Question: I have an open brick fireplace in the living room built about 15 yrs ago it was in the house when we bought it People say that an open fireplace sucks heat out of the house when the fire is on and the doors are open . Is that True ? I Feel heat from the thing when the doors are open & the fire is on . What is your opinion and what is the best way to operate the doors open - part open . closed ? I'm a new home owner and never had to learn about fireplace operation . Thought it was easy . Answer: You are feeling only the radiant heat..which comes out the front of the fireplace like rays from the sun..in a direct line. What you are not seeing is the escape of heated house air up the chimney. If you want heat from the fireplace it's best to put a stove or insert into it...there are also some special grates that help a fireplace heat better.If you are going to use it open- leave the doors open when the fire is hot- and close them when it's lower and/or going out.