| 2000 | 2017 | 2018 | 2019 | 2020 | 2021 | ||
|---|---|---|---|---|---|---|---|
| Total Heating System Stock (thousands) | 1,641.2 | 2,072.7 | 2,107.3 | 2,143.6 | 2,182.0 | 2,223.2 | |
Heating System Stock by Building Type (thousands) | |||||||
| Single Detached | 886.2 | 1,013.5 | 1,021.2 | 1,028.8 | 1,035.3 | 1,042.8 | |
| Single Attached | 174.1 | 259.5 | 264.7 | 269.9 | 275.3 | 281.9 | |
| Apartments | 518.7 | 728.5 | 749.8 | 772.4 | 797.8 | 823.8 | |
| Mobile Homes | 62.2 | 71.1 | 71.7 | 72.6 | 73.6 | 74.6 | |
Shares (%) | |||||||
| Single Detached | 54.0 | 48.9 | 48.5 | 48.0 | 47.4 | 46.9 | |
| Single Attached | 10.6 | 12.5 | 12.6 | 12.6 | 12.6 | 12.7 | |
| Apartments | 31.6 | 35.1 | 35.6 | 36.0 | 36.6 | 37.1 | |
| Mobile Homes | 3.8 | 3.4 | 3.4 | 3.4 | 3.4 | 3.4 | |
Heating System Stock by Heating System Type (thousands) | |||||||
| Heating Oil – Normal Efficiency | 54.7 | 2.1 | 1.9 | 1.4 | 2.0 | 0.9 | |
| Heating Oil – Medium Efficiency | 36.5 | 72.4 | 70.7 | 69.4 | 66.8 | 65.6 | |
| Heating Oil – High Efficiency | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Natural Gas – Normal Efficiency | 404.2 | 0.2 | 0.1 | 0.1 | 0.0 | 0.0 | |
| Natural Gas – Medium Efficiency | 314.6 | 427.5 | 401.9 | 375.8 | 349.5 | 323.7 | |
| Natural Gas – High Efficiency | 170.2 | 507.6 | 536.2 | 571.7 | 608.4 | 647.1 | |
| Electric | 460.9 | 801.1 | 831.3 | 855.1 | 880.0 | 905.5 | |
| Heat Pump | 37.2 | 70.0 | 72.3 | 74.7 | 77.4 | 80.0 | |
| Other1 | 30.5 | 19.6 | 18.9 | 18.7 | 18.6 | 18.5 | |
| Wood | 22.7 | 24.8 | 24.5 | 24.8 | 25.1 | 25.4 | |
Dual Systems | |||||||
| Wood/Electric | 65.0 | 84.9 | 86.0 | 87.2 | 88.5 | 89.7 | |
| Wood/Heating Oil | 25.2 | 33.0 | 33.4 | 33.9 | 34.4 | 34.9 | |
| Natural Gas/Electric | 13.4 | 20.0 | 20.3 | 20.7 | 21.1 | 21.5 | |
| Heating Oil/Electric | 6.1 | 9.6 | 9.8 | 10.0 | 10.2 | 10.4 | |
Shares (%) | |||||||
| Heating Oil – Normal Efficiency | 3.3 | 0.1 | 0.1 | 0.1 | 0.1 | 0.0 | |
| Heating Oil – Medium Efficiency | 2.2 | 3.5 | 3.4 | 3.2 | 3.1 | 3.0 | |
| Heating Oil – High Efficiency | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Natural Gas – Normal Efficiency | 24.6 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Natural Gas – Medium Efficiency | 19.2 | 20.6 | 19.1 | 17.5 | 16.0 | 14.6 | |
| Natural Gas – High Efficiency | 10.4 | 24.5 | 25.4 | 26.7 | 27.9 | 29.1 | |
| Electric | 28.1 | 38.6 | 39.5 | 39.9 | 40.3 | 40.7 | |
| Heat Pump | 2.3 | 3.4 | 3.4 | 3.5 | 3.5 | 3.6 | |
| Other1 | 1.9 | 0.9 | 0.9 | 0.9 | 0.9 | 0.8 | |
| Wood | 1.4 | 1.2 | 1.2 | 1.2 | 1.1 | 1.1 | |
Dual Systems | |||||||
| Wood/Electric | 4.0 | 4.1 | 4.1 | 4.1 | 4.1 | 4.0 | |
| Wood/Heating Oil | 1.5 | 1.6 | 1.6 | 1.6 | 1.6 | 1.6 | |
| Natural Gas/Electric | 0.8 | 1.0 | 1.0 | 1.0 | 1.0 | 1.0 | |
| Heating Oil/Electric | 0.4 | 0.5 | 0.5 | 0.5 | 0.5 | 0.5 | |