Conventional fireplace are just plain inefficient. The only way to make a significant difference is to install a fireplace insert, which dramatically increases efficiency.

The biggest reasons fireplace are inefficient is that they exhaust large amounts of heated room air up the chimney, and every such cubic foot of warm air is replaced by a cubic foot of cold air infiltrating the building from outdoors.

The second reason is that the heat produced from combustion goes up the chimney without giving up more than a small part of the heat produced.

Inserts make huge improvements in both of these problems.

If you want to do a significant amount of heating with wood, the cost of an insert is worthwhile.