U.S. Department of Homeland Security • U.S. Fire Administration

National Fire Data Center • Emmitsburg, Maryland 21727

www.usfa.dhs.gov/statistics/reports/index.shtm

Topical Fire Report Series Volume 10, Issue 2 / January 2010

Heating Fires in Residential Buildings 

These topical reports are designed to 

explore facets of the U.S. fire problem as 

depicted through data collected in the U.S. 

Fire Administration’s (USFA’s) National Fire 

Incident Reporting System (NFIRS). Each 

topical report briefly addresses the nature 

of the specific fire or fire-related topic, highlights important findings from the data, and 

may suggest other resources to consider for 

further information. Also included are recent 

examples of fire incidents that demonstrate 

some of the issues addressed in the report or 

that put the report topic in context.

Findings

■ An estimated 54,500 heating fires occur each year in the United States.

■ Heating is the second leading cause of all residential building fires following cooking.

■ Residential building heating fires peak in January and February; this peak accounts for 34 

percent of fires.

■ Confined heating fires, those fires confined to chimneys, fuels, fuel boxes, or boilers, account 

for 87 percent of residential building heating fires.

■ Thirty-one percent of the nonconfined residential building heating fires occur because the 

heat source is too close to combustibles.

■ Residential building heating fires peak in the early evening hours between 5 p.m. and 9 p.m. 

with the highest peak between 6 p.m. and 8 p.m. This 4-hour period accounts for 30 percent 

of all residential building heating fires.

■ The percent of residential building heating fires declines to the lowest point during the 

summer months from June to August. Heating fires during these months tend to be confined 

fuel burner/boiler malfunction fires (64 percent) or involve water heaters (10 percent).

From 2005 to 2007, an estimated average of 54,500 

heating fires in residential buildings occurred in the 

United States each year. Heating fires account for 14 percent of residential building fires responded to by fire 

departments across the Nation.1,2,3 These fires resulted in 

an average of 190 deaths, 625 injuries, and $286 million 

in property loss. The term heating fires applies to those fires 

that are caused by central heating units, fixed or portable 

local heating units, fireplaces, heating stoves, chimneys, and 

water heaters.4

 This topical report addresses the characteristics of residential building heating fires reported to the 

National Fire Incident Reporting System (NFIRS) between 

2005 and 2007.

For the purpose of this report, the term “residential heating fires” is synonymous with “residential building heating 

fires” as residential heating fires commonly mean those fires 

caused by heating that occur in buildings. “Residential heating fires” is used throughout the body of this report; the 

findings, tables, charts, headings, and footnotes reflect the 

full category “residential building heating fires.”

Between 2005 and 2007, heating fires were the second 

leading cause of all residential building fires. Previously, 

especially during the late 1970s and early 1980s, heating 

fires were by far the leading cause of residential building 

fires. Stimulated in part by an energy shortage, this surge 

in heating fires was the result of the sudden increased use 

of alternative heating, particularly wood heating stoves and 

space heaters. Since then, the overall numbers of heating fires have substantially decreased. In 1983, there were 

200,000 heating fires, but by 2007, that number had fallen 

to approximately 54,000.5

 

Type of Fire

Building fires consist of two major categories of incidents: 

fires that are confined to specific types of equipment or 

objects (confined fires) and those that are not (nonconfined 

fires). Confined building fires are small fire incidents that 

are limited in scope, confined to noncombustible containers, rarely result in serious injury or large content losses, 

and are expected to have no significant accompanying 

property losses due to flame damage.6

 Eighty-seven percent 

of residential heating fires are confined fires as shown in 

Table 1. By comparison, just under half (47 percent) of all 

residential fires are confined fires.

continued on next page
TFRS Volume 10, Issue 2/Heating Fires in Residential Buildings Page 2

Table 1. Residential Building Heating Fires by Type of Incident (2005–2007) 

Incident Type Percent

Nonconfined fires 13.0

Confined fires 87.0

Chimney or flue fire, confined to chimney or flue 53.0

Fuel burner/boiler malfunction, fire confined 34.0

Total 100.0

Source: NFIRS 5.0.

