for me.. I'm trying to find a projector that will "withstand the elements" even if I put it in some kind of enclosure, it's still going to have to put up with the cold..
That is where you are very lucky in terms of insulation material costs compared to we brits!
if you grab some foil faced insulation board, & make a small box to go round the unit heat will pretty much look after itself, ..tape up the sides with insulation foil tape so it's as air tight as possible, then where the vent is have a vent, but stick a scrap of tyvek there to keep moisture out, the insulation will be something you can monitor with a sensor / stick your hand into & gauge a few nights before by running it outside to be sure of any adjustments.
by insulating it properly it should totally look after itself heat-wise without a problem (but it does need an air vent, even if it's an led bulb).
Don't worry about it getting cold, worry about it getting too warm, thats the reality, a test run should cure that easily as air flow is adjustable.