Economics: compare purchase, operation and lifecycle costs
Assess investment with realistic assumptions rather than purchase prices alone.
Purchase price is only part of lighting cost. Investment may include planning, installation, controls, access equipment and disposal. Operation brings electricity, cleaning, inspection and replacement costs. For inaccessible luminaires, access labour can cost more than an individual spare part.
A fair comparison uses the same assessment period and price basis. Both alternatives must provide suitable lighting. State operating hours, electricity prices, control effects, maintenance and any confirmed grant separately. A second scenario with more conservative assumptions helps assess uncertainty.
Simple payback shows when accumulated savings offset investment. It gives limited treatment to later costs and the time value of money. Longer assessments should also consider total costs, replacement investment and, where appropriate, discounting. A short calculated payback does not replace technical assessment or a reliable project estimate.
What to clarify for your project
- Include all investment components and operating costs.
- Calculate at least one conservative usage scenario.
- State assumptions, support and replacements transparently.
Remember: An economical solution combines suitable light with appropriate costs over its use.