With no filament to break or burn out, LEDs can last 40,000 hours, approximately 20 years of regular use, compared with just two years for halogen bulbs. LEDs are also extremely efficient, sipping 1 to 11 watts of power versus 20 to 60 watts for halogens. That means lower installation costs due to smaller transformers and cables, lower operating costs, and reduced maintenance, for up to a 50-percent savings over halogen systems in the course of 15 years.
But LEDs have their drawbacks, chiefly their high initial cost—about $40 per bulb, compared with about $5 for a similar halogen. Also, many LEDs have a cold blue light with a color temperature around 6,000 K (kelvins). Look instead for a warm-color temperature, about 3,000 K. And don't forget to look at light output, in lumens, to make sure you're getting enough brightness. LED performance is improving, but it still lags behind that of halogens. Dismal output is the biggest knock against solar-powered fixtures, which all use LEDs. They might have enough glow to define a garden edge but not to light up your house.