A number of years ago, I'd bought a house in Lisburn, but hadn't quite moved in yet. Snow was forecast, and there seemed no point going up Prince William Road and negotiating the Knockmore Road to get back to the house too soon, so I made sure the thermostat in the hall was turned up and locked up.
The snow fell, and two days later I drove up to see if any pipes had frozen. The driveway was unblemished, with three or more inches of untouched snow covering it.
It was then I noticed something strange. There was a border, a moat, around the house with no snow. Over half a foot wide. Yet it was only around my semi-detached, and didn't extend to Deborah next door.
I put the key in the lock, opened the door, and took a step inside. Stepped back pretty quick as I hit a wall of hot air like a furnace.
It was a couple of minutes before enough icy cold air had got in the front door to make it comfortable to go indoors. Even the outside brickwork of the house was warm to touch!
Turned out that as I'd left the house before the snow, I'd turned the central heating on to the "constant" setting rather than "automatic", so the boiler had been pumping hot water around the radiators for 48 hours solid.
Certainly dried the house out - and kept the neighbour warm too. Just doing my part for global warming!