Table HC9.8 Water Heating Characteristics by Climate Zone, 2005

 Million U.S. Housing Units

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

Number of Water Heaters

1.............................................................................. 106.3 10.3 25.2 26.2 23.0 21.7

2 or More................................................................. 3.7 0.4 0.7 0.6 0.9 1.1

Do Not Use Hot Water............................................ 1.1 0.3 0.2 0.5 Q Q

Housing Units Served by Main Water Heater

One Housing Unit.................................................... 99.7 10.1 22.9 23.0 22.0 21.7

Two or More Housing Units..................................... 10.3 0.5 2.9 3.8 1.9 1.1

Do Not Use Hot Water............................................ 1.1 0.3 0.2 0.5 Q Q

Main Water Heating Fuel

Electric.................................................................... 43.1 3.4 6.7 10.2 8.7 14.1

For One Housing Unit.......................................... 40.3 3.3 6.1 9.4 8.0 13.4

For Two or More Housing Units........................... 2.7 Q 0.6 0.8 0.7 0.7

Natural Gas............................................................. 58.7 5.5 16.7 14.2 14.2 8.1

For One Housing Unit.......................................... 52.5 5.2 14.6 12.0 13.1 7.6

For Two or More Housing Units........................... 6.2 0.4 2.1 2.2 1.1 0.4

Fuel Oil................................................................... 4.0 Q 1.6 1.7 N N

For One Housing Unit.......................................... 3.0 Q 1.4 0.9 N N

For Two or More Housing Units........................... 1.1 Q 0.2 0.8 N N

Propane/LPG.......................................................... 4.0 0.9 0.8 0.8 1.0 0.5

Other....................................................................... 0.2 Q Q N Q Q

Do Not Use Hot Water............................................ 1.1 0.3 0.2 0.5 Q Q

Age of Main Water Heater

Used by One Housing Unit

Less than 2 Years............................................... 14.7 1.5 3.7 2.4 3.6 3.4

2 to 4 Years......................................................... 18.6 1.8 3.9 3.9 4.3 4.6

5 to 9 Years......................................................... 25.5 2.7 5.5 6.3 5.6 5.5

10 to 19 Years..................................................... 20.1 2.5 4.4 5.0 4.7 3.6

20 Years or More................................................. 6.8 0.6 1.8 1.6 1.2 1.7

Don't Know.......................................................... 12.0 0.8 3.2 3.0 2.4 2.6

No Separate Water Heater.................................. 1.9 Q 0.4 0.8 0.3 0.3

Used by Two or More Housing Units

Less than 2 Years............................................... 0.3 N Q Q Q N

2 to 4 Years......................................................... 0.5 Q Q Q Q Q

5 to 9 Years......................................................... 0.5 Q Q Q Q Q

10 to 19 Years..................................................... 0.6 Q 0.2 Q Q Q

20 Years or More................................................. 0.6 Q Q Q 0.2 Q

Don't Know.......................................................... 4.4 0.3 1.4 1.9 0.4 0.4

No Separate Water Heater.................................. 3.4 Q 0.8 1.4 0.8 0.3

Water Heating Characteristics

Climate Zone1

2,000 CDD 

or More

and Less 

than 4,000 

HDD

Less than 2,000 CDD and --

Less than 

4,000 HDD

Greater than 

7,000 HDD

5,500 to 

7,000 HDD

4,000 to 

5,499 HDD

Housing 

Units 

(millions)

Energy Information Administration

2005 Residential Energy Consumption Survey: Preliminary Housing Characterisics Tables
Table HC9.8 Water Heating Characteristics by Climate Zone, 2005

 Million U.S. Housing Units

Water Heating Characteristics

Climate Zone1

2,000 CDD 

or More

and Less 

than 4,000 

HDD

Less than 2,000 CDD and --

Less than 

4,000 HDD

Greater than 

7,000 HDD

5,500 to 

7,000 HDD

4,000 to 

5,499 HDD

Housing 

Units 

(millions)

Size of Main Water Heater

Used by One Housing Unit

Small (30 gallons or less).................................... 17.1 1.3 3.1 3.5 3.7 5.5

Medium (31 to 49 gallons)................................... 52.4 5.3 13.3 11.7 11.9 10.2

Large (50 gallons or more).................................. 27.1 3.1 5.8 6.8 6.0 5.5

Tankless water heater......................................... 1.1 0.3 0.3 0.3 Q Q

No Separate Water Heater.................................. 1.9 Q 0.4 0.8 0.3 0.3

Used by Two or More Housing Units

Small (30 gallons or less).................................... 1.4 Q 0.3 0.6 Q Q

Medium (31 to 49 gallons)................................... 2.4 Q 0.8 1.0 0.3 0.3

Large (50 gallons or more).................................. 2.8 Q 1.0 0.7 0.6 0.3

Tankless water heater......................................... 0.2 Q Q Q N N

No Separate Water Heater.................................. 3.4 Q 0.8 1.4 0.8 0.3

Other Water Heating

Hot Tubs or Spas.................................................. 6.7 0.9 1.2 1.4 1.6 1.6

Electricity............................................................. 5.3 0.8 1.1 1.1 1.1 1.2

Natural Gas......................................................... 1.2 Q Q Q 0.6 0.3

Swimming Pools................................................... 1.9 Q Q 0.4 0.5 0.7

Natural Gas......................................................... 1.2 Q Q Q 0.4 0.4

Electricity............................................................. 0.4 N N Q Q Q

Propane/LPG....................................................... 0.3 Q Q Q Q Q

Some Other Fuel................................................. Q N Q N N N

Electric Water Beds.............................................. 2.2 0.3 0.7 0.5 Q 0.5

1.......................................................................... 1.9 0.2 0.7 0.4 Q 0.4

2 or More............................................................. 0.3 Q Q Q Q Q

Heaters Used all Year.................................... 1.7 0.2 0.7 0.4 Q Q

1................................................................... 1.5 Q 0.6 0.4 Q Q

2 or More...................................................... 0.3 Q Q Q Q Q

 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.

 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 Characterisics Tables