If you're designing, building or buying a new home, or upgrading the heating and cooling system in your existing home, there's an increasingly popular option that can help you get the most indoor comfort and efficiency. Its name: zoning.

According to the Trane Home Comfort Institute, the easiest way to describe zoning is to compare it with lighting. Each room in your home has its own light switch. With individual switches in each room, you don't waste electricity lighting the entire house if you only need to light one or two rooms.

In a similar way, zoning provides individual comfort control within specific, preplanned areas of your home. If you only need to heat or cool one or two rooms, zoning lets you do it more economically and with greater comfort.

In a typical zoning system, thermostats in each room or grouping of rooms -- zones -- monitor the temperature. Whenever a thermostat senses the need for heating or cooling, it signals a central control panel which turns on the furnace, air conditioner or heat pump. At the same time, the control panel also activates motorized dampers in the ductwork to open or close. This directs the heated or cooled air only to the zone or zones calling for it.

Experts at the Trane Home Comfort Institute say zoning offers three significant benefits:

A zoned comfort system quickly adapts to changing conditions within an area without affecting other areas.

For example, many two-story houses are zoned by floor. Because heat rises, the second floor usually requires more cooling in the summer and less heating in the winter than the first floor. A nonzoned system can't completely accommodate this seasonal variation. Zoning, however, can eliminate wide variations in temperature between floors by supplying heating or cooling only to the space that needs it.

Demand for heating and cooling can also vary from one zone to the other during the course of a day. A well-controlled zoned system can quickly respond to these changes, eliminating hot and cold spots and allowing more consistent temperatures throughout the house.

A properly zoned system can be up to 30% more efficient than a nonzoned system.

Why? Because a zoned system supplies warm or cool air only to those areas that require it. It is usually not supplying the whole house all the time. Energy is not wasted heating and cooling spaces that aren't being used.

In addition, a zoned system can sometimes allow you to install smaller capacity equipment without compromising comfort. This reduces energy consumption by reducing wasted capacity.

A zoned system allows more control over the indoor environment because you decide what areas to heat or cool and when.

Consider, for example, cases where children have moved out and some rooms have only occasional use. Or, rooms originally intended for one purpose are converted to other uses. Zoning lends itself well to these situations because it easily adapts to heating and cooling load changes caused by increased or decreased usage, room additions or a change in occupants or lifestyle.

Experts at the Trane Home Comfort Institute say that, applied correctly, zoning systems can provide a very high level of comfort at a very reasonable cost. However, they also say that there is no single best solution to fit all homes. Choosing the right zoning solution depends on the size and layout of the home and the desired degree of control.