A simple method to compare cost and saving.
Learning Track · Module 4: Energy and carbon · Step 30 of 101
Showing content for Europe. Change the region at the top of the page.
New: 70 W LED
Saved: 100 W × 4,200 h = 420 kWh per year
Europe: 420 kWh × €0.20 = €84 per light per year. At €300 installed: payback ≈ 3.6 years Middle East: 420 kWh × AED 0.40 = AED 168 per light per year. At AED 1,100 installed: payback ≈ 6.5 years South Asia: 420 kWh × ₹8 = ₹3,360 per light per year. At ₹7,000 installed: payback ≈ 2.1 years USA: 420 kWh × $0.13 = $55 per light per year. At $350 installed: payback ≈ 6.4 years
Add the maintenance saving (sodium lamps need a change every 3 to 4 years) and dimming, which often adds 20% to 40%. Middle East: Low or subsidised tariffs make energy-only payback long. Include maintenance and carbon in the case. USA: Check utility rebates. They often require DLC-listed products. Use your own figures in the cost of ownership tool.
Warning
Old mercury, sodium, and metal halide lamps contain mercury. Dispose of them as hazardous waste through a licensed collector.
Related across the playbook: Planned replacement: Spot or group replacement.
Sources
- Minamata Convention on Mercury
- Directive 2012/19/EU (WEEE)
- E-Waste (Management) Rules, 2022 (India)
Changes: 30 October 2026: First publication: guides for Europe, the Middle East, South Asia, and the USA; failure library; tender clause library; comparisons; tools; downloads. See the changelog. Found a mistake? Report it.