Dimmer switches that can be used to control the brightness of floor lamps, table lamps or permanentaly installed lighting fixtures in the home have been around for years, but they have become more popular than ever in the last few years due to the increasing interest in saving energy and money.

In addition to cutting down on energy consumption (by reducing the wattage consumed during much of the time that the lamps are in use), dimmers help extend the life of the bulb, and thus also save money on replacement costs.

All modern light dimmers sold for use in homes or apartments are remarkably compact solid state devices that control the flow of current through them when a knob or wheel is turned (or in a few cases, when a sliding handle is moved).

The original dimmer switches were all wall-mounted units that were used to control ceiling and wall fixtures or outlets, and this is still the most widely sold type. It fits into a standard wall receptacle or outlet box in the same way that a conventional coggle of pushbutton wall switch does.

To change from a standard switch to a dimmer switch, first shut off the power to that circuit by pulling the fuse or throwing the circuit breaker, then take off the face plate.

Next, remove the old switch by taking out the two screws which hold it in place and then pull the switch out from the wall. Disconnect the wires leading to this switch (don't distrub any other wires in the box) and then reconnect them to the terminals on the new dimmer, or to the two lead wires attached to the dimmer (in the latter case "wire nuts" are used).

In most cases the original switch plate can be used again since the rotary knob covers the slot through which the toggle lever originally protruded. However, some dimmers require a special plate or cover, and this almost always comes with it.

Wall type dimmers switches are usually rated for a maximum of 600 watts, so it is important that care be exercised when it is used to control wall outlets where numerous lamps with a total wattage exceeding this could be plugged in (heavier duty models are available where required). Most are intended for use with incandescent bulbs only, but in recent years special fluorescent dimmers have also been made available for use with rapid-start-fixtures.

All wall-mounted dimmer switches provide infinite control of the light's brightness, from fully on to fully off, but some (called rotary switches) must be turned all the way past the lowest level to turn them fully off.The others (usually higher in price) have an added push-pull feature - that is, at any position of the rotary knob the light can be turned off by pushing the knob in, and tuned back on by pulling it out. This permits on-off control without disturbing the predetermined light level each time.

In addition to conventional single pole (one-way) switches, dimmers are also available in double-pole models to replace three-way switches (where one light is controlled from two different places). Some of the newer dimmers also have lighted knobs which simplify locating the switch in the dark. Prices for wall dimmers generally vary from about $4 for the lowest priced rotaries, to about $7 to $8 for the pushpull models.