| Value | Category |
|---|---|
| 1 | SOLAR AIR HEATER |
| 2 | ELECTRICITY |
| 3 | PIPED NATURAL GAS |
| 4 | LIQUEFIED PETROLEUM GAS (LPG) / COOKING GAS |
| 5 | BIOGAS |
| 6 | ALCOHOL / ETHANOL |
| 7 | GASOLINE / DIESEL |
| 8 | KEROSENE / PARAFFIN |
| 9 | COAL / LIGNITE |
| 10 | CHARCOAL |
| 11 | WOOD |
| 12 | CROP RESIDUE / GRASS / STRAW / SHRUBS |
| 13 | ANIMAL DUNG / WASTE |
| 14 | PROCESSED BIOMASS (PELLETS) OR WOODCHIPS |
| 15 | GARBAGE / PLASTIC |
| 16 | SAWDUST |
| 96 | OTHER |
| 99 | NO RESPONSE |
| Sysmiss |