Of course reduce the area and the temperature to retain heat. I also believe a closed room acts like an insulating “dead-air” space.
Many people forget how to regulate the temperatures in their homes by some simple techniques, Drapery being the first thing that comes to mind. Open drapes on south facing windows to allow solar heat, then close the drapes during the night to conserve it.
Recently, I’ve read that houses built to conserve heat don’t have North facing windows. I recalled that I hadn’t removed the storm windows from that side of my house for twenty years. I’m considering somewhat permanently increasing the weather proofing of those windows. I also seal off the North side rooms during the winter months.
I noticed the “tip” was courtesy Liberty Mutual Insurance. I sort of imagine their logo as a pirate flag.
Drapes/shades/blinds can definitely make a difference. I’ve often fantasized about an automated photosensing shade system that would open blinds when the sun strikes the window and close them when shady. Unless you work from home, it’s hard to get this accomplished manually…
Most modern homes have have only 1, or maybe 2, heating zones. So while rooms may be unused, they’re not unheated; if ‘the heat is on,’ simply closing off rooms saves no heat.
To be effective, homeowner would need to first expend some effort to drape a blankets over radiators – or some such. And then, once the unused portion got cold, there would likely be cold draughts blowing around through interior doors, The Horror.
Leif, your home isn’t even “modern” and it has like 32 heating zones. I’ve seen your wall of valves! Anyway, even in my prior ancient, “one-zone”, oil-fired, steam-heated house, the radiators in unused rooms could be shut off and the door closed…
Hope your wood stove(s) is on and your furnace is off!