Also, don't forget about Carbon Monoxide Detectors. If you've been burning a lot of wood, your stovepipe and chimney may have a heavy build up of creosote. If the creosote were to catch fire, your roof could catch fire, too dependent upon what kind of roofing materials you have. So clean out creosote to prevent chimney fires. Your local phone book contains several chimney sweeps who are completely set up to service and maintain your chimney in a fire safe condition.
Gas heaters give off a lot of heat.
They may also give off carbon monoxide. So keep a window open an inch or more in the room in which you use an unvented heater. Keep warm, but don't risk your life doing it. If your gas or oil furnace is not properly maintained, you could be in very big trouble. Carbon monoxide could be spreading throughout your house as a result of a malfunction.