| Value | Category |
|---|---|
| 1 | Central heating for building |
| 2 | Own domestic heating system using natural gas |
| 3 | Own domestic heating system using solid fuel |
| 4 | Own domestic heating system using liquid fuel |
| 5 | Stove using natural gas |
| 6 | Stove using solid fuel |
| 7 | Stove using liquid fuel |
| 8 | Other type of heating |
| 9 | NIU (not in universe) |