| 2000 | 2018 | 2019 | 2020 | 2021 | ||
|---|---|---|---|---|---|---|
| Total Heating System Stock (thousands) | 1,159.1 | 1,727.8 | 1,753.2 | 1,777.8 | 1,803.1 | |
Heating System Stock by Building Type (thousands) | ||||||
| Single Detached | 734.0 | 1,038.5 | 1,047.7 | 1,056.7 | 1,066.5 | |
| Single Attached | 133.7 | 242.2 | 249.1 | 255.3 | 260.9 | |
| Apartments | 243.7 | 380.7 | 389.6 | 398.5 | 407.7 | |
| Mobile Homes | 47.7 | 66.3 | 66.9 | 67.4 | 68.0 | |
Shares (%) | ||||||
| Single Detached | 63.3 | 60.1 | 59.8 | 59.4 | 59.1 | |
| Single Attached | 11.5 | 14.0 | 14.2 | 14.4 | 14.5 | |
| Apartments | 21.0 | 22.0 | 22.2 | 22.4 | 22.6 | |
| Mobile Homes | 4.1 | 3.8 | 3.8 | 3.8 | 3.8 | |
Heating System Stock by Heating System Type (thousands) | ||||||
| Heating Oil – Normal Efficiency | 6.3 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Heating Oil – Medium Efficiency | 2.1 | 4.1 | 3.9 | 3.8 | 3.7 | |
| Heating Oil – High Efficiency | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Natural Gas – Normal Efficiency | 541.5 | 0.1 | 0.0 | 0.0 | 0.0 | |
| Natural Gas – Medium Efficiency | 489.2 | 697.6 | 660.3 | 622.0 | 582.4 | |
| Natural Gas – High Efficiency | 55.4 | 762.8 | 815.8 | 868.7 | 923.9 | |
| Electric | 18.5 | 189.5 | 198.1 | 206.7 | 214.9 | |
| Heat Pump | 16.8 | 41.7 | 43.0 | 44.3 | 45.7 | |
| Other1 | 16.8 | 13.4 | 13.2 | 13.1 | 12.9 | |
| Wood | 1.8 | 0.8 | 0.8 | 0.7 | 0.7 | |
Dual Systems | ||||||
| Wood/Electric | 1.5 | 2.3 | 2.3 | 2.4 | 2.4 | |
| Wood/Heating Oil | 5.0 | 7.8 | 7.9 | 8.1 | 8.2 | |
| Natural Gas/Electric | 4.2 | 7.7 | 7.9 | 8.0 | 8.2 | |
| Heating Oil/Electric | 0.1 | 0.1 | 0.1 | 0.1 | 0.1 | |
Shares (%) | ||||||
| Heating Oil – Normal Efficiency | 0.5 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Heating Oil – Medium Efficiency | 0.2 | 0.2 | 0.2 | 0.2 | 0.2 | |
| Heating Oil – High Efficiency | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Natural Gas – Normal Efficiency | 46.7 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Natural Gas – Medium Efficiency | 42.2 | 40.4 | 37.7 | 35.0 | 32.3 | |
| Natural Gas – High Efficiency | 4.8 | 44.1 | 46.5 | 48.9 | 51.2 | |
| Electric | 1.6 | 11.0 | 11.3 | 11.6 | 11.9 | |
| Heat Pump | 1.5 | 2.4 | 2.5 | 2.5 | 2.5 | |
| Other1 | 1.4 | 0.8 | 0.8 | 0.7 | 0.7 | |
| Wood | 0.2 | 0.0 | 0.0 | 0.0 | 0.0 | |
Dual Systems | ||||||
| Wood/Electric | 0.1 | 0.1 | 0.1 | 0.1 | 0.1 | |
| Wood/Heating Oil | 0.4 | 0.5 | 0.5 | 0.5 | 0.5 | |
| Natural Gas/Electric | 0.4 | 0.4 | 0.4 | 0.5 | 0.5 | |
| Heating Oil/Electric | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | |