In the last decades of the twentieth century, double height ceilings were popular house additions, however, these items are currently losing favor in the housing market, being considered as expensive to both heat and cool. In an era which is concerned with being environmentally friendly and energy efficient, heating these house additions is expensive and often ineffectual.
How Heat Moves through a Room
Heat passes through from the source to other areas through a variety of ways. Hot objects have something called heat energy. This energy causes heat to move from the hot object into things which are cooler. Heat can be moved in three ways: through conduction, radiation, and convection. In conduction, electrons move from the hot areas to colder parts, moving the energy with them. In convection, heat moves from hot air to cold air. As heat decreases the density of air, it rises, allowing cold air to move into the warm spot and become heated in its turn. In radiation, solid objects pass heat to their surroundings using heat waves, or infrared radiation. The most common methods of heating a room are through convection and radiation.
Heating a Double-Height Ceiling with Convection
Heating a room often involves the use of convection. This is where heat travels from the radiator into the air nearest to it, warming that portion of the air, as explained above, this air then rises. Convected air often does not warm much of the room except the small part near the heat source, and the top of the room. With a standard home radiator, then you can see that the area nearest to the radiator will be warm, but bodies further away from that point may not be. Having a double height ceiling will mean that your hot air will be located at the very top of the ceiling, well away from the living space. Homeowners with double height ceilings often find that their energy bill is high, and they may also resort to bringing in portable heaters in an attempt to adequately heat the room.
Using radiant heat in a room creates a very different movement of warm air. Heat rays travel in straight lines until they come into contact with a solid object, to which they then transfer their hot energy. Ceiling heaters are often used in radiant heating, as they cause air to travel evenly down to objects below. With a double-height ceiling, much of this heat will be lost as the rays will reach the side of the house, rather than the living space. Radiant heat does have some advantage over convection heaters, as infrared rays can go to cold areas before warming up temperate areas.
Underfloor heating can help those with big double height ceiling house additions, as it heats the floor before moving in to other places in the room. This should give a significantly higher floor temperature, meaning that feet can be warmed, and the body will pass the energy upwards using convection. The hot air will eventually reach the top of the ceiling, but the living space below should still be hot enough for comfort.