SERVING THE DFW METROPLEX “Family owned and operated since 1972” St. Lic. # TACLA019484E 214-742-7252 Glossary R-Value A measure of the capacity of a material to resist heat transfer. The R-Value is the reciprocal of the conductivity of a material (U-Value). The larger the R-Value of a material, the greater its insulating properties. Radiant Barrier In HVAC a thin, reflective foil sheet that exhibits low radiant energy transmission and under certain conditions can block radiant heat transfer; installed in attics to reduce heat flow through a roof assembly into the living space. Radiant Ceiling Panels Ceiling panels that contain electric resistance heating elements embedded within them to provide radiant heat to a room. Radiant Energy Energy that transmits away from its source in all directions. Radiant Floor A type of radiant heating system where the building floor contains channels or tubes through which hot fluids such as air or water are circulated. The whole floor is evenly heated. Thus, the room heats from the bottom up. Radiant floor heating eliminates the draft and dust problems associated with forced air heating systems. Radiant Heat Transfer Radiant heat transfer occurs when there is a large difference between the temperatures of two surfaces that are exposed to each other, but are not touching. Radiant Heating System HVAC term for a heating system where heat is supplied (radiated) into a room by means of heated surfaces, such as electric resistance elements, hot water (hydronic) radiators, etc. Radiator A room heat delivery (or exchanger) component of a hydronic (hot water or steam) heating system; hot water or steam is delivered to it by natural convection or by a pump from a boiler. Radiator Vent A device that releases pressure within a radiator when the pressure inside exceeds the operating limits of the vent. Re-entry Situation that occurs when the air being exhausted from a building is immediately brought back into the system through the air intake and other openings in the building envelope. Recirculated Air Air removed from the conditioned space and used for ventilation, heating, cooling, humidification, or dehumidification. Refrigerant The compound (working fluid) used in air conditioners, heat pumps, and refrigerators to transfer heat into or out of an interior space. This fluid boils at a very low temperature enabling it to evaporate and absorb heat. Refrigeration The process of the absorption of heat from one location and its transfer to another for rejection or recuperation. Refrigeration Capacity A measure of the effective cooling capacity of a refrigerator, expressed in Btu per hour or in tons, where one (1) ton of capacity is equal to the heat required to melt 2,000 pounds of ice in 24 hours or 12,000 Btu per hour. Relative Humidity A measure of the percent of moisture actually in the air compared with what would be in it if it were fully saturated at that temperature. When the air is fully saturated, its relative humidity is 100 percent. Return Air Air that is returned to a heating or cooling appliance from a heated or cooled space. Return Duct The central heating or cooling system contains a fan that gets its air supply through these ducts, which ideally should be installed in every room of the house. The air from a room will move towards the lower pressure of the return duct. Sala Air Conditioning has been serving the DFW area since 1972, providing commercial and residential heating and air conditioning. (Parts, Sales, Service, Installations, and Repairs) Home | Products | Services | Coupons | Contracting  | Contact  | Employment  | About Us   | Sitemap Air Conditioning and Heating Terms A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z R Air Conditioning and Heating Terms A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z R