sellers over
the next several years.
  Representative  of models which may
see increased sales in the future are the
Toyostove Double Clean  100 and  the
Toyostove  Laser Clean  LR450,  both
marketed by Toyotomi USA. The former
represents an  advanced technology  for
UKSHs  known as dual  or. two-stage
combustion.  The  latter represents the
newer "wickless" technology.
 Based on  the above findings,  several
areas are identified which may  require
further research: use of UKSHs in mobile
homes and  multifamily  buildings,fuel
quality issues, synergistic  effects  of
unvented kerosene combustion and
combustion of other  appliances, and a
survey  of  kerosene households  to
examine usage patterns.

Use of UKSHs in  Mobile Homes
   According to initial  estimates based on
consumption  patterns,  about 33%  of
UKSHs  are used in mobile  homes.
Evidence ..indicates, that mobile homes.
particularly those constructed after 1974
when  new standards went into effect,
may be  substantially "tighter"  than
standard  single family dwellings. This is
based on  better quality  control  for
factory-built housing. Lower infiltration
rates  in  mobile homes  coupled with
unvented kerosene  combustion  could
lead to substantially higher levels  of
indoor air pollutants in mobile homes..A
complicating factor is that UKSHs  often
may be  the primary heating source in
mobile  homes (given their reduced
square footage)  and  thus could  be
operated  as much as 17  hours per day
on average. Further, mobile homes  are a
fast growing  segment  of the  housing
market, and  many have  relatively high
proportions  of  infants and  the  elderly
susceptible  subpopulations. The authors
recommend a research effort to measure
infiltration rates in typical  mobile homes
(both  pre- and post-1974) and  better
define the saturation and usage patterns
of UKSHs in mobile homes. Growth rates
and occupancy patterns should also  be
examined;	=	'—	

Use  of UKSHs  in   Multifamily
   Initial estimates indicate that fully 47%
of UKSHs may be used  in  multifamily
dwellings. Most research to date  on
emissions has concentrated on  single
family dwellings, yet the standard single
family dwelling sector only accounts  for
an estimated 20% of households  using
UKSHs. Further,  preliminary evidence
exists which  indicates a wide degree of
variability in infiltration rates in multifamily
buildings.  The  major  reasons are
exposure and stack effects. While single
family buildings  typically  have four
exterior walls,  apartments in  multifamily
buildings  may  have  only  one  exterior
wall. Limited measurements indicate that
an apartment ori the leeward  side of a
multifamily building may have  infiltration
rates only slightly above zero air changes
per hour,(ACHs),although this  may only
be a transient situation.  Use of an UKSH
in such an  apartment could periodically
lead to very  high  levels  of pollutants.
Health effects are complicated by the fact
that many  apartment dwellers  may
include susceptible subpopulations such
as the  elderly and  infants. The authors
recommend an effort to  better define the
saturation,  usage  patterns,  and
occupancy  characteristics  of UKSH
usage  in  multifamily  dwellings.  This
should  be coupled  with  an  emissions
characterization which includes testing  in
multifamily building environments. ...

Fuel Quality Issues
   K-1 is the recommended kerosene fuel
for  most UKSHs. K-2  is a  somewhat
"dirtier"  fuel which  is  also  widely
available. Since K-2 is  usually  slightly
cheaper than  K-1, some individuals may
be tempted to use K-2  in their  UKSHs.
This could lead to higher emission rates
for  certain  pollutants.  Note  that" this
problem is not limited to willful misuse by
the  consumer.  There have been
documented  cases  of  K-2 kerosene's
being labeled and sold as K-1  kerosene
by dealers. The magnitude and  severity
of this  problem is unknown. The authors
suggest a limited effort be undertaken  to
examine this  issue.  This  would include
random spot sampling  of  kerosene
offered for sale to determine fuel quality
coupled with characterization  of the
emissions of UKSHs when combusting  K-
2 kerosene.

Synergistic Effects of Unvented
Kerosene  Combustion  and
Go m b u s t i o n	o f     Other
   UKSHs  may  be used  in conjunction
with  unvented gas appliances,  such as
gas  cooking  stoves. While  numerous
experiments  have been conducted for
criteria pollutants,  only limited  work has
been  done  to explicitly  measure the
interactive  effects of gas  and  kerosene
combustion  for non-criteria  pollutants
(e.g., PAHs). It is suggested that a limited
effort be undertaken to  characterize the
interactive  effects. If  this results  in
concerns, further analysis could  attempt
to estimate the population of households
where both  unvented kerosene  and gas
appliances are in use.

Survey    of    Kerosene
Households to Examine  Usage
   This  study has estimated  usage
patterns  for  UKSHs  based  on total
kerosene consumption estimates.  To
better understand actual usage  and
behavior  patterns, it  is  important to
survey users to gauge  variables such as
number of hours  of operation per day,
age and  health of building occupants,
number of units in use, location of units,
and whether or not supplemental heating
is  used. To accomplish this, a limited
survey of kerosene heater users would
be necessary. The suggested  approach
would be to "piggy back" on  existing
residential energy surveys  such as those
conducted  by  the  U.S.  Energy
Information Administration, where  a
secondary survey would be administered
to  respondents  having  identified
themselves as  UKSH users..

  J.Barnes, P.Holland, and P.Mihlmester are with Applied Management Sciences,
      Inc., Oak Ridge, TN 37830..
  James B. White is the EPA Project Officer (see below)..
  The complete report, entitled "Characterization  of Population and Usage  of
     Unvented Kerosene Space Heaters," (Order No. PB 90 155 573/AS;  Cost:
     $17.00 ,  subject to change) will be available only from:
           National Technical Information Service
           5285 Port Royal Road
           Springfield, VA 22161
           Telephone: 703-487-4650
  The EPA Project Officer can be contacted at:
           Air and Energy Engineering Research Laboratory
           U.S. Environmental Protection Agency
           Research Triangle Park, NC  27711
United States
Environmental Protection
Center for Environmental Research
Cincinnati OH 45268
Official Business
Penalty for Private Use S300