It has been barely making it past 0C during the day round here for about the last two weeks. Today was especially cold as the central heating will not come on automatically when it is really cold ! Apparently this is a well known problem amongst condensing boilers and is a safety feature ! It is due to the condensate pipe possibly freezing when it is really cold ! We like to joke about it as it seems very silly that these boilers are promoted as so much more efficient than old ones but are no use when it gets really cold ! Once we realise that it hasn't come on because the indoor temperature is really icy then we have to go into the garage to turn it on manually. The problem with doing this is that by then the house is very cold and it takes a long time to warm up again, 4-5 hours usually. So we need other cheap methods to stay warm.
One of the methods is the wood stove and this is very good as we have a massive living room . Once it is going we don't need any other heating in that room and it runs on free pallets sometimes ! The other thing we do is just to heat up one room with a little electric blow heater. We have 2 of these and these are especially handy when we have to get up and be out for school before the central heating has a chance to get going.
We also drink hot drinks, wear coat and hats indoors until the temperature gets a bit higher and use blankets. We also like thermal underwear and two pairs of socks. As I write this, I've got my thermals on, a cashmere blanket wrapped around my legs and I'm wearing two pairs of socks. I'm drinking a hot drink and have had the electric heater on, but now it's only a few degrees until the thermometer hits 18C so I don't need it anymore.
Good luck with staying warm where you are. I'm off to walk a couple of miles and stay warm with a spot of exercise !