Can you change conventional festoons to LED festoons? Definitely yes!
Festoons come in three sizes (measured from the tips of the ends of the bulbs): 31mm, 37mm and 42mm, although the 31mm units are much less common than the latter two sizes. Clearly it's always best to try to stay with the sizes you currently have installed but we have spoken to the occasional customer who has simply bent the electrical contacts in or out depending on which way they have incorrectly guessed the size of their own bulbs. this isn't something we'd recommend!
The 37mm and 42mm LED Festoons are built up in rows of three LEDs, with each row of three LEDs being the equivalent to a 5 watt conventional festoon bulbs. Consequently, if you currently have a 10 watt festoon, then choose the LED version with 6 LED chips on the bulb.
The original festoon will consume 10 watts but the LED festoon will consume 1 watt but that is the object of the exercise!
As ever, if you're not sure of any aspect of changing over to LEDs don't hesitate to contact us.