Underfloor heating matsAdvantagesThermal comfort with underfloor heating mats Radiant heating is arguably superior to convection methods because warm, buoyant air rises wastefully to the ceiling in convection-heated rooms, warming the upper body (often with some discomfort, particularly to the head) but leaving the lower body cooler. In contrast, underfloor heating mats warm the lower part of both the room and the body because when warm air convects from the radiant floor surface, it loses approximately two degrees Celsius at two meters above the floor. This imparts a feeling of natural warmth, since the limbs should ideally be warmer than the head. (The most acceptable indoor climate is one in which the floor temperature ranges between 19 and 29 °C and the air temperature at head level ranges between 20 and 24 °C.) Humidification may still be needed for thermal comfort with a radiant system, but, for a given relative humidity, likely less humidification is needed than for forced-air heating. This is because forced-air systems, when improperly balanced (e.g., because of leaky ducts), can draw in outside air which typically has low moisture content in the winter. [1] Asthma sufferers may benefit from underfloor heating mats because it reduces the airborne circulation of both dust and dust mites. Aesthetics Underfloor heating mats are invisible from above and does not use valuable wall space with unsightly heating equipment. In a sense, the entire floor is a radiator, although, because of its area, it need not reach the high temperatures of a steam radiator. It has a particular advantage in public areas where exposed hot or sharp surfaces can be dangerous and unsightly. Energy Efficiency Air-infiltration heat loss is reduced significantly relative to forced-air systems in which imbalance due to duct leakage can drive infiltration. Infiltration may also be slightly reduced relative to other types of hydronic or electric heating systems because with underfloor heating, the air is only warmed slightly above the temperature of the thermostat setting, so the temperature differential at the outside wall is less, thereby reducing air infiltration due to the stack effect. This is because air infiltration and exfiltration increase as the difference between inside and outside temperature [AT] becomes larger, and so when heated air from a furnace or baseboard heater flows against relatively cold exterior walls, the increased temperature differential results in a stack effect that draws cold air into the house through any cracks [citation needed]. If the boiler water temperature is set to the relatively low temperature required by underfloor heat, rather than the higher temperature typically used in other types of radiators, the boiler may have higher efficiency and lower standby losses. However, this is typically only possible in a boiler designed for condensing operation; in many boilers, the water temperature in the boiler must be set higher, and reduced by a mixing valve. Depending on the piping layout and insulation, there may also be lower heat losses in the water distribution system because of the lower temperature. Electric Systems Electric floor heating systems are very cost-effective solutions for smaller spaces (1-5 rooms) because they are easy to install and have a very low start-up cost. Another advantage of electric underfloor heating over a warm-water system is the floor build up/height. Floor build up can be from as little as 2mm. The electric cables are usually installed onto an insulation board or directly onto the subfloor or padding (under carpet or laminate), then the floor covering is placed directly over the heating system or thinset. Electric underfloor heating also benefits from faster installation times, with a typical installation only taking half day to a day depending on size to install. Also warm up times are generally a lot quicker than "wet" systems because the cables are installed directly below the finished flooring making it a direct acting heat source rather than a storage heater. Electric system used to be supplied as one long continuous length of cable with the consumer having to weave the cable up and down the floor at a pre-determined spacing and making a return loop to complete the circuit. The main problem with this was the installation time taking quite a while, and also the risk of hot and cold spots due to uneven cable spacing, the closer together the cable the more heat was given off, and visa versa. With today’s technology most modern cables have a built in return meaning that you only have one end to connect instead of having to bring the end of the cable back to the start to make a full circuit, these are excellent and make the installation a lot easier. With the introduction of the built in return came the “cable mat” these have revolutionised the electric underfloor heating market due to the simplicity of the installation. Underfloor heating mats have taken the hard work out of the install by having the heating cable already pre-spaced on to a nylon mesh and all you have to do is simply start at your thermostat location and roll it out over the floor until it’s all used up. These save time and offer less risk of having hot and cold spots. One technique is to lay the underfloor heating mats directly onto an insulated concrete floor and then apply tile on top of it. This type of system can be turned on at night when electricity rates are low, and then allowed to warm the house during the day by relying on the radiant heat held within the thermal mass of the concrete. Sometimes, in order to mimimize floor buildup, a screen or carbon film heating element is used. These systems are generally used under laminate or similar types of flooring. In comparison to hydronic systems, electric underfloor heating mats are more efficient and cheaper to run. Upfront costs may be more for an electric system but the efficiency rate of an electric system contrasted with no maintenance and the fact that it only runs when it needs to, gives the electric system a more cost effective advantage over traditional forced air and hydronic heating solutions.
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