Calculation Example: Modern lamps save a great deal of energy
Lighting comfort means light for a sense of wellbeing – especially in the the home. And that does not need to be expensive or bad for the environment. On the contrary, the energy required for home lighting can be cut by about half – provided that energy-efficient lamps such as modern IRC halogen and energy-saving lamps are used.
Cost comparison: the savings in figures
| Energy-saving lamp1) | Incandescent lamp |
Wattage | 11 Watt (W) | 60 Watt (W) |
Operating time | 8.000 hours | 8.000 hours |
Life | 8.000 hours | 1.000 hours |
Power consumption over | 88 kWh | 480 kWh |
Cost of electricity at | 15.84 euros | 86.40 euros |
+ Price of lamp(s) | 12.19 euros | 7.12 euros3) |
Total cost | 28.03 euros | 93.52 euros3) |
Saving | 65.49 euros |
|
1) The calculation applies analogously to compact fluorescent lamps with pin base.
2) kWh = kilowatt hour; 3) Price of 12 incandescent lamps at 0.89 euros each
Calculation example: 3-room apartment
| Number of | before | after | saved4) |
Kitchen | 2x | 75 W | 15 W | 172.80 euros |
Bathroom | 1x | 75 W | 15 W | 86.40 euros |
Hall | 2x | 60 W | 11 W | 141.12 euros |
Living room | 3x | 60 W | 11 W | 211.68 euros |
Children's room | 2x | 75 W | 15 W | 172.80 euros |
Bedroom | 3x | 60 W | 11 W | 211.68 euros |
Total amount saved: |
|
|
| 996.48 euros |
4) Cost of electricity saved after incandescent lamps are replaced with energy-saving lamps, calculated on the basis of 8,000 operating hours at an average electricity price of 0.18 euro/kWh.
The maths
1 kilowatt hour (kWh) = kilowatt (kW) x hours (h);
1 kW = 1,000 watts (W); electricity price assumed: 0.18 euros per kWh;
Operating time: 8,000 hours
Cost of electricity for 60 W incandescent lamp
0.06 kW x 8,000 h x 0.18 euro/kWh = 86.40 euros
Cost of electricity for 11 W energy-saving lamp
0.011 kW x 8,000 h x 0.18 Euro/kWh = 15.84 Euro
Saving: 70.56 euros
