| 2000 | 2018 | 2019 | 2020 | 2021 | ||
|---|---|---|---|---|---|---|
| Total Single Detached Heating System Stock (thousands) | 661.9 | 769.0 | 772.5 | 776.4 | 781.1 | |
Heating System Stock by Heating System Type (thousands) | ||||||
| Heating Oil – Normal Efficiency | 99.5 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Heating Oil – Medium Efficiency | 136.5 | 146.3 | 141.6 | 136.2 | 132.3 | |
| Heating Oil – High Efficiency | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Natural Gas – Normal Efficiency | 1.5 | 0.1 | 0.1 | 0.1 | 0.1 | |
| Natural Gas – Medium Efficiency | 3.5 | 2.7 | 2.5 | 2.1 | 1.8 | |
| Natural Gas – High Efficiency | 4.0 | 14.7 | 15.6 | 16.5 | 17.3 | |
| Electric | 238.4 | 423.4 | 429.8 | 436.4 | 442.5 | |
| Heat Pump | 17.0 | 31.3 | 32.0 | 33.0 | 33.9 | |
| Other1 | 7.1 | 10.3 | 10.3 | 10.5 | 10.7 | |
| Wood | 19.0 | 0.0 | 0.0 | 0.0 | 0.0 | |
Dual Systems | ||||||
| Wood/Electric | 69.2 | 69.7 | 70.0 | 70.5 | 71.0 | |
| Wood/Heating Oil | 62.5 | 64.9 | 65.0 | 65.5 | 65.8 | |
| Natural Gas/Electric | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Heating Oil/Electric | 3.6 | 5.5 | 5.6 | 5.7 | 5.8 | |
Shares (%) | ||||||
| Heating Oil – Normal Efficiency | 15.0 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Heating Oil – Medium Efficiency | 20.6 | 19.0 | 18.3 | 17.5 | 16.9 | |
| Heating Oil – High Efficiency | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Natural Gas – Normal Efficiency | 0.2 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Natural Gas – Medium Efficiency | 0.5 | 0.4 | 0.3 | 0.3 | 0.2 | |
| Natural Gas – High Efficiency | 0.6 | 1.9 | 2.0 | 2.1 | 2.2 | |
| Electric | 36.0 | 55.1 | 55.6 | 56.2 | 56.7 | |
| Heat Pump | 2.6 | 4.1 | 4.1 | 4.2 | 4.3 | |
| Other1 | 1.1 | 1.3 | 1.3 | 1.3 | 1.4 | |
| Wood | 2.9 | 0.0 | 0.0 | 0.0 | 0.0 | |
Dual Systems | ||||||
| Wood/Electric | 10.5 | 9.1 | 9.1 | 9.1 | 9.1 | |
| Wood/Heating Oil | 9.4 | 8.4 | 8.4 | 8.4 | 8.4 | |
| Natural Gas/Electric | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Heating Oil/Electric | 0.5 | 0.7 | 0.7 | 0.7 | 0.7 | |