| 2000 | 2018 | 2019 | 2020 | 2021 | ||
|---|---|---|---|---|---|---|
| Total Single Detached Heating System Stock (thousands) | 886.2 | 1,021.2 | 1,028.8 | 1,035.3 | 1,042.8 | |
Heating System Stock by Heating System Type (thousands) | ||||||
| Heating Oil – Normal Efficiency | 21.6 | 1.0 | 0.6 | 1.1 | 0.4 | |
| Heating Oil – Medium Efficiency | 19.7 | 36.4 | 35.8 | 34.3 | 33.7 | |
| Heating Oil – High Efficiency | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Natural Gas – Normal Efficiency | 213.6 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Natural Gas – Medium Efficiency | 162.3 | 186.7 | 172.9 | 159.0 | 145.4 | |
| Natural Gas – High Efficiency | 91.0 | 243.2 | 256.5 | 269.4 | 283.2 | |
| Electric | 236.1 | 363.1 | 369.1 | 374.4 | 379.8 | |
| Heat Pump | 24.8 | 45.0 | 46.3 | 47.5 | 48.8 | |
| Other1 | 16.3 | 8.9 | 8.7 | 8.6 | 8.4 | |
| Wood | 0.9 | 1.2 | 1.2 | 1.2 | 1.2 | |
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 | 2.4 | 0.1 | 0.1 | 0.1 | 0.0 | |
| Heating Oil – Medium Efficiency | 2.2 | 3.6 | 3.5 | 3.3 | 3.2 | |
| Heating Oil – High Efficiency | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Natural Gas – Normal Efficiency | 24.1 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Natural Gas – Medium Efficiency | 18.3 | 18.3 | 16.8 | 15.4 | 13.9 | |
| Natural Gas – High Efficiency | 10.3 | 23.8 | 24.9 | 26.0 | 27.2 | |
| Electric | 26.6 | 35.6 | 35.9 | 36.2 | 36.4 | |
| Heat Pump | 2.8 | 4.4 | 4.5 | 4.6 | 4.7 | |
| Other1 | 1.8 | 0.9 | 0.8 | 0.8 | 0.8 | |
| Wood | 0.1 | 0.1 | 0.1 | 0.1 | 0.1 | |
Dual Systems | ||||||
| Wood/Electric | 6.8 | 7.8 | 7.8 | 7.9 | 8.0 | |
| Wood/Heating Oil | 2.4 | 2.7 | 2.8 | 2.8 | 2.8 | |
| Natural Gas/Electric | 1.4 | 1.8 | 1.8 | 1.8 | 1.9 | |
| Heating Oil/Electric | 0.7 | 0.9 | 1.0 | 1.0 | 1.0 | |