Million U.S. Housing Units

Total......................................................................... 111.1 10.9 26.1 27.3 24.0 22.8

Do Not Have Cooling Equipment........................... 17.8 3.2 4.7 3.6 5.5 0.9

Have Cooling Equipment........................................ 93.3 7.7 21.4 23.7 18.5 21.9

Use Cooling Equipment......................................... 91.4 7.6 21.0 23.4 17.9 21.7

Have Equipment But Do Not Use it........................ 1.9 Q 0.4 0.4 0.6 0.3

Type of Air-Conditioning Equipment2, 3

Central System..................................................... 65.9 4.8 12.3 15.1 14.9 18.7

Without a Heat Pump......................................... 53.5 4.7 11.5 11.6 12.3 13.6

With a Heat Pump.............................................. 12.3 Q 0.9 3.5 2.7 5.2

Window/Wall Units.............................................. 28.9 3.1 9.3 8.8 4.0 3.7

1 Unit................................................................. 14.5 2.1 5.0 3.6 2.4 1.4

2 Units................................................................ 9.1 0.7 2.9 3.3 1.0 1.2

3 or More Units.................................................. 5.4 0.3 1.5 1.9 0.6 1.1

Central Air-Conditioning Usage

Air-Conditioned Floorspace (Square Feet)

None.................................................................. 45.2 6.2 13.7 12.2 9.0 4.1

1 to 499.............................................................. 3.9 Q 0.7 0.6 1.2 1.2

500 to 999.......................................................... 15.0 0.7 2.6 2.8 4.3 4.7

1,000 to 1,499.................................................... 15.6 0.8 2.7 3.3 4.0 4.8

1,500 to 1,999.................................................... 11.1 0.7 2.2 2.4 2.1 3.8

2,000 to 2,499.................................................... 7.0 0.8 1.2 1.9 1.3 1.8

2,500 to 2,999.................................................... 5.2 0.5 1.1 1.4 1.0 1.2

3,000 or 3,499.................................................... 2.7 0.3 0.7 0.9 0.4 0.4

3,500 to 3,999.................................................... 1.8 0.3 0.4 0.6 0.3 Q

4,000 or More..................................................... 3.5 0.4 0.9 1.1 0.5 0.6

Number of Rooms Cooled by Central

Air-Conditioning in Summer 2005

None.................................................................. 1.4 Q 0.3 Q 0.6 0.2

1......................................................................... 0.7 N QQQQ

2......................................................................... 2.1 Q 0.5 0.4 0.5 0.5

3......................................................................... 7.5 0.4 1.4 1.3 2.0 2.4

4......................................................................... 7.9 0.4 1.2 1.8 1.9 2.6

5 or More............................................................ 46.3 3.7 8.9 11.2 9.9 12.7

Proportion of Rooms Air-Conditioned

None.................................................................. 1.4 Q 0.3 Q 0.6 0.2

Some, But Not all of the Rooms......................... 8.4 0.7 1.8 1.6 2.4 1.9

All of the Rooms................................................. 56.1 4.0 10.2 13.2 12.0 16.6

Frequency of Central Air-Conditioner Use

Never................................................................. 1.4 Q 0.3 Q 0.6 0.2

Only a Few Times When Needed....................... 11.4 1.7 3.1 2.3 3.5 0.9

Quite a Bit.......................................................... 12.6 1.6 3.3 2.8 2.9 2.0

All Summer........................................................ 40.5 1.4 5.6 9.8 8.0 15.6

Table HC9.7 Air-Conditioning Usage Indicators by Climate Zone, 2005

Air-Conditioning Usage Indicators

2,000 CDD 

or More

and Less 

than 4,000 

HDD

Less than 2,000 CDD and --

Greater than 

7,000 HDD

5,500 to 

7,000 HDD

4,000 to 

5,499 HDD

Less than 

4,000 HDD

Housing 

Units 

(millions)

