From wikip entry for flue: Fireplaces are one of the biggest energy wasters when the flue is not used properly. This occurs when the flue is left open too wide after the fire is started. Known as convection, warm air from the house is pulled up the chimney, while cold air from outside is pulled into the house wherever it can enter, including around leaking windows and doors. Ideally, the flue should be open all the way when the fire is first started, and then adjusted toward closure as the fire burns until it is open just enough to slowly pull smoke from the fire up the chimney. After the flue heats up from the fire, they are easier to move, but also hotter. Hands should be protected when operating the flue lever; and if a new log is added to the fire, the flue must be adjusted again to ensure that smoke does not billow out into the house.
In my and many fireplaces, you have to stick your arm into the fireplace to adjust the damper. I think that would be too hot. IIRC there are others that can be controlled without roasting one's arm, right?
BTW, talked to a friend just now. They had an electric space heater in a bedroom that seems to have set on fire some papers on the bed, which fire spread to the whole bed. The fire department came in less tha 10 minutes, but the house needs 6 months of remodeling.