Reputable LED fitting manufacturers will provide a five or 10 year warranty for their industrial products, it should be possible to achieve payback at least once within the warranty period from the combination of energy and maintenance savings, or even multiple returns on investment in the lifetime of the LED luminaires.

 

Case study 1: 1.1 year payback from savings on energy alone

Warehouse lit by 150W Dialight LED high bays in foreground and 400W HPS at the back

In this case, a 20,000 sqm distribution warehouse had a mix of 136x250W and 100x400W high pressure sodium (HPS) high bays actually drawing 280W and 430W respectively. Due to the long re-strike time, the fixtures were in use 24/7 and the quality of light was poor, which made it hard for workers to easily identify labels when picking stock.

 

The engineering manager was looking for alternative lighting that would not only save energy but improve the light quality. He replaced each row of five HPS high bays with a row of three 150W LED high bays and more than achieved his objectives. As a result, more than 544,000kWh was saved annually – a reduction of 76%. The Watts/sqm came down from 4.05 to 0.95 and annual CO2 emissions were reduced by 296t. The distribution warehouse saw a vast improvement in light quality and the LEDs’ instant-on ability allowed switching off as needed with no more re-strike delays.

 

As a heavy user, annual energy savings in this UK facility were vast and resulted in fast payback while additional savings were also made from avoidance of carbon tax, reduced lamp maintenance and by claiming Enhanced Capital Allowance. When dimming and proximity sensors are also introduced, even greater savings will be possible.

 

Case study: 1.2 years payback from savings including maintenance

Bulk store lit by 13 HPS and 8 Dialight LED high bays

In another situation, a dockside bulk storage facility had 13x400W HPS that were drawing 440W each. The heat generated by the HPS was burning cargo dust onto the polycarbonate lenses and impairing their performance. Maintenance could only be carried out when the store was empty and involved the cost of two men for one week, hire of a cherry picker, 13 replacement polycarbonate lenses and 4-5 lamp changes that amounted in total to £2297 annually. The energy manager decided to switch to LED lighting as an energy efficient solution that would greatly reduce the associated maintenance costs.

 

As the lights are only in use 8h a day, 5 days a week and 50 weeks per year, their replacement with 8x172W LED high bays delivers annual energy savings of 16% of the cost of the LED lighting. At this low usage level, however, the 5-year warranted LED high bays can be expected to last for 10 years or more, effectively eliminating the burden of maintenance costs. The LED fittings will continue to pay for themselves in combined energy and maintenance savings throughout their extended lifetime.

 

It’s clear that in cases of relatively low use of lighting, the financial savings made possible by improving energy efficiency are only a part of the bigger picture. Maintenance reduction can often eclipse energy efficiency to increase the financial savings while also reducing disruption to the business, so it’s worth exploring this aspect fully when trying to calculate your likely payback period.