Here's the background - this summer we bought a mid century house with 2 regular masonry fireplaces common from the era. It's a fixer, so we're prioritizing projects. The long term plan is to put a gas insert in the living room, and a wood insert in the family room for backup heating. The central heat is oil, which we don't want to keep for too long. Plan on that is to replace with a heat pump either this summer or next. I like burning wood, don't mind the cut/spilt/stack, it's good exercise. But the old fireplaces are so inefficient it seems like I'm spending too much time/money on the fire for the heat it's putting out. My question is - is there an easy way to (slightly) improve the efficiency of these old fireplaces in the short term, or am I better off plugging the chimney until we get a good insert? Living and family room are the same style, except family room vents to the left chimney.