Climate Zone1

Energy Information Administration

2005 Residential Energy Consumption Survey: Preliminary Housing Characteristics Tables
 Million U.S. Housing Units

Table HC9.7 Air-Conditioning Usage Indicators by Climate Zone, 2005

Air-Conditioning Usage Indicators

2,000 CDD 

or More

and Less 

than 4,000 

HDD

Less than 2,000 CDD and --

Greater than 

7,000 HDD

5,500 to 

7,000 HDD

4,000 to 

5,499 HDD

Less than 

4,000 HDD

Housing 

Units 

(millions)

Climate Zone1

At Home Behavior

Home Used for Business

Yes................................................................. 6.4 0.7 1.0 1.5 1.4 1.8

No.................................................................. 59.5 4.0 11.3 13.6 13.5 16.9

Someone Home All Day

Yes................................................................. 32.7 1.8 6.4 7.2 7.7 9.6

No.................................................................. 33.1 2.9 5.9 7.9 7.2 9.2

Housing Unit Characteristics Affecting Usage

in Centrally Air-Conditioned Housing Units

Large Tree(s) that Shade the Home

Yes.................................................................... 31.6 2.6 5.8 7.9 7.1 8.2

No...................................................................... 34.3 2.1 6.6 7.1 7.9 10.6

Adequacy of Insulation

Well Insulated.................................................... 29.5 2.6 5.7 7.2 6.7 7.4

Adequately Insulated.......................................... 27.9 1.8 5.3 5.8 6.5 8.6

Poorly Insulated................................................. 7.3 0.4 1.2 2.0 1.5 2.3

No Insulation...................................................... 0.3 N QQQQ

Don't Know......................................................... 0.9 Q Q Q Q 0.3

Home Is Too Drafty During the Winter

Never................................................................. 42.6 3.1 7.3 9.0 9.6 13.6

Some of the Time............................................... 16.3 1.2 3.5 4.1 3.9 3.4

Most of the Time................................................ 2.5 Q 0.6 0.6 0.6 0.6

All of the Time.................................................... 2.2 Q 0.5 0.8 0.5 0.4

Don't Know......................................................... 2.2 Q 0.4 0.5 0.3 0.8

Unusually High Ceilings

Yes.................................................................... 20.3 1.5 3.7 4.0 4.9 6.2

No...................................................................... 41.9 3.1 8.3 10.4 9.0 11.1

Not Asked (Mobile Homes)................................ 3.7 Q 0.4 0.7 1.0 1.4

Cathedral Ceilings

(In Housing Units with High Ceilings)

Yes............................................................. 13.5 1.2 2.5 2.5 3.2 4.2

No............................................................... 6.7 0.4 1.2 1.5 1.7 2.0

Type of Glass in Windows

Single-pane Glass.............................................. 27.4 1.3 3.1 4.4 7.1 11.5

Double-pane Glass

Without Low-e Coating................................... 31.5 2.4 7.4 8.9 6.8 6.0

With Low-e Coating........................................ 5.8 1.0 1.6 1.4 1.0 1.0

Triple-pane Glass

Without Low-e Coating................................... 0.8 QQQQQ

With Low-e Coating........................................ Q Q Q N Q Q

Proportion of Windows Replaced

All....................................................................... 11.5 0.7 3.3 3.4 2.3 1.7

Some................................................................. 11.1 1.2 2.4 2.7 2.2 2.6

None.................................................................. 40.9 2.8 6.3 8.3 10.1 13.5

Energy Information Administration

2005 Residential Energy Consumption Survey: Preliminary Housing Characteristics Tables
 Million U.S. Housing Units

Table HC9.7 Air-Conditioning Usage Indicators by Climate Zone, 2005

Air-Conditioning Usage Indicators

2,000 CDD 

or More

and Less 

than 4,000 

HDD

Less than 2,000 CDD and --

Greater than 

7,000 HDD

5,500 to 

7,000 HDD

4,000 to 

5,499 HDD

Less than 

4,000 HDD

Housing 

Units 

(millions)

Climate Zone1

Thermostats

Thermostat Available During Summer

Yes.................................................................... 63.9 4.7 11.8 14.6 14.6 18.3

No...................................................................... 1.9 Q 0.6 0.5 0.4 0.5

Do Not Use Central Air-Conditioning.................. 45.2 6.2 13.7 12.2 9.0 4.1

Use a Programmable Thermostat

Yes............................................................. 25.0 2.2 5.5 4.9 6.6 5.8

No............................................................... 38.9 2.5 6.3 9.7 8.0 12.4

Use of Programmable Thermostats

Adjusts Temperature During Day

Yes................................................................. 15.1 1.3 3.4 2.9 4.0 3.6

No.................................................................. 9.9 0.9 2.2 2.0 2.6 2.2

Adjusts Temperature at Night

Yes................................................................. 15.4 1.4 3.4 3.0 4.0 3.7

No.................................................................. 9.6 0.8 2.1 2.0 2.6 2.1

Do Not Use Central Air-Conditioning.................. 45.2 6.2 13.7 12.2 9.0 4.1

Summer 2005 Temperature Settings

Higher Temperature Settings

Daytime When No One is Home

Yes................................................................. 0.5 N QQQQ

No.................................................................. 50.8 2.9 8.5 12.1 10.2 17.1

Unknown........................................................ 14.5 1.8 3.7 2.9 4.7 1.4

Do Not Use Central Air-Conditioning.............. 45.2 6.2 13.7 12.2 9.0 4.1

At Night During Sleeping Hours

Yes................................................................. 7.3 0.3 1.2 1.5 1.4 2.9

No.................................................................. 44.3 2.6 7.5 10.8 9.0 14.4

Unknown........................................................ 14.2 1.8 3.7 2.8 4.6 1.4

Do Not Use Central Air-Conditioning.................. 45.2 6.2 13.7 12.2 9.0 4.1

Daytime Setting When Someone is Home

Air Conditioner Turned On................................. 52.0 3.0 8.7 12.3 10.6 17.4

69 Degrees or Less........................................ 4.8 0.3 1.0 1.7 1.1 0.6

70 Degrees..................................................... 7.2 0.5 1.3 2.1 1.6 1.8

71 to 73 Degrees............................................ 8.8 0.5 2.0 2.2 2.0 2.1

74 to 76 Degrees............................................ 16.5 1.3 2.5 3.9 3.2 5.6

77 to 79 Degrees............................................ 11.1 0.4 1.6 1.8 2.1 5.2

80 Degrees or More........................................ 3.7 Q 0.4 0.7 0.5 2.1

Don't Know/No Answer................................... 1.1 Q Q 0.3 0.3 Q

Do Not Use Central Air Conditioning.................. 45.2 6.2 13.7 12.2 9.0 4.1

Daytime Setting When No On is at Home

Air Conditioner Turned On................................. 49.5 2.7 8.2 12.1 9.5 17.0

69 Degrees or Less........................................ 3.6 Q 0.8 1.2 0.8 0.6

70 Degrees..................................................... 5.2 0.3 1.0 1.7 1.1 1.1

71 to 73 Degrees............................................ 6.0 0.3 1.1 1.8 1.4 1.4

74 to 76 Degrees............................................ 13.8 1.2 2.4 3.6 2.6 4.0

77 to 79 Degrees............................................ 10.7 0.6 1.7 2.1 1.7 4.7

80 Degrees or More........................................ 10.2 0.3 1.2 1.6 2.0 5.2

Don't Know/No Answer................................... 1.6 Q 0.3 0.3 0.6 Q

Air-Conditioner Turned Off................................. 2.0 Q 0.4 Q 0.8 0.4

Do Not Use Central Air Conditioning.................. 45.2 6.2 13.7 12.2 9.0 4.1

Energy Information Administration

2005 Residential Energy Consumption Survey: Preliminary Housing Characteristics Tables
 Million U.S. Housing Units

Table HC9.7 Air-Conditioning Usage Indicators by Climate Zone, 2005

Air-Conditioning Usage Indicators

2,000 CDD 

or More

and Less 

than 4,000 

HDD

Less than 2,000 CDD and --

Greater than 

7,000 HDD

5,500 to 

7,000 HDD

4,000 to 

5,499 HDD

Less than 

4,000 HDD

Housing 

Units 

(millions)

Climate Zone1

Setting During Seeping Hours

Air Conditioner Turned On 51.0 2.8 8.6 12.2 9.9 17.4

69 Degrees or Less........................................ 5.7 0.4 1.2 1.8 1.5 0.9

70 Degrees..................................................... 7.7 0.4 1.5 2.2 1.6 1.9

71 to 73 Degrees............................................ 8.3 0.4 1.7 2.3 1.6 2.4

74 to 76 Degrees............................................ 15.5 1.2 2.5 3.6 2.8 5.5

77 to 79 Degrees............................................ 9.7 0.4 1.3 1.7 1.6 4.6

80 Degrees or More........................................ 4.1 Q 0.5 0.7 0.9 2.0

Don't Know/No Answer................................... 1.3 Q 0.2 0.2 0.5 Q

Air-Conditioner Turned Off................................. 0.8 Q Q Q 0.4 Q

Do Not Use Central Air Conditioning.................. 45.2 6.2 13.7 12.2 9.0 4.1

Dehumidifier Use Each Year

Use a Humidifier.................................................... 13.3 3.0 5.6 3.4 0.7 0.5

1 to 3 Months Each Year.................................... 5.1 1.2 2.3 1.1 Q Q

4 to 6 Months Each Year.................................... 4.4 1.3 2.0 1.0 Q Q

7 to 9 Months Each Year.................................... 0.9 Q 0.4 0.3 Q Q

10 to 11 Months................................................. Q N Q Q Q N

Turned on All Year Long.................................... 2.6 0.4 0.9 0.9 0.3 Q

Do Not Use a Dehumidifier.................................... 97.8 7.9 20.4 23.9 23.2 22.3

Window/Wall Air Conditioners

Frequency Most Used Unit Was Used

Never................................................................. 0.6 QQQQQ

Only a Few Times When Needed....................... 12.1 1.5 4.2 3.8 1.7 0.9

Quite a Bit.......................................................... 7.5 1.0 2.6 2.1 0.9 0.9

All Summer........................................................ 8.6 0.4 2.4 2.7 1.3 1.7

Energy Star Wall/Window (Most-Used) Unit

Yes.................................................................... 4.6 0.5 1.5 1.4 0.5 0.7

No...................................................................... 2.7 0.3 0.8 0.7 0.3 0.5

Don't Know......................................................... 7.0 0.7 2.4 2.2 1.0 0.7

Unit is More Than 4 Years Old........................... 14.6 1.6 4.6 4.4 2.1 1.8

Use a Swamp Cooler (Asked Only in Arid Areas)

Yes........................................................................ 3.4 0.3 0.8 Q 1.1 0.5

No.......................................................................... 41.9 2.2 3.8 3.8 17.7 14.5

Not Asked.............................................................. 65.8 8.5 21.5 22.8 5.3 7.9

 1. One of five climatically distinct areas, determined according to the 30-year average (1971-2000) of the annual heating and cooling 

degree-days. A household is assigned to a climate zone according to the 30-year average annual degree-days for an appropriate nearby 

weather station.

 2. In the 2005 RECS 1.5 million housing units reported having both central and window/wall air conditioners.

 3. The number of housing units using air-conditioning includes a small, undetermined number of housing units where the fuel for 

central air-conditioning was some fuel other than electricity; these housing units were treated as if the air-conditioning fuel was electricity.

 Q = Data withheld either because the Relative Standard Error (RSE) was greater than 50 percent or fewer than 10 households were 

sampled.

 N = No cases in reporting sample.

 Notes: ● Because of rounding, data may not sum to totals. ● See Glossary for definition of terms used in these tables.

 Source: Energy Information Administration, Office of Energy Markets and End Use, Forms EIA-457 A, B, C of the 2005 

Residential Energy Consumption Survey.

Energy Information Administration

2005 Residential Energy Consumption Survey: Preliminary Housing Characteristics Tables