Well the good news is there isn't a catch, the conversion to LED is worth your time. The savings are real, the quality of light is that good, and the reduction in maintenance is as good as what you have been told. But lets back it up with a few facts.
1. Reduction in Energy:For this calculation, we are going to talk about our 400W LED High Mast light that operates at 130 lumens/watt. This light is more than enough to replace a 1000W Metal Halide or High Pressure Sodium bulb. The LED Light consumes 400W, the old light consumes a total of 1150 watts when you include ballast draw. That represents a 66% savings per light, or 750 actual watts saved per light. That's almost $400 a year saved per light, assuming the lights run 12 hours a night and 365 days a year at .12 kw.h charge. That's real money, and considering some high mast poles have 12 lights, that's almost a savings of $5000 per year.
2. Reduction in Maintenance CostsThe life of LED is measured in 2 ways, the life of the LED (L70) and the life of the entire fixture. L70 is a measurement of lumen depreciation - how long in hours before the light has lost 30% of its initial brightness. With LED, the number should start at 50,000 hours. Some have made claims of 200,000 hours, but no one will be around to determine if that is in fact a reality. But 50,000 hours represents 12 years of not changing bulbs. And in a high mast light mounted 120 feet in the air, this is a good thing
The other measurement is how long will the entire fixture work. In other words, how long before one of the components fail. No one knows for sure, LEDs are electronics and sometimes electronics fails. But it is not unreasonable to expect these electronics parts to last at least 50,000 hours or more. So once again, this puts you into the 12+ years of zero maintenance.
3. Better Quality of LightThe quality of light is a measurement of Color Rendering Index, or CRI. This scale of CRI is 0 to 100, 100 being daylight. So the closer a bulbs is measured to 100 CRI, the more it represents sun light.
LEDs have great CRI, typically starting at around 70 and going into the 90's. A CRI 90 bulb would be something you would want to use in a retail store or car dealership, where presentation is everything. In the world of high height flood lighting, 70+ CRI is just fine. And when you compare that to the CRI of High Pressure Sodium (around 30), the improvement is incredible