| Value | Category | Cases | |
|---|---|---|---|
| 1 | Central heating system | 837 |
20.9%
|
| 2 | Electric heater | 19 |
0.5%
|
| 3 | Boiler | 88 |
2.2%
|
| 4 | Stove | 3056 |
76.4%
|