Should You Get a Wi-Fi Thermostat?

Is a Wi-Fi enabled thermostat right for you?

A Wi-Fi thermostat connects to your home’s wireless Internet service and lets you remotely check and change the temperature in your home from an app on your smartphone or tablet. When Wi-Fi thermostats first came out, the buyers were mainly snowbirds who wanted an alert if their furnace conked out while they were down south. That’s not the case anymore. In fact, Wi-Fi thermostats are quickly becoming standard equipment for new homes. If you’re considering upgrading your thermostat to a high-tech Wi-Fi version, here’s what you need to know.

By the DIY experts of The Family Handyman Magazine

6 reasons you might want to get a Wi-Fi thermostat

  1. Travel If you live in a cold climate and travel, you should definitely get a Wi-Fi thermostat to keep tabs on your furnace when you’re away. In cold weather, a furnace breakdown can endanger pets and plants and lead to frozen pipes and catastrophic water damage.

  2. Easy programming

    Setback thermostats save energy but are a pain to program. If programming your current setback thermostat drives you nuts, you’ll like the ease of programming a Wi-Fi unit. Just download the app and enter the temps and times on your phone or tablet.

  3. No need to reprogram when your schedule changes

    If you have a variable schedule, a typical setback thermostat won’t adjust to your changes. But a learning Wi-Fi thermostat will. It detects when you’re home and away, learns your schedule and calculates a setback scheme to match your routine. Some learning thermostats also offer a “geofence” feature that tracks the location of your smartphone and operates your setback settings based on when you enter or leave a geographic radius around your home. So, for example, it can crank up the heat when you’re returning from a trip and are a few miles from home.

  4. Change the temp from anywhere

    Feeling too hot or cold but don’t want to get out of bed or your comfy lounger to adjust the temp? Just reach for your smart device, pull up the app and knock the temp up or down a few degrees. You can also warm up the house just before you arrive there—Wi-Fi thermostats offer the convenience of adjusting temps from wherever you are.

  5. Monitor your HVAC system

    Some Wi-Fi thermostats monitor the efficiency of your heating/cooling system and alert you if the efficiency drops because of a dirty air filter, clogged evaporator or condenser coils, low refrigerant charge, or other problem.

  6. They’re cool!

    You can get units that display your digital photos, play your tunes, change color to match your walls, display the outside temperature or work with multiple sensors. If any of these features sound good, read on to find out if a Wi-Fi thermostat will work in your home.

The hottest Wi-Fi thermostats

There are dozens on the market ranging in cost from $110 to $300. You’ll find some at home centers, but begin your shopping online to get a full picture of what’s available.

DIY install?

Professional thermostat installation runs about $75 if you combine the installation with a regular seasonal checkup. We think that’s a bargain. But if you feel comfortable wiring it yourself, you can save the money. Just make sure you shut off the power and double-check your wiring to be sure wires don’t touch at the terminals. If you’re not careful, you can easily burn up a transformer or blow the circuit board’s main fuse. In that case, the service call will cost more than what you saved by installing it yourself.

Wiring issues & solutions

A common (“C”) wire provides a return electrical path (like a neutral in a 110-volt electrical system) so the thermostat can get power 24/7. If you don’t have a “C” wire at the thermostat, you have two options: Buy a Wi-Fi thermostat that doesn’t require one (it’ll say “No C wire required” in the specs), or install a four-to-five wiring adapter. The “No C wire” style works well in most applications. But if you don’t run the heat or A/C often, the batteries may wear down quickly.

If the main circuit board on your furnace or A/C has a “C” terminal, install a four-to-five wiring adapter to get 24-hour power to the new thermostat. One choice is the Add-a-Wire, No. ACC-0410, from

Three things to check

  1. Test your Wi-Fi signal

    You must have a strong Wi-Fi signal at the thermostat location. Stand next to your existing thermostat and stream a video on your smartphone or tablet. If it streams smoothly, your Wi-Fi signal is adequate for a thermostat.

  2. Check the wiring

    Turn off power to the furnace and A/C and pop the thermostat off the base plate. If you find two thick wires, you probably have 220-volt electric heat, and a Wi-Fi thermostat won’t work. If you have skinny 18-gauge wires, you have a low-voltage system, and it’ll probably work with a Wi-Fi thermostat. Next, look for a wire attached to the “C” terminal. If you find it, any Wi-Fi thermostat will work. If not, you’ll have to buy a “No C wire required” thermostat or install a wiring adapter (see “Wiring Issues and Solutions,” above). And, if your existing thermostat displays the outside temperature or allows you to adjust the settings on your humidifier, it’s probably a digital unit, and an analog Wi-Fi unit won’t work without professional rewiring.

  3. Determine the needs of your heating and cooling system

    You’ll need to know what type of system is in your home and how many stages of heating and cooling it has so you can buy a thermostat to match. If you don’t know the specs on yours, find the unit’s model number (usually on a plate inside the cover panel) and look for the specs online, or call the installer and ask.

Install a Wi-Fi thermostat without rewiring

If you’ve checked into installing a Wi-Fi thermostat but discovered your house doesn’t have a common “C” wire, here’s a workaround. Buy a four-to-five wire adapter. The adapter provides a “C” connection using whichever wire isn’t in use at the time. Install the control box inside the furnace and connect it as shown here. Then install the diode device up at the new thermostat. Once all the wires are connected to the base plate, push the excess wires and diode inside the wall cavity.

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