They do seem to get hungrier when it's cold, probably burning off more energy trying to keep warm.
And if it's that cold out she might have just wanted in because it would have been slightly warmer.
In the same situation I would absolutely be the cat hotel XD
Our house was probably colder than our cat's room, downstairs. That is, up till this afternoon, when we installed a small stove in our bedroom.
You, a cat hotel?
Do you have cats yourself?
Back when I was at uni I decided to get a couple of kittens from a pet shop (we don't have shops that sell pets anymore, one of the pet supply shops does sometimes have animals from one of the rescues they have partnerships with). I decided to get a sibling pair as they were the last two and pretty much had to start saving up straight afterwards to get them desexed (there was one boy and one girl). At the age where they needed to get done, my stupid ex took the money that I had saved up for their operations and bought a freaking printer because "it was a really good deal!" and then I ended up with five cats with a year age gap between the parents and the babies x_x
Those ones are no longer with us and there are now another two in the house belonging to eldest.
Downstairs would have some insulation from the upstairs probably. Hope the stove helps! Are you just going into winter? Are you going to be able to get it warm enough?