You need
. Uninsulated yurts (like mine) don't hold the heat at all. About like duck hunting when it's 10f, in a long sleeve shirt and a pair of jeans. Staying warm ain't gonna happen. You need insulation-- heavy clothes.
You can't expect to heat a side room if the main room won't hold the heat. If the yurt actually holds the heat-like in an insulated house for example- an adjacent room will eventually warm up a bit. To REALLY warm it up you need to duct in hot air, fan in hot air, or add a heater to that room.