Originally Posted by mikeg205
Some have hung light in their dog house... but you need about 24 hours at 24 degrees iirc to worry about it...
Bear in mind that while wind temp doesn't lower metal temperature, it does speed temperature loss.
This is the fact that "wind chill" will never reduce the temps of surfaces below ambient, it will just get them to ambient FAST.
Where this is important; if it is windy and below freezing, that wind will increase the probability of a hard freeze in the engine. A bulb can warm the compartment, so long as there isn't a bunch of air flow, so the bulb making heat in an insulated engine box, with the tarp on securely then that is better than untarped.
If you park it in a lean to or a garage, or even behind a row of trees blocking the wind, that will be better.
My favorite are magnetic block heaters, gets the heat where you need it (the block) not just randomly in the bilge.