It seems to me that all the radiant "experts" are recommending high-efficiency water heaters for radiant floor heat as opposed to boilers. Yet I keep hearing things like "As a source of radiant heat, boilers are clearly different from water heaters. A central heating system is best served with an ASME-certified boiler as a heat source. The versatility of such a boiler allows a hydronic heating system to operate at its full potential." What am I to believe?