BE99 pilot reported electrical burning smell was determined after landing to be engine inlet electric boot had burnt.

Narrative

While IMC descending toward ZZZ; about 30 nm out from ZZZ; the pilot started smelling an electrical burning smell in the aircraft. The pilot turned off the window heat but the smell got worse. The pilot told ATC about the electrical burning smell and advised ATC. The weather at ZZZ was about 1 1/2 miles and snowing. The pilot shut off some other nonessential electrics like the panel lights. The pilot never saw any flames. None of the circuit breakers had popped out or felt hot. The pilot put his O2 mask on. The pilot kept trouble shooting and then shut off the bleeds. When the bleeds were shut off the smell began to dissipate. The pilot landed at ZZZ without incident.During post flight the right engine cowling was opened and the electrical burning smell was strong at this point. After looking in the engine compartment and then at the cowling; it was found that about 3/4th of the right side engine inlet electric boot appeared to be burnt through exposing the copper wire. The pilot thinks that the electrical burning smell was traveling from the engine inlet; through the engine compressor; and then through the bleed air system to get into the cabin.