Most wood burning inserts today operate with efficiencies in the mid 70% range. A properly sized and operated wood burning insert can heat a couple thousand square feet of living space.
Older, open burning fireplaces are not rated for any efficiencies, but most dealers would agree that if you’re getting 15 to 20% of the heat into your home, you’re doing pretty well. Stop and think about that for a minute. Imagine 100 pieces of wood, all the same size. Now imagine wasting the heat from 80 – 85 of those pieces. It’s lost heat up the chimney. With an open burning fireplace, you essentially have an 8” or 12” hole in your living room with most of the heat from the “campfire” going straight up that chimney. An insert dramatically improves the amount of heat energy delivered to your home. We highly recommend them!