Under floor heat is a heat source, either electric or hydronic, embedded in the floor of a structure. This is most commonly done by installing tubing before pouring a concrete floor as shown below, but can also be added to existing flooring with products designed to conceal the heat source beneath the finished floor. With these systems it is not unusual to keep the air temperatures lower than one normally would with a conventional central air system, since objects and bodies are heated rather than the ambient air. Radiant floor heat is also utilized to provide for keeping sidewalks and driveways free of winter ice and snow. Hydronic heat for these systems can be provided by boiler, water heater, heat pump, or solar systems. Proper installation is critical for efficient operation.