| 2000 | 2018 | 2019 | 2020 | 2021 | ||
|---|---|---|---|---|---|---|
| Total Single Detached Heating System Stock (thousands) | 734.0 | 1,038.5 | 1,047.7 | 1,056.7 | 1,066.5 | |
Heating System Stock by Heating System Type (thousands) | ||||||
| Heating Oil – Normal Efficiency | 3.6 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Heating Oil – Medium Efficiency | 1.3 | 2.3 | 2.2 | 2.2 | 2.1 | |
| Heating Oil – High Efficiency | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Natural Gas – Normal Efficiency | 328.4 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Natural Gas – Medium Efficiency | 320.9 | 413.6 | 388.1 | 362.1 | 335.2 | |
| Natural Gas – High Efficiency | 37.5 | 458.2 | 487.7 | 517.3 | 548.7 | |
| Electric | 11.4 | 112.4 | 116.7 | 121.0 | 125.2 | |
| Heat Pump | 13.5 | 33.5 | 34.5 | 35.5 | 36.7 | |
| Other1 | 10.6 | 8.0 | 7.8 | 7.7 | 7.6 | |
| Wood | 0.5 | 0.0 | 0.0 | 0.0 | 0.0 | |
Dual Systems | ||||||
| Wood/Electric | 0.9 | 1.5 | 1.5 | 1.5 | 1.6 | |
| Wood/Heating Oil | 3.1 | 4.9 | 5.0 | 5.1 | 5.2 | |
| Natural Gas/Electric | 2.1 | 4.0 | 4.0 | 4.1 | 4.2 | |
| Heating Oil/Electric | 0.1 | 0.1 | 0.1 | 0.1 | 0.1 | |
Shares (%) | ||||||
| Heating Oil – Normal Efficiency | 0.5 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Heating Oil – Medium Efficiency | 0.2 | 0.2 | 0.2 | 0.2 | 0.2 | |
| Heating Oil – High Efficiency | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Natural Gas – Normal Efficiency | 44.7 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Natural Gas – Medium Efficiency | 43.7 | 39.8 | 37.0 | 34.3 | 31.4 | |
| Natural Gas – High Efficiency | 5.1 | 44.1 | 46.5 | 49.0 | 51.5 | |
| Electric | 1.6 | 10.8 | 11.1 | 11.5 | 11.7 | |
| Heat Pump | 1.8 | 3.2 | 3.3 | 3.4 | 3.4 | |
| Other1 | 1.4 | 0.8 | 0.7 | 0.7 | 0.7 | |
| Wood | 0.1 | 0.0 | 0.0 | 0.0 | 0.0 | |
Dual Systems | ||||||
| Wood/Electric | 0.1 | 0.1 | 0.1 | 0.1 | 0.1 | |
| Wood/Heating Oil | 0.4 | 0.5 | 0.5 | 0.5 | 0.5 | |
| Natural Gas/Electric | 0.3 | 0.4 | 0.4 | 0.4 | 0.4 | |
| Heating Oil/Electric | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | |