The easy (and lazy) way to wire a ceiling fan is to use a single switch for both the fan and the lights. The switch then controls both fan and lights and if independent control is desired, it is achieved through pull chains. This configuration greatly limits home automation control of the fan and lights.
By providing separate switch control of the fan and lights, the lights can be dimmed and the fan can be started and stopped based on room temperature. When controlled by a single switch, either of these solutions is impractical.
How Ceiling Fans Work
Ceiling fans with lights typically have four wires: black (fan hot), blue (light hot), white (neutral), and green (ground). When connecting both the fan and the light to a single switch, the black AND blue wires from the fan are connected to the black wire from the switch using a twist-on wire connector. The white neutral wire is then connected to the white wire on the switch.
When connecting the fan and the light to separate switches, connect the black “fan” wire to the black wire on one switch and the blue “light” wire to the black wire on the other switch. Because most electrical ceiling cable has 3 conductors, the blue “light” wire can be electrically connected to the switch through the red conductor in the ceiling cable. The last step is to connect the white neutral wire on the fan to the white wired in the ceiling cable and then to the white wires on each switch. Caution: Always turn off circuit power at the breaker before attempting any electrical wiring.
Home Automation Control of Ceiling Fans
Using two separate switches provides you the ability for home automation control of the fan and light. Fan ceiling lights often use multiple bulbs making them very bright when at full power. Configuring the light to work off its own switch allows you to use a home automation dimmer switch so you can vary the light intensity. Never place a fan on a dimmer switch as this may cause the fan to hum.
Configuring the fan to work off an on/off (non-dimming) switch allows home automation control of the fan. Using independent control of the face has many useful applications including program the fan to turn on and off based on room temperature.
Using Your Fan To Save Money
Ceiling fans increase air conditioning systems efficiency by circulating the room air, thereby reducing how hard the air conditioning has to work. Turning the fan on when the temperature raises, cuts down on your air conditioning bill. Turning the fan off when the temperature is low, saves on unnecessary electrical consumption.
Many ceiling fans have 4 to 5 light bulbs. If each bulb is 100 watts, the room will be too bright for most uses and power consumption will be high and expensive. Using a dimmer switch to reduce power consumption to 50% can greatly reduce your electricity consumption while still providing adequate light in the room.