As energy costs have increased, appliances have been redesigned to consume less. Walls, roofs, doors, and windows now are built to more stringent insulation standards, and membranes meant to reduce air leakage through walls and around openings are incorporated as a matter of course. These changes have several ramifications for the design and construction of masonry fireplaces. Making provisions for these changes is important when designing and building masonry fireplaces for today's more energy- efficient homes. Heat from a wood-burning fireplace can be used in several ways. One is to provide a masonry mass that absorbs, stores, and slowly reradiates heat energy back into the room. Another approach is to maximize the output of high-intensity, short-wavelength radiant heat. the third option is to let the fire heat air, then circulate the warm air to make the room warmer. To make the best use of its heating ability, always locate the fireplace wholly within the building, not through an exterior wall. Among the most successful alternatives to traditional fireplace designs are the Rumford-style fireplace and a variation called the Rosin (both named for their inventors).