Loss Measures

Table 2 presents losses, averaged over this 3-year period, for residential building fires and heating fires reported to NFIRS.7

Table 2. Loss Measures for Residential Building Heating Fires (3-year average, 2005–2007)

Measure Residential Building 

Fires

Residential Building

Heating Fires

Confined Residential 

Building Heating Fires

Nonconfined Residential 

Building Heating Fires

Average Loss: N/A N/A N/A N/A

Fatalities/1,000 Fires 5.4 1.9 0.0 14.4

Injuries/1,000 Fires 28.1 9.3 2.7 53.8

Dollar Loss/Fire $14,560 $3,540 $240 $25,490

Source: NFIRS 5.0. 

Notes: 1) One death in a confined fire was reported to NFIRS during 2005–2007; the resulting loss of 0.0 fatalities per 1,000 fires reflects only data reported to NFIRS.

2) Average loss for fatalities and injuries is computed per 1,000 fires; average dollar loss is computed per fire and is rounded to the nearest $10.

When Residential Building Heating Fires Occur

As shown in Figure 1, residential building heating fires 

occur mainly in the evening hours, 5 p.m. to 9 p.m., peaking from 6 p.m. to 8 p.m. They decline throughout the 

night and early morning and reach their lowest point during the morning hours (3 a.m. to 5 a.m.). The 4-hour evening period from 5 p.m. to 9 p.m. accounts for 30 percent 

of residential building heating fires and the 2-hour morning 

period between 3 a.m. and 5 a.m. accounts for 3 percent.8

The small, confined fire incidents dominate the alarm 

profile and produce the pronounced peaks and valleys; the 

larger, nonconfined fires, experience an early morning low 

and an evening peak as well, but less pronounced. In general, they occur more regularly throughout the day.

Figure 1. Residential Building Heating Fires by Time of Alarm (2005—2007)

Source: NFIRS 5.0. 
TFRS Volume 10, Issue 2/Heating Fires in Residential Buildings Page 3

As to be expected, residential heating fires are most prevalent during the winter months from December through 

February when the use of central heating systems, portable 

heaters, and fireplaces is most common (Figure 2). The 

incidence of heating fires peaks in January and February 

at 17 percent each. From March to August, fires decline 

from 13 percent to 2 percent. The percent of fires declines 

to the lowest point during the summer months from June 

to August, corresponding to reduced heating activities 

in residential buildings. Both confined and nonconfined 

residential heating fires follow this overall pattern of winter 

peaks and summer lows. Residential heating fires during 

the summer months tend to be confined fuel burner/boiler 

malfunction fires (64 percent) or involve water heaters 

(10 percent).

Figure 2. Residential Building Heating Fires by Month (2005–2007)

Source: NFIRS 5.0. 

Fire Spread in Residential Building 

Heating Fires

Ninety percent of residential heating fires are confined to 

the object of origin (Figure 3). These fires are primarily 

coded as confined fires in NFIRS—96 percent of residential heating fires confined to the object of origin are coded 

as confined fires.9

 Few fires, 5 percent, extend beyond the 

room of origin. 

Confined Fires

NFIRS allows abbreviated reporting for confined fires and 

many reporting details of these fires are not required nor 

reported. Confined residential heating fires account for the 

majority of residential heating fire incidents and dominate 

the time of alarm profile. The numbers of confined fires 

are greatest during the hours of 5 p.m. to 9 p.m. when 

they account for 91 percent of fires that occur during this 

period. Confined residential heating fires peak in January 

and February, decline through May, and are lowest during 

the months of June through August. 
TFRS Volume 10, Issue 2/Heating Fires in Residential Buildings Page 4

Figure 3. Extent of Fire Spread in Residential Building Heating Fires (2005–2007)

Source: NFIRS 5.0.

Nonconfined Fires

The next sections of this topical report will address nonconfined residential heating fires, where detailed fire data are 

available.

Where Nonconfined Residential Building 

Heating Fires Start

One- and two-family residences are disproportionately 

represented in residential heating fires. Heating fires in 

one- and two-family residences account for 81 percent 

of residential heating fires—yet one- and two-family 

residences represent only 66 percent of residential fires. 

Multifamily dwellings account for an additional 15 percent 

of these heating fires. Multifamily dwellings (apartments, 

condominiums, and the like) often have professionally 

maintained heating systems which may account for these 

differences in fire incidence.

Five areas in the home—heating rooms/areas or water 

heater areas (16 percent); cooking areas and kitchens (11 

percent); common rooms or lounge areas (10 percent); 

bedrooms (9 percent), and walls or concealed wall spaces 

(7 percent)—account for over half of nonconfined residential heating fires (Table 3).

Table 3. Leading Areas of Fire Origin in Nonconfined Residential Building Heating Fires 

(2005–2007)

Area of Origin Percent (Unknowns Apportioned)

Heating room or area, water heater area 16.1

Cooking area, kitchen 10.7

Common room, den, family room, living room, lounge 10.4

Bedrooms 8.8

Wall assembly, concealed wall space 6.7

Source: NFIRS 5.0.
TFRS Volume 10, Issue 2/Heating Fires in Residential Buildings Page 5

Items First Ignited in Nonconfined 

Residential Building Heating Fires

Forty percent of the items first ignited in nonconfined residential heating fires fall under the “structural component or 

finish” category (Figure 4). This category includes structural members or framing, exterior trim and finishes, interior wall coverings, insulation within the walls, partitions, 

and floor/ceiling surfaces. The second leading category 

is “general materials,” a catch-all category that includes 

items such as electrical wire insulation, trash/rubbish, and 

residues (such as chimney residue). The general materials 

category accounts for 17 percent of nonconfined residential 

heating fires. At 12 percent, “furniture” is the third leading 

category of items first ignited. 

Structural members or framing (18 percent) and electrical 

wire and cable insulation (11 percent) are the specific items 

most often first ignited in nonconfined residential 

heating fires.

Figure 4. Item First Ignited in Nonconfined Residential Building Heating Fires 

by Major Category (2005–2007)

Source: NFIRS 5.0.

Fire Spread in Nonconfined Residential 

Building Heating Fires

The majority of nonconfined fires, 64 percent, are limited 

to the object or room of fire origin (Figure 5). The fire 

spread profile for nonconfined residential heating fires is 

similar to the fire spread profile for all nonconfined residential fires with slightly more nonconfined heating fires being 

confined to the room or object of origin. 
TFRS Volume 10, Issue 2/Heating Fires in Residential Buildings Page 6

Figure 5. Extent of Fire Spread in Nonconfined Residential Building Heating Fires 

(2005–2007)

Source: NFIRS 5.0.

Factors Contributing to Ignition

Table 4 shows the categories of factors contributing to ignition for nonconfined residential heating fires. The “misuse 

of material or product” is the leading category contributing (39 percent) to the ignition of nonconfined residential 

heating fires. “Mechanical failure or malfunction” is the 

second leading category in 23 percent of residential heating fires and “operational deficiency” is the third leading 

category in 18 percent of the fires. These 3 categories play a 

role in 79 percent of nonconfined residential heating fires. 

Heat source too close to combustibles (31 percent) is, by 

far, the leading specific factor contributing to ignition. Heat 

source too close to combustibles is more than twice the second leading factor contributing to ignition, miscellaneous 

mechanical failure/malfunction (13 percent).

Table 4. Factors Contributing to Ignition for Nonconfined Residential Building Heating Fires 

by Major Category (Where Factor Contributing Specified, 2005–2007)

Factor Contributing to Ignition Category Percent of Nonconfined Residential Building Heating Fires 

(Unknowns Apportioned)

Misuse of material or product 38.7

Mechanical failure, malfunction 22.7

Operational deficiency 17.6

Electrical failure, malfunction 17.2

Design, manufacture, installation deficiency 10.5

Other factors contributing to ignition 3.4

Natural condition 0.9

Fire spread or control 0.8

Source: NFIRS 5.0. 

Notes: 1) Includes only incidents where factors that contributed to the ignition of the fire were specified. 

