How To:
Understand Radiant Heat
Why Radiant Heating?
Radiant Heat is a form of heating a livingspace that has been in use for centuries. It was used in ancient Rome and has been in use in Korea for millenia. The modern form of Radiant Heat uses either heated water piped below a floor, or low-voltage electrically heated cables under the floor covering. This form of heating has many advantages over traditional heating.
Traditional Heat
In a traditional forced-air heating system, hot air is ducted through the system and blown into your livingspace. And in a convection heating system, air is warmed by a radiator or baseboard heater, and then dispersed through the room by convection. The rooms which are being heated therefore have areas which are much warmer than others. For example, the air near windows would be much colder than the air next to the heat register on the floor. In addition, since heated air rises, the air near the ceiling is much warmer than the air near the floor - resulting in hot heads and chilly toes! To keep the entire room at a comfortable temperature, the system has to warm air up to a temperature much higher than the average room temperature desired. This is inefficient - and wasteful.
Radiant Heat
In a home heated by radiant heat, the floor or walls act as a giant radiator, warming up everything they touch. Since the area of the floor is so large, the temperature can be much less than that of a traditional radiator. In the average radiant heat system, the floor surface normally is around 80°F. When the warm air convects heat from the floor, it loses heat as it rises, resulting in a much more comfortable living environment since the air around your head is cooler than the air around your feet. In addition, since hot air isn't being forcibly blown out of a traditional system, asthma and allergy sufferers benefit because dust and dust mites are not circulated in the air. Aesthetically too, radiant heat is more attractive - simply because it's invisible! Radiant heat is hidden under the floor or in the walls, so your heating system is completely out-of-sight.
How does Radiant Heating Work?
Very simply. Warmth from the heating system heats your entire floors surface, creating a giant radiator. This surface radiates heat to every other object it touches, including you and the air around you. Who hasn't hesitated to step out of the shower onto a cold tile floor, or to get out of bed on a chilly winter morning? With radiant heat these problems are solved, since your entire living environment is heated to a comfortable temperature. And since the floor makes such a efficient radiator, the heat necessary is much less than you would expect - normally around 70°F to 85°F.
Electric Radiant Heat
Electric Radiant Heat is normally cheaper than a hydronic system, but that doesn't necessarily mean it's always better. In an Electric Radiant Heat system, there are special heating wires woven into a mat which is then installed into your flooring. This matting comes in many different sizes and can be cut to fit the area you need. It can be installed below any floor surface, whether wood, carpet, tile, or vinyl. The wattage used to power the system is very low, and it emits zero measurable EMF (electromagnetic fields). The wires heat up quickly and efficiently. These mats add as little as 1/8" of an inch to the thickness of your floor and usually heat the floor to the desired temperature within a few hours. But on certain floors, like hardwood, a quick temperature change like electric radiant heat provides puts a lot of stress on the floor material.
These electric systems are very cost-efficient. Their cost can be calculated by determining the square footage of the area you plan to heat, and multiplying that by the wattage of the system. Their set-up is also fairly inexpensive and easier than that of a hydronic system. In areas where the electric company offers discounted off-peak rates, the electric system can run at that time and the thermal mass of the floor will retain the heat for a number of hours. However, in larger areas their cost begins to increase.
Hydronic Radiant Heat
Hydronic Radiant Heat Systems consist of special PEX tubing which is circulated underneath the flooring of the area to be heated. Any area that you want to heat can be properly controlled. This could be a 10'x10' area within a 60'x60' room, or a 100 acre greenhouse. Outdoor sensors working in conjunction with indoor controls adjust the temperature of water to be heated accurately, to achieve the needed indoor temperature desired. Warm water is then pumped through the tubes, thereby heating the flooring above - and the tubing can be as small as 3/8ths of an inch! The benefits are incredible - the floor will be a comfortably warm temperature, and the flooring material will retain that heat even after the system is turned off. A hydronic system initially will cost more than an electric heating system - the tubing and water heating materials are more expensive, but the source of energy for heating the water is much more flexible. In addition to a conventional hot water heater, there are also high efficiency modulating boilers which can be used for this purpose. Other methods which can be used for this purpose are tankless gas water heaters, solar heaters, indirect water heaters, photovoltaics or an electric boiler. Many kinds of water heating systems are comptatible with a hydronic system because the water doesn't have to be very hot; it only needs to be heated to the desired temperature, which is normally around 70°F to 85°F. This makes a hydronic system very environmentally friendly; it doesn't necessarily depend on fossil fuels for a fuel source and can be easily modified depending on the fuel source available without changing the tubing in the floor.
Installation
Both types of Radiant Heat Systems are more flexible in their installation options than traditional heating systems. Hydronic radiant uses light weight small tubing, while electric uses woven mats. A heat exchanger and back flow preventer must be used to keep potable water protected from the closed loop radiant system. Radiant systems can be installed in concrete before the slab is poured, as well as on top of installed wood subfloors. They can be covered with poured floor coverings or rolled floor coverings. Both types of radiant, electric or hydronic, can be installed over the sub floor or between joists from underneath for new work, remodels and additions as well as heating the upper floors of your home. Radiant can be installed under tile, marble, wood, carpet and concrete floors. With insulation installed under radiant the heat is directed to the area to be heated. Radiant Heat is quick and easy to install, and is ideal for new construction, remodels or retrofits.
Other Uses of Radiant Heat
In many cities around the world, Radiant Heat has been used for snow-melting applications. Among these cities are Holland, Mich., and Beaver Creek, Colo. Their citizens are kept safe from slips and skids on ice, and shoveling or salting snow has become a thing of the past. It has been proven that the energy used by trucks and loaders to remove snow and ice is more than is used for radiant snow melt. In addition, with radiant the city's landscapes do not get damaged and snow and ice melt chemicals aren't tracked into buildings. This same technology can be used to heat your driveway, steps, sidewalk, gutters, downspouts and eliminate snow and ice buildup. The purpose of heating a driveway, sidewalk, or road, of course isn't the same as heating the interior of your home; temperatures are kept only warm enough to melt the snow or ice accumulating on the ground. There are outdoor controls that can sense if it is going to snow and turn on radiant snow melt systems when needed.
Hydronic radiant heat has also been used in sports stadiums, to keep the turf green even through the cold season. Natural grass won't grow for long in freezing temperatures, but with Radiant Heat keeping the soil conditioned, the grass will stay green all winter.
Radiant Heat can be used to keep heated pools warm. It will keep a consistent temperature from the bottom up, and it doesn't need to be winterized. They also run at different times of the year as an indoor radiant heat system, keeping costs down. And they don't churn the water, keeping vanishing-edge pools looking serene.
In addition, in a patio area, uou could extend your season of outdoor enjoyment. Rradiant could be installed underneath decorative pavers, concrete, or many other types of outdoor surfaces. Using a radiant heating system the concern of clearance to combustibles would not be a problem.
|
|
