I wonder what a nice indoor temperature was back in the day? Say 400 years ago, maybe northern Germany. My place is currently 49° at the thermostat, warmer by the stove, cooler in my bedroom. It's not so bad. I wouldn't call it luxurious, but it isn't misery, and it has some benefits. I kind of like shivering under the blanket til my body raises the temperature, and the cool air is nice on my face.
I'd guess peasants probably had warmer accommodations due to the small size of their houses. A big manor house or castle would be a real bastard to heat well when the temps are down, and it's all open hearth, so your heat is going up the chimney.
So, all the guests arrive at the castle for the yule celebration. What does it feel like when you go inside? Pretty nice, or you can barely hold the silverware cause your hands are so cold?
I go into someone's house now, it's like opening an oven door. Probably what working a blast furnace at the steelmill was like :^D I used to hate that when malls were a thing. My hands would feel like they were swollen from walking around in the heat. Everybody's got their winter crap on, so lets jack up the temps so it's miserable inside, and you have a choice of leaving your stuff on for extra misery, or carry it for extra hassle. And hey! Maybe they'll lose their jacket somewhere and have to buy a new one! That'll certainly pay for the energy expense.