What is Radiant Heat?
Radiant heat is not new. Heating by way of a radiant floor system has been growing in popularity in North America for the last few decades. Europeans have been enjoying the comfort of radiant heating in their floors for most of the last century. Romans were using a convective based radiant floor system almost two thousand years ago. (Although you had to be the Emperor to afford it.) In fact, our planet has been heated by radiant energy as far back as we can remember. Ever wonder why you can get so hot when you're out in the sun during the summer, but it can be sub-zero in outer space? The answer lies in how radiant energy is transferred. Thermal energy can be transferred from warm objects to cool objects in one of three ways: Conduction, convection and radiant. Conductive heat transfer happens when two objects are in contact. Conduction is what can make a cool pool feel great in the heat of summer and a cold lake life-threatening during the winter. Conduction is the reason we learn early on not to put our hands on a hot baking sheet no matter how good those fresh cookies may be. Conductive thermal transfer quickly equalizes the temperature differential between two objects and while beneficial in some situations, it really doesn't lend itself to human comfort. Convection happens as a result of air movement. Traditional forced air heating systems make use of this principle. Air is blown across or through a hot surface. The air picks up some of the heat and then is blown towards cooler objects. The cooler objects pick up some of that heat. One big comfort issue we've all heard about is the wind-chill factor. People have their own built in evaporative cooling system. We sweat, some more than others. As air blows across our skin it takes some of the heat away. To overcome that effect, air temperatures in forced-air heating systems have to be pretty high. Bottom line, it does work. Forced-air is the prevalent type of heating system in today's construction. However, it can produce drafty houses, cold spots, dry or "scorched" air, and as a principle of thermal transfer, convection is easily recognized as the least efficient method. You can see that illustrated in the picture below. Radiant energy is transmitted as an energy wave. Our sun sends radiant energy out in all directions. We receive a fraction of its output as radiant energy. The empty space between us is very cold, but we stay cozy 93 million miles away. The surface of our planet collects that radiant energy and releases it to us by a combination of all three methods. It's amazing when you think about it. Globally, it works well enough to support life as we know it. However, depending on your latitude, elevation, and other local climate factors, you're probably not comfortable enough year-round to forgo some kind of heating system. We utilize the principle of radiant thermal transfer to maximize comfort and efficiency by keeping your feet warm and letting the heat do what comes naturally, rise. You can see in the picture above a representation of temperature differences throughout the space heated by forced-air. A lot of heat can be wasted in the ceiling while leaving the floors cold. This tends to produce drafty spots in the house and really affect your comfort in a negative way. On the radiant side, you can see the floor at about 80F with a temperature of about 65F at thermostat level. The heat is even and comfortable throughout the living space. One builder commented that having radiant heat in the floor was like setting the heating system to "surround" mode. Why Radiant Heat Over Forced Air? Comfort - Nothing compares to the comfort of hydronic, in-floor radiant heat. Combined with the proper cooling system, hot water radiant floor heat offers the most efficient and comfortable living conditions available in any climate. Efficiency- With proper system design and components, no other heating system is as efficient as radiant heat. Radiant floor heat combined with a high efficiency heat source will cost less to heat your home than any other type of heating system. Radiant floor heat combined with the proper fuel, a high efficiency heat source and good building practices will give you dramatic fuel savings and a greater level of comfort over any other system. Your radiant system could use 30% less fuel than the average new forced air heating system. Installing a high efficiency air conditioning system will result in dramatic energy savings year-round. Flexibility- Unlike central heating and air, with radiant heat you can zone different areas of the house to fit your lifestyle. Some of our customers use one thermostat per floor. Others separate bedroom areas and living spaces. We're happy to help with recommendations based on your project plans. Zoning- Unlike central heating and air, with radiant heat you can zone different areas of the house to fit your lifestyle. Allergens- Radiant Heat reduces dust mites and air borne allergens by 60%-90%. No other heating system reduces allergies as effectively as in-floor radiant. Added Value- Use radiant to heat your garage, try snowmelt; a well-designed installation will add more value to your home than the cost of the package. Further answers about radiant heat and installation methods can be found at www.radiantdesigninstitute.org.