| Lumen estimates | ||||||||||
| Type of lamp | Nominal wattage |
Beam angel | Luminous intensity, cd |
Transformer losses ~5 % |
kWh usage 1500 h annual operation |
Stand-by losses (3 W x 7260 h), kWh |
Total annual energy use, kWh |
Annual energy use with advanced transformer*, kWh |
Total lumen flux (emitted), lm |
Emitted lumen per watt, lm/W |
| 230V GZ10 | 50W | 25° | 1250 | n/a | 75 | none | 75 | 75 | ~200 | ~4 |
| 12V standard | 50W | 25° | 2700 | 2,5 W | 79 | 22 | 101 | 80 | ~500 | ~10 |
| 12V IRC lamp | 50W | 24° | 5700 | 2,5 W | 79 | 22 | 101 | 80 | ~900 | ~17 |
| 12V IRC lamp | 35W | 24° | 4400 | 1,5 W | 55 | 22 | 77 | 58 | ~700 | ~19 |
| 12V IRC "wish lamp"# | 20W | 24° | 2500 | 1 W | 32 | 22 | 54 | 35 | ~400 | ~19 |
Lumen data are not published by manufacturers. The lumen output from these reflector lamps takes reflector losses into account and has been calculated based on catalogue data on luminous intensity and light distribution diagrams. Lumen data are thus rough estimates. The new mains-voltage halogen lamps come in a 50-W narrow-beam and a broad-beam version. The table only shows narrow-beam lamps, but the relation between the various broad-beam lamps is roughly the same. The energy estimates donšt take production energy for lamps and transformers into account.
*The advanced transformer is assumed to have 1W operation losses and stand-by losses of 0,5W (3,5 kWh/year).
# This lamp is not available on the market but has been mentioned by manufacturers. The data on luminous intensity represent an estimate based on data of the 35- and 50-W infrared-coated (IRC) lamps.