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 ...

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.

The transfer of heat through matter or space by means of electromagnetic waves.

The process of cooling by which a heat absorbing media absorbs heat from one source and radiates the heat away.

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.

A device that releases pressure within a radiator when the pressure inside exceeds the operating limits of the vent.

Materials left over from making nuclear energy. Radioactive waste can living organisms if it is not stored safely.

A naturally occurring radioactive gas found in the U.S. in nearly all types of soil, rock, and water. It can migrate into most buildings. Studies have linked high concentrations of radon to lung cancer.

A construction element used for ceiling support.

A construction material made by compressing earth in a form; used traditionally in many areas of the world and widely throughout North Africa and the Middle East.

The thermodynamic cycle that is an ideal standard for comparing performance of heat-engines, steam power plants, steam turbines, and heat pump systems that use a condensable vapor as the working fluid; efficiency is measured as work done divided by sensib ...

A mechanism used by electric utilities to determine prices for electricity; typically defines rates according to amounts of power demanded/consumed during specific time periods.

The length of time that a product or appliance is expected to meet a certain level of performance under nominal operating conditions; in a luminaire, the period after which the lumen depreciation and lamp failure is at 70% of its initial value.

The power output of a device under specific or nominal operating conditions.

A mathematical representation of the frequency or ratio that specific wind speeds occur within a specified time interval.

The electrical power that oscillates between the magnetic field of an inductor and the electrical field of a capacitor. Reactive power is never converted to non-electrical power. Calculated as the square root of the difference between the square of the ki ...

The unit price of a good or service estimated from some base year in order to provide a consistent means of comparison.

The component of a central receiver solar thermal system where reflected solar energy is absorbed and converted to thermal energy.

Air that is returned from a heated or cooled space, reconditioned and/or cleaned, and returned to the space.

A type of solar heating system that circulate warm water from storage through the collectors and exposed piping whenever freezing conditions occur; obviously a not very efficient system when operating in this mode.