Radiant heating systems installed under wood flooring have raised concerns among flooring manufacturers. The people who make and distribute the systems, however, claim there are no documented cases of floor damage caused by the radiant heat. Such systems, which originated in Europe, are becoming increasingly popular in the U.S. according to a spokesman for the Wirsbo Company. Wirsbo is based in Sweden with a wholly-owned U.S. subsidiary. The company reports it has sold roughly half a million radiant systems worldwide, of which 10 to 15 percent are installed in wood floors. Since wood is vulnerable to changes in temperature and humidity, flooring manufacturers are worried about the effects of radiant heat on their products. The National Wood Flooring Association (NWFA) flatly advises against the use of