2) Multiple factors contributing to fire ignition may be noted for each incident; total will exceed 100 percent. 
TFRS Volume 10, Issue 2/Heating Fires in Residential Buildings Page 7

Suppression/Alerting Systems in 

Residential Building Heating Fires

Smoke alarm data are available for both confined and nonconfined fires although for confined fires, the data are very 

limited in scope.

Smoke alarms were present in 54 percent of nonconfined 

residential heating fires (Table 5). Smoke alarms are known 

to have operated in 30 percent of nonconfined heating fires. 

Smoke alarms were not present in 23 percent of the nonconfined residential heating fires. Firefighters were unable 

to determine if a smoke alarm was present in another 23 

percent of these nonconfined fires. Of the nonconfined 

residential heating fires where a smoke alarm was present, 

the alarms failed to operate in 18 percent of the incidents. 

Smoke alarms operated and alerted occupants in 20 percent of confined fires (Table 6). Occupants were not alerted 

by the smoke alarm in 25 percent of confined residential 

heating fires.10 Smoke alarm effectiveness was unknown in 

55 percent of confined residential heating fires. Note that 

the data presented in Table 5 and Table 6 are the raw counts 

from the NFIRS data set and not scaled to national estimates 

of smoke alarms in residential heating fires.

Table 5. NFIRS Smoke Alarm Data for Nonconfined Residential Building Heating Fires 

(NFIRS, 2005–2007)

Presence of 

Smoke Alarms Smoke Alarm Operational Status Smoke Alarm Effectiveness Count Percent

Present

Fire too small to activate smoke alarm 842 8.0

Smoke alarm operated

Smoke alarm alerted occupants, occupants responded 2,336 22.2

Smoke alarm alerted occupants, occupants failed to respond 109 1.0

No occupants 353 3.3

Smoke alarm failed to alert occupants 86 0.8

Undetermined 240 2.3

Smoke alarm failed to operate 1,005 9.5

Undetermined 733 7.0

None present 2,371 22.5

Undetermined 2,468 23.4

Total Incidents 10,543 100.0

Source: NFIRS 5.0.

Notes: The data presented in this table are raw data counts from the NFIRS data set. They do not represent national estimates of smoke alarms in nonconfined residential building heating fires. They are presented 

for informational purposes. Total may not add to 100 percent due to rounding.

Table 6. NFIRS Smoke Alarm Data for Confined Residential Building Heating Fires 

(NFIRS, 2005–2007)

Smoke Alarm Effectiveness Count Percent

Smoke alarm alerted occupants 14,356 20.4

Smoke alarm did not alert occupants 17,432 24.8

Unknown 38,501 54.8

Null/Blank 1 0.0

Total Incidents 70,290 100.0

Source: NFIRS 5.0.

Notes: The data presented in this table are raw data counts from the NFIRS data set. They do not represent national estimates of smoke alarms in confined residential building heating fires. They are presented for 

informational purposes. Total may not add to 100 percent due to rounding.
TFRS Volume 10, Issue 2/Heating Fires in Residential Buildings Page 8

Automatic Extinguishing System (AES) data are only available for nonconfined fires. Full or partial AESs were present 

in only 2 percent of nonconfined residential heating fires 

(Table 7). The lack of AES is not unexpected as only 3 percent of all nonconfined residential building fires have AES 

present.

Table 7. NFIRS Automatic Extinguishing System Data for Nonconfined Residential Building 

Heating Fires (2005–2007)

AES Presence Count Percent

AES present 256 2.4

Partial system present 5 0.0

AES not present 9,908 94.0

Undetermined 374 3.5

Total Incidents 10,543 100.0

Source: NFIRS 5.0.

Notes: The data presented in this table are raw data counts from the NFIRS data set. They do not represent national estimates of AESs in nonconfined residential building heating fires. They are presented for informational purposes. Totals may not add to 100 percent due to rounding.

Examples

The following are some recent examples of residential heating fires. These fires were reported by the media.

