Hi , can anyone tell me is it better to leave the van on hu while at home and to leave the boiler and heating on when the weather turns a bit chilly like last night, not drained the boiler yet as will probably use in the next couple of weeks or should you drain everything down and refill before you use it, also should i leave the window blinds closed all the time ? have heard it's best not to whats the general opinion on everything, as still a newbie (only just on the upward climb of learning) thanks.