The Rumford fireplace on the right was a more efficient design for radiating heat than the conventional fireplace on the left.
Modern designs make fireplace heating a practical option.
PHOTO: SCOTT BARROW
Profile view of air flow in the Franklin fireplace design.
The fireplace design Ben Franklin developed in the 1740s was intended to prevent smoke from filling a room.
A small, decorative unit.
MOTHER EARTH NEWS STAFF
A kacheloven's performance relies on both air channels and thermal mass