•	 June 2009: Hillsboro, OR, fire officials reported that a 

fire was caused in a home when the homeowner was 

replacing his water heater. The homeowner was using 

a propane torch to connect the water pipes when the 

flames erupted. The damage was contained to the crawl 

spaces of the home.11

•	 June 2009: A furnace that was overdue for repairs and 

that may have been modified is likely to blame for a fire 

in the Newman Building in Durango, CO, which displaced several tenants. The fire caused severe structural 

damage. Damaged insulation around electrical wiring 

and misplacement of an air filter in the furnace were 

under investigation as causes of the furnace fire.12

•	 October 2009: Firefighters responded to a multifamily building fire started by a boiler in the basement. 

Residents were evacuated and the fire was extinguished. 

This fire marked one of several boiler fires that the 

Providence, RI, firefighters had responded to over the 

past few weeks. The fire chief recommended that people 

call a heating professional each year to check their heating systems.13

•	 October 2009: Two people were displaced from their 

home in Lancaster, OH, when a baseboard heating fire 

destroyed their house. No one was injured and firefighters were able to control the blaze within minutes of 

arriving on the scene.14

Conclusion

Safer heating equipment and public awareness of heating 

fire prevention have substantially decreased the incidence of 

residential heating fires. Chimney maintenance is now more 

often the norm rather than the exception. Although the 

numbers of these fires have decreased, residential building 

heating fires still affect neighborhoods and communities, 

and therefore, continue to receive attention within local 

fire departments and State agencies. This attention is largely 

because residential building heating fires account for and 

cause injuries and deaths as well as property damage. Many 

of these fires can be prevented through proper maintenance 

and proper use of heating equipment. 

Despite the decrease in residential building heating fires, 

they remain worrisome. The ebb and flow of energy pricing and availability affects the choices people make to heat 

their homes. As conventional energy sources—oil, electricity, natural gas, etc. — rise and fall in price and availability, 

alternative heating becomes more attractive, and with it, the 

potential for the reemergence of residential heating fires.

NFIRS Data Specifications for Residential 

Building Heating Fires

Data for this report were extracted from the NFIRS annual 

Public Data Release files for 2005, 2006, and 2007. Only 

version 5.0 data were extracted.

Residential building heating fires were defined as:

•	 Incident Types 111, 112, 114, 116, 120 to 123:15

continued on next page
TFRS Volume 10, Issue 2/Heating Fires in Residential Buildings Page 9

Incident 

Type Description

111 Building fire

112 Fires in structure other than in a building

114 Chimney or flue fire, confined to chimney or flue

116 Fuel burner/boiler malfunction, fire confined

120 Fire in mobile property used as a fixed structure, other

121 Fire in mobile home used as fixed residence

122 Fire in motor home, camper, recreational vehicle

123 Fire in portable building, fixed location

Note that Incident Types 114 and 116 do not specify if 

the structure is a building.

Incident Type 112 is included as previous analyses 

have shown that Incident Types 111 and 112 are used 

interchangeably.

•	 Structure type:

– 1 - Enclosed building

– 2 - Fixed portable or mobile structure

– Structure type not specified (null entry)

•	 Aid types 3 (mutual aid given) and 4 (automatic aid 

given) were excluded to avoid double counting of 

incidents.

•	 Property use 400 to 464:

Property 

Use Description

400 Residential, other

419 One- and two-family dwelling

429 Multifamily dwelling

439 Boarding/Rooming house, residential hotels

449 Hotel/Motel, commercial

459 Residential board and care

460 Dormitory-type residence, other

462 Sorority house, fraternity house

464 Barracks, dormitory

•	 The USFA cause hierarchy was used to determine residential building heating fire incidents:16

•	 Heating fire incidents involving heating stoves and food 

were believed to be cooking fires. As a result, fires with 

equipment involved in ignition code 124 (stove, heating) and item first ignited code 76 (cooking materials; 

includes edible materials for man or animal; excludes 

cooking utensils) were removed from the query.

To request additional information or to comment on this 

report, visit http://www.usfa.dhs.gov/applications/feedback/index.jsp

Notes:

1 National estimates are based on 2005 to 2007 native version 5.0 data from the National Fire Incident Reporting System 

(NFIRS) and residential structure fire loss estimates from the National Fire Protection Association’s (NFPA) annual surveys 

of fire loss. Fires are rounded to the nearest 100, deaths to the nearest 5, injuries to the nearest 25, and loss to the nearest 

$million.

