Tis the Season to Shut the Door!

I feel the cold.  Bear certainly doesn't.  He has a habit of shedding clothing as he wanders around and would happily spend most of his time in his vest.  The only exception is if he is getting out of bed, as the last few mornings bear has had to fight to get out of his pit instead of his usual eruption into the day.  The feeling of cold doesn't last long, though, and he is soon spraggled across the settee and shedding socks.  DH doesn't feel the cold as much, either.  He hangs around in his shirt, perfectly relaxed while I am shivering under a blanket.

I really feel the cold.  I really, really feel the cold.  I always wear slippers, sweaters, t-shirts and cardigans.  I snuggle into blankets and wear gloves and a hat when I go out.  I need the heating on.

I hate paying for heating.

I keep 'air exchange' in mind.  To function properly and safely we need a certain about of fresh air.  That means that I have the windows open at least once a day on each floor, even for a short time, as I race around trying to stay as warm as possible and flinching.  I wouldn't mind, our house is very warm and we don't really suffer as much as most.  However as I wince at the cold and the heating is so expensive I keep to the checklist.

Lined curtains at the double glazed windows, finally!  At the moment they are bunched up on the windowsill but I will, eventually, get my sewing machine working and shorten them so they don't cover the radiators.  If my sewing machine isn't sorted out soon I am using fabric glue.
Draft excluders
Thermostat on the central heating set to 19 degrees and on a restricted timer.  The rest of the time only heating the rooms we are in.
Low cost halogen heaters.
Slippers, socks, t-shirts under sweaters, blankets to snuggle in.
Hot drinks
Keeping moving, keeping ironing.
Lighting candles - it always surprises me how much extra warmth they can add over an evening as well as a lovely snuggly glow.
Leave the oven door open after cooking
Shut the internal doors to keep the warm in - I'm working on this.

I am fine with coming or going but I am not fine with sitting in a draught.  Bear is indifferent.  So this weekend I will be once again shouting 'Door!' and he will once again be shouting 'Darn!' and the doors will be slammed shut.  And again.  And again.  I will disappear downstairs for thirty minutes and will come up to find the heat from the heater in the study wafting happily up the stairs through the open door to the study, the door to the stairs and probably the door to the icy porch.

How do you make a nearly eight year old keep a door shut?  I could try threats but bear would snigger at me.  I could try bribery but I am being extremely tightfisted on the run up to Christmas, not just because of expense but also so he gets to appreciate the gifts.  Repetition isn't working.  He just good-naturedly chuckles and dashes back to slam the door - again.

All suggestions welcome.