Here is the math supporting the economic viability of the retrofit:

Halogen VS LED energy savings per bulb is 18W. 18W multiplied by 8,760 hours per year = 157,680 Watt-Hours. Divide by 1,000 to get 157.7 kWh. In NYC, average energy rates are about $0.18 per kWh, so the annual energy cost savings of each light bulb is $28.39. Considering the LED GBF light bulbs cost $30.00, we can be assured of a one year simple payback. If we add in maintenance and materials cost savings, the math gets even better. Each halogen GBF costs about $10 and has an average rated life of 2,000 hours. The LED GBF has a three year manufacturer's warranty, which equates to 26,280 hours of warrantied service life. Over this period, materials costs for replacement halogen GBF light bulbs would run over $130, (thirteen GBF bulbs x $10 per light bulb). So the total economic benefit of the three year warrantied life of the LED is over $185, or over $61 per light bulb per year. 

The elevator cab pictured below has six light bulbs, so the owner of this property has just increased his net cash flow by $366 annually. Assuming the property is valued at a modest 10 percent capitalization rate, the value of the property increased by $3,660 per elevator cab. 

Of course, none of this matters if the elevator's lighting is no longer acceptable. Happily, that is not the case. The lighting looks great, and a major heat source uncomfortably close to the heads of elevator users has been permanently removed. 

Here are the before and after photos: