Warm air will find any nook and cranny to to leave your home feeling cold. Cold air is sucked in to replace the warmer air, causing draughts.
Shutting doors and closing windows may not be enough as any gaps in the frames allow warm air to escape – and that costs money.
The letter box or bottom of the door can often an escape route for hot air. But by simply adding a draught excluder – or even a rolled up towel – the draughts can be blocked.