| 2000 | 2018 | 2019 | 2020 | 2021 | ||
|---|---|---|---|---|---|---|
| Total Single Attached Heating System Stock (thousands) | 62.2 | 85.3 | 86.7 | 88.1 | 89.5 | |
Heating System Stock by Heating System Type (thousands) | ||||||
| Heating Oil – Normal Efficiency | 11.9 | 0.1 | 0.0 | 0.0 | 0.0 | |
| Heating Oil – Medium Efficiency | 13.1 | 17.5 | 17.3 | 16.9 | 16.7 | |
| Heating Oil – High Efficiency | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Natural Gas – Normal Efficiency | 0.1 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Natural Gas – Medium Efficiency | 0.3 | 0.3 | 0.2 | 0.2 | 0.2 | |
| Natural Gas – High Efficiency | 0.4 | 1.8 | 1.9 | 2.0 | 2.1 | |
| Electric | 23.8 | 52.2 | 53.6 | 55.1 | 56.4 | |
| Heat Pump | 1.3 | 3.3 | 3.5 | 3.6 | 3.8 | |
| Other1 | 0.7 | 1.3 | 1.3 | 1.3 | 1.4 | |
| Wood | 8.4 | 6.2 | 6.2 | 6.2 | 6.2 | |
Dual Systems | ||||||
| Wood/Electric | 1.0 | 1.2 | 1.2 | 1.2 | 1.2 | |
| Wood/Heating Oil | 0.7 | 0.7 | 0.8 | 0.8 | 0.8 | |
| Natural Gas/Electric | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Heating Oil/Electric | 0.4 | 0.7 | 0.7 | 0.7 | 0.7 | |
Shares (%) | ||||||
| Heating Oil – Normal Efficiency | 19.2 | 0.1 | 0.0 | 0.0 | 0.0 | |
| Heating Oil – Medium Efficiency | 21.1 | 20.5 | 19.9 | 19.2 | 18.7 | |
| 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 | 0.3 | 0.3 | 0.2 | 0.2 | |
| Natural Gas – High Efficiency | 0.6 | 2.1 | 2.2 | 2.3 | 2.4 | |
| Electric | 38.3 | 61.2 | 61.9 | 62.5 | 63.0 | |
| Heat Pump | 2.1 | 3.9 | 4.0 | 4.1 | 4.2 | |
| Other1 | 1.1 | 1.5 | 1.5 | 1.5 | 1.5 | |
| Wood | 13.6 | 7.3 | 7.1 | 7.0 | 6.9 | |
Dual Systems | ||||||
| Wood/Electric | 1.7 | 1.4 | 1.4 | 1.4 | 1.4 | |
| Wood/Heating Oil | 1.1 | 0.9 | 0.9 | 0.9 | 0.8 | |
| Natural Gas/Electric | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Heating Oil/Electric | 0.7 | 0.8 | 0.8 | 0.8 | 0.8 | |