Need help with a moving situation please.?

Put on a sweater and stay put.

It's going to cost you $5,000 a year more to keep living in the 3-bed house. Unless you desperately need the space, i.e people you live with like your children or whatever need the rooms to sleep in, then you're throwing $5,000 away on space you don't need so for me the heating wouldn't even come into it. If you need to the space to store stuff or as a guest room then turn the radiators off in them because you're wasting energy by heating them- maybe you could tell the landlady you've done this in the hope that she'll turn the heating up a bit. I wouldn't let the ambient temperature of a place decide where I was going to live though because there are so many things you can do, that are free, to keep yourself warm. You should really only have the heating on if you're still cold when you're dressed warmly- given the state of the environment it's not right to have it on if you're sat there in a t-shirt, you know?