Cold Air Kit

When installing a cold air kit, I understand that it's best to mount the air filter outside of the engine compartment, but with the air duct still being in the engine compartment wouldn't it be a good idea to insulate this as it's exposed to the heat of the engine compartment? Seems to me that even though the filter would be picking up cooler air that it would be almost as hot as if the filter was still under the hood.