| 2000 | 2018 | 2019 | 2020 | 2021 | ||
|---|---|---|---|---|---|---|
| Total Single Detached Heating System Stock (thousands) | 16.9 | 22.7 | 23.2 | 23.7 | 24.3 | |
Heating System Stock by Heating System Type (thousands) | ||||||
| Heating Oil – Normal Efficiency | 6.4 | 1.0 | 0.6 | 1.1 | 0.4 | |
| Heating Oil – Medium Efficiency | 4.8 | 13.4 | 14.2 | 14.1 | 15.0 | |
| Heating Oil – High Efficiency | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Natural Gas – Normal Efficiency | 0.9 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Natural Gas – Medium Efficiency | 1.1 | 1.6 | 1.5 | 1.4 | 1.3 | |
| Natural Gas – High Efficiency | 0.7 | 2.8 | 3.0 | 3.2 | 3.5 | |
| Electric | 0.6 | 0.6 | 0.6 | 0.6 | 0.6 | |
| Heat Pump | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Other1 | 1.7 | 2.0 | 2.1 | 2.1 | 2.2 | |
| Wood | 0.9 | 1.2 | 1.2 | 1.2 | 1.2 | |
Dual Systems | ||||||
| Wood/Electric | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Wood/Heating Oil | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Natural Gas/Electric | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Heating Oil/Electric | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | |
Shares (%) | ||||||
| Heating Oil – Normal Efficiency | 37.6 | 4.6 | 2.7 | 4.6 | 1.7 | |
| Heating Oil – Medium Efficiency | 28.3 | 59.3 | 61.2 | 59.3 | 62.0 | |
| Heating Oil – High Efficiency | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Natural Gas – Normal Efficiency | 5.1 | 0.2 | 0.1 | 0.1 | 0.1 | |
| Natural Gas – Medium Efficiency | 6.6 | 6.9 | 6.4 | 5.8 | 5.3 | |
| Natural Gas – High Efficiency | 4.0 | 12.3 | 12.9 | 13.4 | 14.3 | |
| Electric | 3.3 | 2.6 | 2.6 | 2.6 | 2.6 | |
| Heat Pump | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Other1 | 9.8 | 9.0 | 9.0 | 9.0 | 8.9 | |
| Wood | 5.3 | 5.1 | 5.1 | 5.1 | 5.1 | |
Dual Systems | ||||||
| Wood/Electric | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Wood/Heating Oil | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Natural Gas/Electric | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Heating Oil/Electric | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | |