Short answer: No.
Longer answer: No, they do not.
Joking aside, based on semiconductor technology rather than heating a filament like an incandescent bulb, LED bulbs and light strings do not heat up under operation.
See How do LED Christmas lights make light? for a brief discussion of filament vs. semiconductor light production.
This makes them a great choice for the following applications:
- Live Christmas trees and real wreaths
- Stuffed in bottles and containers (especially LED craft lights that only have a single male plug)
- Wrapping trees
- Frankly, everywhere. *smile*
And even though they don't heat up under operation, LED lights are still electrical devices and they deserve the same respect that any electrical appliance receives.
- Don't install them near cribs and where toddlers play and can get their hands on them.
- Don't install them in, on, or near water features.
- Do use them with an electrical surge protector
So, planning to put lights on a vintage armoire this Christmas or across a mid-century sideboard to light up this Friday night?
In any application where heat might be an issue, consider LED light strings first.
Then invite us to your party! We'll bring the pimento cheese dip.