Would it be rude....?

My kids, my fiancé, and myself are currently staying with my parents due to a series of unfortunate events (lol) that effected us financially. They are letting us stay for free and I do most of the cleaning and help them with their business. The problem is now that it’s getting cold out their house is FREEZING! They keep the heat on 64 and the house is older and has a TON of windows and doors that I feel aren’t insulated well. Me and my 9 month old are sick and I feel that it’s because of how cold the house is. I want to talk to them about keeping it warmer in the house at least for the baby but I don’t want to impose because I’m not in a situation to chip in on the energy bill.

Oh, and I do keep my baby in fleece jammies all day to keep her warm. We even purchased a small space heater for the bedroom to keep us warm at night. But despite this we’re still freezing and sick.