Hold your hand over a hot cup of coffee and feel the heat. The typical conclusion is that heat rises. Typical maybe, but incorrect! "Hot air" rises but "heat" can travel in any direction. That is why you can feel the heat of the cup when you place your hand to the side of it. Radiant energy transfer is caused by a warm surface giving up its heat to a cooler surface. Whenever there is a temperature difference between two surfaces, both surfaces will attempt to equalize. Radiant energy travels through space without heating the space itself. It only turns into heat when it contacts a cooler surface.
Our human comfort relies just as much on radiant heat transfer as it does on air temperature, yet the majority of heating and air-conditioning professionals think only in terms of air temperature. (*Adapted from RPA-Info web site.) As a result, Americans are missing out on a truly comfortable living environment in their homes and businesses. By controlling both the air temperature and the radiant transfer of heat to nearby objects, radiant systems deliver a comfort that is unsurpassed. A radiant "panel" or radiator can be easily mounted on any flat surface. The only requirement is that the surface be sufficiently large. The larger the surface, the lower the actual surface temperature required. A wall radiator may have a surface temperature of 180°F, while an 81°F heated floor will do the same job. With radiant heat, the room and every object in it become radiators. Typically, the temperature in a radiantly heated space matches your skin's temperature thus eliminating heat loss from your body. Because of this, the room actually feels warmer, even though the actual air temperature may be cooler. As a result, radiant heat offers unparalleled comfort and decreased energy bills!
Over the past 50 years Americans have typically heated their homes by blowing warm air from ceiling mounted registers. This crude attempt at warmth sacrifices comfort for over 200 days of the year in the Puget Sound region. With a forced air system, because warm air rises and cold air sinks, it's always cooler on the floor. The average contractor will rarely inform you that ducted air systems have the lowest comfort rating and the highest monthly energy costs of any heating system. The contractor simply installs the system in the home because it costs less initially. Period.
Air is a horrible conductor of heat. While the air coming from the vents may be warm, it does not warm the objects in the room or radiate that warmth throughout the room. A hydronic radiant heating system takes advantage of the superior conductive properties of water to more efficiently heat your home by heating the objects in it. When the contractor finishes your home he leaves, but you stay. Whose comfort is at stake? Shouldn't you have a choice in what type of heating system is installed in your home? It has been proven that a home with quality radiant heating has supreme comfort, far lower operating costs, is absolutely silent, and builds equity. The slightly higher installation cost of a radiant system is always offset by the lower heating bills, not to mention the supreme comfort provided by a hydronic radiant heating system. If designed and installed correctly, a radiant heating system with Viessmann boilers will last the lifetime of the residence. And most of all, you'll be incredibly comfortable. Isn't that what you really want?
It is the only heating system that matches the exact temperature requirements of the human body. Our body temperature is warmest at our head and circulation is poorest at our feet. That's why the human body is most comfortable in a room that is warm at the floor and slightly cooler at head level. Forced air heating systems which blow scorched air are the exact opposite of what the human body requires -- hot at the ceiling and cold at the floor. With Radiant Floor Heating it is also easier to zone heat your home or building. Work areas can be kept at a comfortable working temperature, while bedrooms can be kept slightly cooler for sleeping. At the same time, living rooms, bathrooms and entrances can be kept slightly warmer. In commercial buildings and factories, Radiant Floor Heating increases productivity and helps reduce health problems associated with working on cold, damp floors. In barns you won't have any drafts and the floors will be warm and dry. In nursing homes and hospitals, the warm floors mean the highest comfort for the occupants. Management of course enjoys the low fuel costs and minimal maintenance associated with radiant heating and Viessmann boilers. With Radiant Floor Heating water is used to carry heat. Water is one of the best conductors of heat; it can be circulated positively and its temperatures can be accurately controlled so you get a more even heat with less temperature fluctuations. Whether you have hardwood, vinyl, carpet, ceramic tile, or concrete floors, they'll all be "barefoot warm" for the most comfortable living and working environments.