If you decide to add a space heater, please look into the quartz infrared heaters. We heat our entire house (small but all chopped into small rooms) with the Eden Pure brand heaters, no furnace....we use three. They plug into standard 110 volt outlet and are very effecient. Our electric bill only went up $30 per heater per month, so total cost to heat house in the dead of winter was $90 per month. Not bad for electric heat. There are different brands to choose from, but I can only testify on Eden Pure.