I have dozens of Cree-brand LED bulbs in my home (they're the uber-cheap brand Home Depot carries, yet always very favorably reviewed). Their packaging carries no warnings against use in totally enclosed fixtures, and I have several in such fixtures in bathrooms. They also come with a 10-year full replacement warranty. Some are now about two years old, and none of their bulbs have failed or even become too hot to touch.
I have a feeling this guy's overstating the problem. Perhaps because he's in the business of patenting thermal protection designs for bulb manufacturers.
I have a feeling this guy's overstating the problem. Perhaps because he's in the business of patenting thermal protection designs for bulb manufacturers.