| 2000 | 2018 | 2019 | 2020 | 2021 | ||
|---|---|---|---|---|---|---|
| Total Single Attached Heating System Stock (thousands) | 628.1 | 890.6 | 903.9 | 919.1 | 934.3 | |
Heating System Stock by Heating System Type (thousands) | ||||||
| Heating Oil – Normal Efficiency | 31.7 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Heating Oil – Medium Efficiency | 29.3 | 28.7 | 26.4 | 23.9 | 21.2 | |
| Heating Oil – High Efficiency | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Natural Gas – Normal Efficiency | 189.7 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Natural Gas – Medium Efficiency | 127.0 | 136.2 | 125.3 | 114.7 | 104.4 | |
| Natural Gas – High Efficiency | 103.0 | 471.9 | 492.5 | 514.0 | 535.2 | |
| Electric | 105.4 | 172.6 | 175.8 | 179.5 | 183.2 | |
| Heat Pump | 16.0 | 36.8 | 38.2 | 39.7 | 41.2 | |
| Other1 | 8.0 | 28.4 | 29.9 | 31.6 | 33.5 | |
| Wood | 13.4 | 9.1 | 8.8 | 8.5 | 8.2 | |
Dual Systems | ||||||
| Wood/Electric | 1.2 | 1.6 | 1.6 | 1.7 | 1.7 | |
| Wood/Heating Oil | 1.3 | 1.6 | 1.7 | 1.7 | 1.7 | |
| Natural Gas/Electric | 1.6 | 2.8 | 2.9 | 2.9 | 3.0 | |
| Heating Oil/Electric | 0.5 | 0.9 | 0.9 | 0.9 | 0.9 | |
Shares (%) | ||||||
| Heating Oil – Normal Efficiency | 5.0 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Heating Oil – Medium Efficiency | 4.7 | 3.2 | 2.9 | 2.6 | 2.3 | |
| Heating Oil – High Efficiency | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Natural Gas – Normal Efficiency | 30.2 | 0.0 | 0.0 | 0.0 | 0.0 | |
| Natural Gas – Medium Efficiency | 20.2 | 15.3 | 13.9 | 12.5 | 11.2 | |
| Natural Gas – High Efficiency | 16.4 | 53.0 | 54.5 | 55.9 | 57.3 | |
| Electric | 16.8 | 19.4 | 19.5 | 19.5 | 19.6 | |
| Heat Pump | 2.5 | 4.1 | 4.2 | 4.3 | 4.4 | |
| Other1 | 1.3 | 3.2 | 3.3 | 3.4 | 3.6 | |
| Wood | 2.1 | 1.0 | 1.0 | 0.9 | 0.9 | |
Dual Systems | ||||||
| Wood/Electric | 0.2 | 0.2 | 0.2 | 0.2 | 0.2 | |
| Wood/Heating Oil | 0.2 | 0.2 | 0.2 | 0.2 | 0.2 | |
| Natural Gas/Electric | 0.3 | 0.3 | 0.3 | 0.3 | 0.3 | |
| Heating Oil/Electric | 0.1 | 0.1 | 0.1 | 0.1 | 0.1 | |