Table HC4-1a. Air Conditioning by Climate Zone, 

 Million U.S. Households, 2001

Air Conditioning

Characteristics

RSE Column Factor:

Total

Climate Zone1

RSE

Row

Factors

Fewer than 2,000 CDD and --

2,000 CDD

or More

and Fewer

than

4,000 HDD

More than

7,000 HDD

5,500 to

7,000 HDD

4,000 to

5,499 HDD

Fewer than

4,000 HDD

0.4 2.1 1.0 0.9 1.5 1.0

Total Households With

Air-Conditioning ........................... 82.9 5.4 20.9 20.2 14.2 22.1 8.1

 Air Conditioners Not Used ............ 2.1 Q 0.4 0.3 0.8 0.4 23.2

Households Using Electric

Air-Conditioning2 .......................... 80.8 5.3 20.5 19.9 13.4 21.8 8.2

Type of Electric Air-Conditioning

Used

 Central Air-Conditioning3 .............. 57.5 3.1 12.9 12.7 10.5 18.2 9.2

 Without a Heat Pump .................. 46.2 3.0 12.1 9.8 7.0 14.3 10.7

 With a Heat Pump ....................... 11.3 Q 0.9 2.9 3.5 3.9 19.5

 Room Air-Conditioning .................. 23.3 2.2 7.6 7.2 2.9 3.6 11.3

 1 Unit .......................................... 12.8 1.4 4.5 3.4 1.9 1.5 13.5

 2 Units ......................................... 7.5 0.5 2.2 2.5 0.8 1.4 13.8

 3 or More Units ........................... 3.0 0.2 0.8 1.2 0.2 0.7 20.1

Number of Rooms AirConditioned in Summer 2001

 One or Two ................................... 12.3 0.8 4.4 3.6 1.8 1.8 12.1

 Three ............................................ 9.2 0.9 2.2 2.2 1.6 2.4 16.5

 Four ............................................. 12.0 0.8 2.6 3.1 1.7 3.8 14.4

 Five or More .................................. 47.3 2.8 11.3 11.0 8.4 13.8 9.6

Percentage of Rooms

Air-Conditioned

 100% ............................................. 58.8 3.3 13.5 13.7 10.3 18.0 9.4

 50% to 99% .................................. 12.1 1.1 3.2 3.2 1.7 2.8 13.0

 25% to 49% .................................. 6.4 0.5 2.3 2.1 0.8 0.7 15.0

 1% to 24% .................................... 3.5 0.3 1.5 0.8 0.5 0.3 18.9

Large Tree(s) that

Shade the Home

 Yes ................................................ 41.5 2.6 10.0 9.5 6.9 12.5 10.5

 No ................................................. 39.3 2.6 10.5 10.4 6.4 9.3 10.1

Central Air-Conditioner Age

(excludes systems for more than

one housing unit)

 Less than 2 Years ......................... 6.1 0.4 1.1 1.4 1.2 1.9 17.0

 2 to 4 Years .................................. 10.1 0.5 2.6 2.2 2.0 2.9 15.5

 5 to 9 Years .................................. 15.4 0.9 3.2 3.3 3.0 5.0 13.1

 10 to 19 Years .............................. 15.0 0.8 3.7 3.1 2.8 4.6 14.1

 20 Years or More .......................... 5.7 0.5 1.4 1.1 1.0 1.7 17.9

 Don’t Know ................................... 3.7 Q 0.6 1.0 0.4 1.7 23.3

Central Air-Conditioning Use

 Only a Few Times ......................... 16.8 1.8 5.9 4.2 2.9 1.9 12.5

 Quite a Bit ..................................... 12.1 0.5 3.4 3.2 1.6 3.4 13.6

 All Summer ................................... 28.4 0.7 3.6 5.3 6.0 12.8 12.2

See footnotes at end of table.

Energy Information Administration

2001 Residential Energy Consumption Survey: Housing Characteristics Tables
Table HC4-1a. Air Conditioning by Climate Zone, 

 Million U.S. Households, 2001 (Continued)

Air Conditioning

Characteristics

RSE Column Factor:

Total

Climate Zone1

RSE

Row

Factors

Fewer than 2,000 CDD and --

2,000 CDD

or More

and Fewer

than

4,000 HDD

More than

7,000 HDD

5,500 to

7,000 HDD

4,000 to

5,499 HDD

Fewer than

4,000 HDD

0.4 2.1 1.0 0.9 1.5 1.0

Pays for Electricity for Central

Air-Conditioning

 Yes ................................................ 55.5 3.1 12.5 12.1 10.3 17.4 9.4

 No ................................................. 2.0 Q 0.4 0.6 Q 0.8 30.6

Age of Most-Used Room Air

Conditioner

 Less than 2 Years ......................... 3.1 0.3 1.1 0.9 0.4 0.4 21.1

 2 to 4 Years .................................. 5.3 0.3 1.5 2.0 0.5 1.0 15.4

 5 to 9 Years .................................. 6.4 0.7 1.8 1.9 0.8 1.2 15.4

 10 or 19 Years .............................. 4.3 0.5 1.5 1.2 0.5 0.5 19.1

 20 or More Years .......................... 2.0 0.2 0.7 0.6 Q 0.3 28.5

 Don’t Know ................................... 2.2 0.2 0.9 0.5 0.4 Q 25.9

Room Air-Conditioning Use

 Only a Few Times ......................... 13.6 1.4 5.3 4.0 1.4 1.4 12.4

 Quite a Bit ..................................... 5.0 0.5 1.3 1.7 0.7 0.8 19.9

 All Summer ................................... 4.7 0.2 1.0 1.4 0.8 1.3 21.0

Pays for Electricity for Room

Air-Conditioning

 Yes ................................................ 21.9 2.1 7.1 6.7 2.7 3.3 11.4

 No ................................................. 1.5 Q 0.5 0.5 Q Q 40.3

1 One of five climatically distinct areas, determined according to the 30-year average (1961-1990) of the annual heating and cooling degree-days. For this

report, the heating or cooling degree-days are a measure of how cold or how hot a location is over a period of one year, relative to a base temperature of 65

degrees Fahrenheit. A household is assigned to a climate zone according to the 30-year average annual degree-days for an appropriate nearby weather station. 2 The number of households, where the end use is electric air-conditioning, does not include households that did not use their equipment (2.1 million). It does

include the small number of households where the fuel for central air-conditioning equipment was something other than electricity; those households were treated

as if the fuel was electricity. 3 The 2001 RECS reported 800,000 households having both central air-conditioning and room/wall air-conditioners, with 600,000 households using both central

air-conditioning and 200,000 households using only room/wall air-conditioners. These room/wall air-conditioners are not included in the count of 23.3 million

households using room/wall air-conditioners. Note: This applies to all occurrences of central air-conditioning.

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

Notes: • To obtain the RSE percentage for any table cell, multiply the corresponding column and row factors. • Because of rounding, data may not sum to totals.

 • See "Glossary" for definition of terms used in this report.

Source: Energy Information Administration, Office of Energy Markets and End Use, Forms EIA-457 A, B, C of the 2001 Residential Energy Consumption Survey.

Energy Information Administration

2001 Residential Energy Consumption Survey: Housing Characteristics Tables