Home House & Components Systems Electrical System

Smart Light Switches

Updated: Oct. 15, 2021

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Illuminated switches

Illuminated toggle switch

Illuminated rocker switch

It sounds like a joke: How do you find a light switch in the dark? Illuminate it, of course. These great little inventions use a tiny bit of electricity from the circuit they’re on to light a small LED or neon bulb. A light up switch installs as easily as regular switches, but be aware that these switches work fine with some CFLs but not so great with others.

For a broad selection of illuminated toggle and rocker switches, visit kyledesigns.com. You’ll find clear, white and red toggles and black, white, ivory and other colors of rocker switches. Prices range from $7 to $40 through our affiliation with amazon.com. The Web site also carries a huge and reasonably priced selection of low-voltage lighting, switchplates and other items.

Occupancy and vacancy sensors

Residential occupancy and vacancy sensors have come of age. Most residential sensors use passive infrared (PIR) technology to detect heat and motion and turn lights on and off accordingly. They can cut lighting costs by 50 percent in rooms where lights are frequently left on when no one is in them. Wall-mount sensors install just like a light switch and are available as switches or dimmers. Most require a neutral wire, but there are a few models that don’t. The smartest sensors are designed to screen out background interference and detect small movements and natural light. They also work with LED, CFL, incandescent, halogen and other bulb and load types.

Occupancy vs. vacancy sensor—What’s the difference?

An occupancy sensor automatically turns lights ON and OFF. Great for areas where lights are accidentally left on a lot, like in a kid’s room, or where your hands are full, like in a laundry area. A vacancy sensor has a manual ON and automatic OFF (you can preset different times). Good for bedrooms, so the light doesn’t automatically turn on if a spouse enters while you’re sleeping, or in the hallway, so your pet doesn’t trigger the light.

Bath fan timers

Bathroom timer

Lutron’s Maestro MA-T51 Countdown Timer (about $31 through our affiliation with amazon.com). This timer can be set to operate the fan or light for 5 to 60 minutes before turning off automatically. It also has a tap-twice manual override. Orange LEDs indicate the time remaining before the device turns off. This single timer does not require a neutral. It’s also available as a dual timer for both light and fan control. Learn more at lutron.com.

Humidity-control bath fan

Broan’s UltraSense bath fans ($250 to $550) automatically turn on when they detect humidity at the ceiling and turn off when humidity levels fall. These fans are available in single- and multi-speed versions. The latter automatically increase their speed to remove shower steam as quickly as possible. Models with motion sensors increase the fan speed automatically for humidity and odor control when someone enters the room. Visit broanultra.com.

Timers for bath fans are important because excess humidity can cause everything from window condensation and mildew to moisture and rot inside walls. Timers connected to exhaust fans must be rated to run electric motors, which makes them more expensive than those running incandescent lamps. Some new wall switch timers have dual controls for turning off both lights and fans after a preset time. For the ultimate in smart bath fan timers, buy a humidity-sensing fan designed to automatically turn on and off as moisture levels at the ceiling rise and fall.

Outside lighting timers

Instamatic’s E1600 Series In-Wall timer

Leviton’s Vezia VPT24-1PZ timer

Automated outdoor lighting is convenient, but the smartest timers are astronomic versions that turn lights off and on from a memory of 365 days of sunrise and sunset times based on your home’s location. This feature is particularly useful if you live in a northern climate which has a wide range of daylight hours from summer to winter. Simply find the longitude and latitude of your home at http://www.worldatlas.com and enter it into the timer. The timer automatically calculates the sundown “turn on” time. Then choose either a set run-time or let the timer turn the lights off at sunup. Such timers include:

• Leviton VPT24-1PZ (shown here)
• Intermatic EI600WC
• Tork SS721ZA
• Pass & Seymour RT24W – Available at your local home center.

Those with randomized settings can vary on and off times, which adds a heightened level of security by fooling burglars into thinking someone is home when you’re away. The newest (and most expensive) astronomic timer switches are compatible with CFL and LED bulbs in addition to incandescent and halogen bulbs. Non-compatible timers can cause CFLs to flicker and shorten their life span.

Dimmers for CFLs and LEDs

You can save up to $55 a year by replacing an incandescent bulb with a dimmable LED and using it regularly at low levels. Beyond energy savings, dimmers add comfort and convenience. However, dimming technology has had a hard time keeping pace with advances in CFL and LED bulbs. Problems include:

• Reduced dimming range. Unlike incandescent bulbs, most CFL and LED bulbs will not dim to very low levels. Some dimmable LED bulbs can get close, but it depends on a specific bulb’s circuitry.
• Lights dropping out. CFL and LED bulbs will sometimes turn off before the slider reaches the bottom.
• Lights not turning on. After you dim a CFL or LED bulb, it sometimes won’t turn on until you move the dimmer slider up. This “pop-on” effect can really be frustrating in a three-way situation where a light can be controlled from several switches, not just using the dimmer.
• Lights turn off unexpectedly. Dimmable CFL and LED bulbs can be affected by line voltage fluctuations and they can turn off (not just dim or flicker, like incandescents) when a hair dryer or vacuum cleaner is used.

The good news is that dimmer switch technology is improving. The newest switches work well and can effectively dim mixed light sources on the same circuit. The bad news is these switches are pricey and they require pricey dimmable LED and CFL bulbs (they also work fine with incandescent and halogen bulbs). A list of compatible bulbs can be found on manufacturer Web sites. Some require a neutral and some do not, so check the packaging carefully.

Check the wiring before you buy

Switch without a neutral wire

If your switch is wired like this one—connected to a wire wrapped with black tape and a black wire—both wires are hot and neither can serve as a neutral.

Programmable timer packaging

The dimmer packaging will usually tell you if the dimmer requires a neutral wire.

Many of the new, sophisticated smart switches require a neutral wire to run the circuitry inside the switch—particularly those compatible with LED and CFL bulbs. Before you buy a new switch, check the packaging. Most will specifically tell you if a neutral is required (Photo).

To see if you have a neutral wire in your switch box:

• Turn off the power and use a noncontact voltage detector to check that the circuit is off before you remove the cover plate.
• Remove the cover plate and unscrew and remove the switch. The photo shows one common situation without a neutral wire.