Question: We have a pre-fab metal wood-burning fireplace. It has inlet vents all around the front face of the firebox for drawing in room air around the fireplace (not into the firebox)- and two heat vents on top of the unit for heating the room. It is gravity flow- and has no fan. It has glass doors on the front. It uses room air for the draft. The house was built in 1978. 1. Is this type of fireplace efficient at all? It seems to heat the room well when we burn it- but it obviously brings in cold air when not in use. 2. Also- although we would like the convenience of a gas insert or log- we also like the charm of burning wood when we have the time to tend it. Is there such a thing as a fireplace insert or log that burns BOTH gas and wood? Answer: This type of fireplace is as good or better than many masonry fireplaces...but still is not heat-efficient in any way. 2. No- you'll have to make the choice before you buy.