Whenever you use electrical items inside a tent, you need to be careful. While you will see some experts abide against using heaters in tents, it depends on which ones you go with. Ideally, go with those where the flame is not exposed.
Of course, there are also cold weather tents available that sport stove holes. As was seen on this list, such designs can account for wood-burning stoves to allow you to be warm and cozy without ever leaving your tent.