| 2000 | 2018 | 2019 | 2020 | 2021 | ||
|---|---|---|---|---|---|---|
| Total Single Detached Heating System Stock (thousands) | 869.3 | 998.5 | 1,005.6 | 1,011.6 | 1,018.6 | |
Heating System Stock by Heating System Type (thousands) | ||||||
| Heating Oil – Normal Efficiency | 15.3 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Heating Oil – Medium Efficiency | 14.9 | 23.0 | 21.7 | 20.2 | 18.7 | |
| Heating Oil – High Efficiency | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Natural Gas – Normal Efficiency | 212.7 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Natural Gas – Medium Efficiency | 161.2 | 185.2 | 171.4 | 157.6 | 144.1 | |
| Natural Gas – High Efficiency | 90.3 | 240.4 | 253.5 | 266.2 | 279.7 | |
| Electric | 235.6 | 362.6 | 368.5 | 373.8 | 379.2 | |
| Heat Pump | 24.8 | 45.0 | 46.3 | 47.5 | 48.8 | |
| Other1 | 14.7 | 6.8 | 6.6 | 6.4 | 6.3 | |
| Wood | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | |
Dual Systems | ||||||
| Wood/Electric | 60.4 | 79.6 | 80.7 | 81.9 | 83.1 | |
| Wood/Heating Oil | 21.1 | 28.0 | 28.4 | 28.8 | 29.2 | |
| Natural Gas/Electric | 12.4 | 18.4 | 18.7 | 19.0 | 19.4 | |
| Heating Oil/Electric | 6.0 | 9.6 | 9.8 | 10.0 | 10.2 | |
Shares (%) | ||||||
| Heating Oil – Normal Efficiency | 1.8 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Heating Oil – Medium Efficiency | 1.7 | 2.3 | 2.2 | 2.0 | 1.8 | |
| Heating Oil – High Efficiency | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Natural Gas – Normal Efficiency | 24.5 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Natural Gas – Medium Efficiency | 18.5 | 18.5 | 17.0 | 15.6 | 14.2 | |
| Natural Gas – High Efficiency | 10.4 | 24.1 | 25.2 | 26.3 | 27.5 | |
| Electric | 27.1 | 36.3 | 36.6 | 37.0 | 37.2 | |
| Heat Pump | 2.8 | 4.5 | 4.6 | 4.7 | 4.8 | |
| Other1 | 1.7 | 0.7 | 0.7 | 0.6 | 0.6 | |
| Wood | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | |
Dual Systems | ||||||
| Wood/Electric | 6.9 | 8.0 | 8.0 | 8.1 | 8.2 | |
| Wood/Heating Oil | 2.4 | 2.8 | 2.8 | 2.8 | 2.9 | |
| Natural Gas/Electric | 1.4 | 1.8 | 1.9 | 1.9 | 1.9 | |
| Heating Oil/Electric | 0.7 | 1.0 | 1.0 | 1.0 | 1.0 | |