| 2000 | 2001 | 2002 | 2003 | 2004 | 2005 | 2006 | 2007 | 2008 | ||
|---|---|---|---|---|---|---|---|---|---|---|
| Total Single Detached Heating System Stock (thousands) | 733.7 | 750.2 | 770.0 | 790.9 | 810.7 | 833.1 | 856.4 | 882.4 | 902.4 | |
Heating System Stock by Heating System Type (thousands) | ||||||||||
| Heating Oil – Normal Efficiency | 3.6 | 3.1 | 2.6 | 2.2 | 1.7 | 1.3 | 0.9 | 0.5 | 0.2 | |
| Heating Oil – Medium Efficiency | 1.3 | 1.7 | 2.1 | 2.6 | 3.0 | 3.4 | 3.7 | 4.1 | 4.3 | |
| Heating Oil – High Efficiency | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Natural Gas – Normal Efficiency | 328.2 | 304.6 | 279.1 | 255.0 | 222.0 | 192.1 | 163.2 | 136.2 | 112.5 | |
| Natural Gas – Medium Efficiency | 320.8 | 348.7 | 380.3 | 408.6 | 442.2 | 472.5 | 501.2 | 526.8 | 539.4 | |
| Natural Gas – High Efficiency | 37.5 | 46.8 | 58.8 | 71.0 | 87.4 | 104.3 | 122.6 | 144.9 | 172.1 | |
| Electric | 11.4 | 13.1 | 13.8 | 17.1 | 18.4 | 22.2 | 25.9 | 29.5 | 32.1 | |
| Heat Pump | 13.5 | 14.5 | 15.5 | 16.5 | 17.6 | 18.8 | 20.0 | 21.4 | 22.6 | |
| Other1 | 10.6 | 10.6 | 10.7 | 10.7 | 10.8 | 10.8 | 10.8 | 10.9 | 10.9 | |
| Wood | 0.5 | 0.5 | 0.4 | 0.3 | 0.3 | 0.2 | 0.2 | 0.1 | 0.1 | |
Dual Systems | ||||||||||
| Wood/Electric | 0.9 | 1.0 | 1.0 | 1.0 | 1.1 | 1.1 | 1.1 | 1.2 | 1.2 | |
| Wood/Heating Oil | 3.1 | 3.3 | 3.4 | 3.5 | 3.6 | 3.7 | 3.8 | 3.9 | 4.0 | |
| Natural Gas/Electric | 2.1 | 2.2 | 2.4 | 2.5 | 2.6 | 2.7 | 2.8 | 2.9 | 3.0 | |
| Heating Oil/Electric | 0.1 | 0.1 | 0.1 | 0.1 | 0.1 | 0.1 | 0.1 | 0.1 | 0.1 | |
Shares (%) | ||||||||||
| Heating Oil – Normal Efficiency | 0.5 | 0.4 | 0.3 | 0.3 | 0.2 | 0.2 | 0.1 | 0.1 | 0.0 | |
| Heating Oil – Medium Efficiency | 0.2 | 0.2 | 0.3 | 0.3 | 0.4 | 0.4 | 0.4 | 0.5 | 0.5 | |
| Heating Oil – High Efficiency | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Natural Gas – Normal Efficiency | 44.7 | 40.6 | 36.2 | 32.2 | 27.4 | 23.1 | 19.1 | 15.4 | 12.5 | |
| Natural Gas – Medium Efficiency | 43.7 | 46.5 | 49.4 | 51.7 | 54.5 | 56.7 | 58.5 | 59.7 | 59.8 | |
| Natural Gas – High Efficiency | 5.1 | 6.2 | 7.6 | 9.0 | 10.8 | 12.5 | 14.3 | 16.4 | 19.1 | |
| Electric | 1.6 | 1.8 | 1.8 | 2.2 | 2.3 | 2.7 | 3.0 | 3.3 | 3.6 | |
| Heat Pump | 1.8 | 1.9 | 2.0 | 2.1 | 2.2 | 2.3 | 2.3 | 2.4 | 2.5 | |
| Other1 | 1.4 | 1.4 | 1.4 | 1.4 | 1.3 | 1.3 | 1.3 | 1.2 | 1.2 | |
| Wood | 0.1 | 0.1 | 0.1 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | |
Dual Systems | ||||||||||
| Wood/Electric | 0.1 | 0.1 | 0.1 | 0.1 | 0.1 | 0.1 | 0.1 | 0.1 | 0.1 | |
| Wood/Heating Oil | 0.4 | 0.4 | 0.4 | 0.4 | 0.4 | 0.4 | 0.4 | 0.4 | 0.4 | |
| Natural Gas/Electric | 0.3 | 0.3 | 0.3 | 0.3 | 0.3 | 0.3 | 0.3 | 0.3 | 0.3 | |
| Heating Oil/Electric | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | |