Stone floor

Broomstick

My teenage sons and I moved to a new house (well insulated, doubled glazed, well-fitting non-draughty doors, central heated with combi boiler) earlier this year and haven't been here through the winter before. We managed to keep the heating off until the temperature dropped a week ago. We wear slippers, jumpers, socks, sometimes coats indoors etc but the downstairs of the house is feeling freezing all the time even with the heating switched up to 20 all day :eek:(can't afford to keep that going). Problem is that it has a stone floor throughout - porch, sitting room and kitchen/diner (will be a blessing in the heat of the summer!) and the cold stone just seems to guzzle up what heat there is. We have a large latex backed IKEA rug in the sitting room but I can't afford to get rugs for the rest of the downstairs. I don't want to carpet anyway because we are in a flood zone and may need to clear the ground floor in a hurry. Has anyone any ideas of what we can do to the floor (pref. free) to solve the freezing downstairs. I don't want to spend the next few months living upstairs full time unless absolutely necessary. Upstairs is staying nice and warm on low heating so we will move there for Christmas if we have to. I'd just like to be able to use downstairs more comfortably.

Many thanks
B