| 2000 | 2018 | 2019 | 2020 | 2021 | ||
|---|---|---|---|---|---|---|
| Total Single Attached Heating System Stock (thousands) | 236.6 | 323.5 | 328.2 | 333.1 | 339.0 | |
Heating System Stock by Heating System Type (thousands) | ||||||
| Heating Oil – Normal Efficiency | 4.8 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Heating Oil – Medium Efficiency | 22.6 | 17.3 | 15.6 | 13.6 | 11.6 | |
| Heating Oil – High Efficiency | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Natural Gas – Normal Efficiency | 9.4 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Natural Gas – Medium Efficiency | 1.8 | 1.4 | 1.3 | 1.3 | 1.2 | |
| Natural Gas – High Efficiency | 2.1 | 15.0 | 15.4 | 15.9 | 16.3 | |
| Electric | 149.8 | 232.9 | 237.7 | 242.9 | 249.0 | |
| Heat Pump | 7.8 | 16.1 | 16.7 | 17.4 | 18.2 | |
| Other1 | 0.3 | 1.2 | 1.3 | 1.4 | 1.5 | |
| Wood | 15.4 | 8.4 | 8.2 | 8.1 | 7.9 | |
Dual Systems | ||||||
| Wood/Electric | 8.4 | 10.3 | 10.5 | 10.7 | 10.9 | |
| Wood/Heating Oil | 3.3 | 4.0 | 4.1 | 4.2 | 4.3 | |
| Natural Gas/Electric | 0.4 | 0.7 | 0.7 | 0.7 | 0.8 | |
| Heating Oil/Electric | 10.5 | 16.1 | 16.5 | 16.9 | 17.4 | |
Shares (%) | ||||||
| Heating Oil – Normal Efficiency | 2.0 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Heating Oil – Medium Efficiency | 9.6 | 5.3 | 4.7 | 4.1 | 3.4 | |
| Heating Oil – High Efficiency | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Natural Gas – Normal Efficiency | 4.0 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Natural Gas – Medium Efficiency | 0.7 | 0.4 | 0.4 | 0.4 | 0.4 | |
| Natural Gas – High Efficiency | 0.9 | 4.6 | 4.7 | 4.8 | 4.8 | |
| Electric | 63.3 | 72.0 | 72.4 | 72.9 | 73.4 | |
| Heat Pump | 3.3 | 5.0 | 5.1 | 5.2 | 5.4 | |
| Other1 | 0.1 | 0.4 | 0.4 | 0.4 | 0.4 | |
| Wood | 6.5 | 2.6 | 2.5 | 2.4 | 2.3 | |
Dual Systems | ||||||
| Wood/Electric | 3.6 | 3.2 | 3.2 | 3.2 | 3.2 | |
| Wood/Heating Oil | 1.4 | 1.2 | 1.3 | 1.3 | 1.3 | |
| Natural Gas/Electric | 0.2 | 0.2 | 0.2 | 0.2 | 0.2 | |
| Heating Oil/Electric | 4.4 | 5.0 | 5.0 | 5.1 | 5.1 | |