One of my favorite features of my Ecobee WiFi thermostats is the ability to heat or cool a location so that it’s nice and comfortable by the time we walk in the door. For example, our furnace and heat pump at our cabin both use electricity, so I save money on my electric bill by allowing a very wide range of internal temperatures (50F – 90F ) when we’re not there, and only using electricity to heat or cool it right before before we arrive (to make it comfortable) and while we’re there (to keep it comfortable).

Recently, by combining one of Ecobee’s $25 add-on ZigBee Modules with a Leviton 73A00-3ZB wireless load control module ($230 retail, approx $200 street price), I was able to extend that energy savings and convenience to the cabin’s electric water heater.

The Ecobee ZigBee module is primarily designed to control Ecobee’s own branded Smart Plugs, but also enables the thermostat to control a wide number of other ZigBee home automation devices:

Ecobee’s ZigBee module allows you to interface with other ZigBee home automation devices

The Leviton Wireless Load Control Module (which is sold by Leviton, but the labelling seems to imply that it’s built by the highly respected home automation experts at HAI) acts as a remote-controlled switch for power-hungry electric devices… such as a 240V electric water heater.

“Leviton” Wireless Load Control Module

Wiring the control module to the water heater was pretty straightforward. First, I flipped the water heater’s breaker to kill power to the circuit, then disconnected the hot (black) and neutral (white) wires that ran through the metal flex-conduit from the wall and were wired to the to the water heater’s hot and neutral wires.

The control module has three wires: black (hot), white (neutral), and orange (switched load). So I connected black on the Leviton to black (hot) from the panel, joined all three neutrals together (panel, control module, and water heater), then wire-nutted the the orange wire from the Leviton to the water heater’s black wire. Had there been a junction box back on the wall, I probably would have wired the box there. But since the Romex ran straight from the wall and through the conduit, I did it this way.

Wiring the Leviton Control Module

I put back the protective panel and cleaned everything up with the conduit, then used sheet metal screws to mounted the Leviton box to the top of the water heater, and made sure there was a drip loop:

Hardware install done

Adding the device to the local ZigBee network was easy. Similar to setup of a Bluetooth device, I set the Ecobee thermostat to “find” mode, then used a magnet to activate the Leviton and make it “visible” to the ZigBee network. It took about 30 seconds, and then it was “seen” by the thermostat.

When the ZigBee module is installed, a couple new icons appear on the thermostat, including one that says “Plugs.”

New “Plugs” icon on Ecobee

Pressing the Plugs icon revealed the ZigBee plugs that the thermostat could “see:”

Available ZigBee plugs

Pressing the outlet icon (I named my plug “Laundry Water Heater” because I actually have two in this house), exposed the control options for the Leviton:

Control options for the ZigBee control module

It’s clear I could get fancy with the schedule, but for this application, I just wanted the ability to be able to remotely turn the water heater on before arrival, so we’d have hot water when we walked in the door. The Ecobee interface allows great control from the thermostat itself, but that’s not this useful in my case. Remote control is available via the Ecobee website interface, but not available from their mobile app. That’s a big black eye for the Ecobee in my book. Any device that has an app and touts remote control abilities simply must have the ability to perform those remote control options via the app.

The Ecobee allows separate Wake, Home, Away, and Sleep scheduling for each ZigBee plug, which is a great feature. Were I using a setup like this in my primary residence, I’d probably configure a schedule for the water heater so that it doesn’t heat in the middle of the night, thereby saving more energy and money.

Another drawback with this setup is that it would be nice to be able to track power usage of the switched load (the water heater in this case) via the control module. At first, I thought it might be a compatibility problem between the Ecobee and the Leviton device, but with some more research I think I’ve concluded that the Leviton doesn’t report power usage. That’s a shame — that’s very useful info.

The bottom line is that for $25 you can turn your Ecobee into a basic ZigBee control unit (that’s a great deal) but that you have to spend $200 more for the Leviton unit if you want to control a 240V high amp device like a water heater. Controlling a 120V device (such as a lamp) is a lot cheaper, and I suspect that a good chunk of the high price for the Leviton piece is due to its need to support higher than standard loads.

The power is ridiculously cheap out at the cabin (2.5 cents per kw/hour) so it will take a while for this investment to pay off vs. just leaving the water heater on all the time. Although, there’s some admittedly additional value just for the geek points of being able to remotely turn on  your water heater so you can have a hot shower upon arrival. 🙂

The Leviton does exactly what it should do, and does it well. The $200 price tag seems a bit steep, but it doesn’t have much competition… so I supposed they get to control the price of admission for now. The Ecobee also performs its part in this setup reasonably well, but the absence of smartphone app control of the remote devices is a big red mark for me. If they fix that, I’ll come back and edit this post to give them full marks.

As always, I welcome your questions and comments below!