Nah, I phone the heating from the pub as I get the last* round in and it runs for an hour with extra ducts running under the duvet, when we get back the boat is toasty and the bed is roasted, get in a warm bed and you stay that way all night without heating on.
As for the open fire/pub theory, we've been known to take a bag of logs along with us in winter.
* last may not really mean last.