2 In NFIRS, version 5.0, a structure is a constructed item of which a building is one type. In previous versions of NFIRS, the 

term “residential structure” commonly referred to buildings where people live. To coincide with this concept, the definition 

of a residential structure fire for NFIRS 5.0 has, therefore, changed to include only those fires where the NFIRS 5.0 structure type is 1 or 2 (enclosed building and fixed portable or mobile structure) with a residential property use. Such fires are 

referred to as “residential buildings” to distinguish these buildings from other structures on residential properties that may 

include fences, sheds, and other uninhabitable structures. In addition, incidents that have a residential property use, but do 

not have a structure type specified are presumed to be buildings.

3 Residential buildings include, but are not limited to, one- or two-family dwellings, multifamily dwellings, boarding houses 

or residential hotels, commercial hotels, college dormitories, and sorority/fraternity houses.

4 For purposes of this analysis, residential building heating fires are defined as those residential buildings (defined above) for 

which the cause of the fire was determined to be heating. However, for the confined fire portion of residential building fires, 

only those with incident types 114 and 116 were included; all other confined fire types were excluded.

5 Fire in the United States 1983–1990, Eighth Edition, U.S. Fire Administration, Federal Emergency Management Agency, 

October 1993. 

continued on next page
TFRS Volume 10, Issue 2/Heating Fires in Residential Buildings Page 10

6 NFIRS distinguishes between “content” and “property” loss. Content loss includes loss to the contents of a structure due to 

damage by fire, smoke, water, and overhaul. Property loss includes losses to the structure itself or to the property itself. Total 

loss is the sum of the content loss and the property loss. For confined fires, the expectation is that the fire did not spread 

beyond the container (or rubbish for incident type 118) and hence, there was no property damage (damage to the structure 

itself) from the flames. There could be, however, property damage as a result of smoke, water, and overhaul.

7 The average fire death and fire injury loss rates computed from the national estimates above will not agree with average 

fire death and fire injury loss rates computed from NFIRS data alone. The fire death rate computed from national estimates 

would be (1,000*(190/54,500)) = 3.5 deaths per 1,000 residential building heating fires and the fire injury rate would be 

(1,000*(625/54,500)) =11.5 injuries per 1,000 residential building heating fires. 

8 For the purposes of this report, the time of the fire alarm is used as an approximation for the general time the fire started. 

However, in NFIRS, it is the time the fire was reported to the fire department.

9 In NFIRS, confined fires are defined by Incident Type codes 113 to 118.

10 In confined fires, the entry “smoke alarm did not alert occupants” can mean: no smoke alarm was present, the smoke 

alarm was present but did not operate, or the smoke alarm was present and operated but the occupant was already aware of 

the fire.

11 “Soldering Torch Sparks Residential Fire in Hillsboro,” Salem-News.com, June 24, 2009. 

http://www.salem-news.com/articles/june242009/hillsboro_fire_6-24-09.php (accessed July 7, 2009).

12 Garrett Andrews, “Furnace likely cause of April fire,” durangoherald.com, June 27, 2009. http://durangoherald.com/sections/News/2009/06/27/Furnace_likely_cause_of_April_fire/ (accessed July 10, 2009).

13 Kate Bramson, “Weather keys rash of boiler fire calls,” www.projo.com, October 17, 2009. 

http://www.projo.com/news/content/BOILER_FIRES_10-17-09_CAG499L_v6.353f3d9.html (accessed October 28, 

2009). 

14 Morgan Day, “Residents say baseboard heating caused fire in home,” www.lancastereaglegazette.com, October 27, 2009. 

http://www.lancastereaglegazette.com/article/20091027/NEWS01/910270305.

15 Heating is defined by the equipment used to heat a residential building. Incident Types 113, 115, 117, and 118 were 

excluded because by definition these Incident Types were not heating fires.

16 The USFA cause hierarchy is designed for structure fires. Buildings are a subset of structures. The cause hierarchy can be 

found at: http://www.usfa.dhs.gov/fireservice/nfirs/tools/fire_cause_category_matrix.shtm.