Electric Heat 120/240v, how to use a 24vac Smart Thermostat on these systems, and should I?
Posted on: April 4, 2017, by : geek1

(edited Oct 15, 2017)

The Smart thermostat has evolved in the recent years to allow for control and management over the internet, and between devices using wireless short range communications, like bluetooth. Nest, Ecobee and Honeywell Thermostat imageThese newer Smart thermostats have a combination of sensors to enable advanced features. There’s lots of great reviews on the current products on the market, and the top players will continue to change, but at the moment, Nest, Ecobee and Honeywell are up on the list, they have a few different features over each other, but all include some smart thinking built in or via the cloud.

Smart Thermostats, at least most of the current models, are targeted to general masses, the 80% of users who have the standard 24vac thermostat control, but what about those of us with Electric radiators, or radiant floor heating, or electric baseboards requiring control of the 120/240vac power to adjust heating. The standard 24vac Thermostat cannot control 120/240v electric heat without the addition of a Relay capable of handling the higher current needs of electric heat.

Lets quickly explain how the technology parts add up to make up the total cost for a standard 24vac Furnace vs 120/240v electric baseboard.electric baseboard heater image

  • Smart thermostat ~$300
  • Installation ~$65
  • Total for 24vac installed Smart thermostat ~365.00
  • Add 120/240v Relay per 3500 watts of electric heat ~$100
  • Installation and integration of Relay with smart thermostat ~$65
  • Total for Electric Baseboard heater installed Smart Thermostat and relay ~$530

Electric Baseboard heaters are commonly controlled with a thermostat in each room, so take the above math, and multiply it by each room controlled thermostat. 4 room, x $530 = $2,120.00, doesn’t look like a good investment as a renter, but if you pay the electric bill, and your paying more than $100/month, just for the power, not service charges. Then $2k investment is worth looking at.

As the technology changes, we are starting to see some more cost effective solutions being made available, some are approaching the Smart category, but not quite there yet. Here’s a Nuheat Signature Electric thermostat, these are usually used to manage the room or floor temperature when an Electric radiant floor system is installed, therefore these come with a wired temperature probe to connect to the Nuheat Signature Thermostat imageNuheat Signature Thermo detail imageThermostat, it supports schedules and an app, but currently not intuitive enough, so they made it “Work with Nest”. Basically when the Nest senses the home is empty, or you’ve set it to away mode, Nest tells the Nuheat Signature thermostat to turn off, nobodies home. This unit is also around $300, but has a build in relay to control the 120/240v electric heat, so you save $100 on the relay, and another $65 on the installation per room. Not a bad option, it includes some nice bells and whistles that should please most people. The Display is well lit and adjusts for room light, shares the current local weather, and actually looks really nice. I expect this device to evolve and get a little smarter, and if you are a keener, you can start to play with Online tools to connect your devices. But using WinkIFTTT or KAA aren’t ideal for controlling life/home safety devices like a thermostat, at least not yet. I’ll link a future post here talking more about  IoT’s(Internet of Things) devices and ways they can communicate.

A recent customer and I have been looking for a cost effective solution for his condo, lets say its about 1200 sq ft, has 1 main room, and 3 other rooms all with their own old school 240v wall dial thermostat. So to fully wire up his home, we looked at the following options:

  1. 4 Nest E Smart thermostat, and 4 Relays, that’s $200×4 and $100×4 = $1200, in technology alone, some may charge another $20-50 for misc parts, wires and screws, etc, But we don’t. 4 Nest Installs and 4 relay installs, these individually add up to 8 hours, but we all know the majour part is the first one, so we’ll use 6 hours at $65 = $390. Approx 2 of the 6 hours is educating the customer on their system and Smart thermostat of their choice, if they are already fluent in the use of the new devices, install time can be reduced. We expect training required for our customers new install. Key benefit, maximum energy savings, every room will turn itself off when empty, Grant total $1990.
  2. 1 Nest E Smart thermostat, 1 Relay, and 3x Nuheat Signature thermostat, that’s still $ 200x 1, $300×3 and only $100×1 (relay for the Nest connected Electric heater) = $1,300 and installation becomes simpler, 4 hours for install and training, $65×4 = $260. Key benefit, when the main room is set to away, all other rooms will turn off, but can be manually turned back on. Grand total = $1,460Caleo image
  3. 1 Casa Connect Caleo Thermostat   with Built in relays, $130 and installation in less than 1 hour for $65, that’s a Grand Total of $195
    per room, or $780 for the whole home
    . The Casa thermostat will chat with its siblings, and now with IFTTT, can be adjusted via web portal or Android App only, and currently does not have any support for IoT integration, so it’s a stand alone system that doesn’t have the Smart characteristic, i.e. can’t use and share sensor data, yet. Also being a new device on the market, a track record of reliability still needs to be set. But keep an eye on this one. Did we mention they are made in Canada.
  4. 1 Mysa smart thermostat with Built in relay, $100 and installation in way less than 1 hour for $65, that’s a Grand Total of $165
    per room, or $660 for the whole home, really only going to cost about $530, because installing these units and connecting them is well under 1 hour each. The Mysa is Wifi enabled, comes with a very functional app, and includes geofencing, so It can set to an eco mode when you leave, and back on when you return home. The Unit also works with Siri, Amazon Echo and Google Home, and they are working on an IFTTT channel.  They certainly look nice in frosted white, this is another bonus. These units are also made in Canada. Thx Zachary.
  5. There is always the option to do nothing, and it was decided that at this time, to take this option. Think about what you want from your technology, then rationalize the cost vs benefit. In the end, will you meet the needs you are seeking for the cost. And also consider options to spending that money, perhaps changing habits, like remembering to turn down/off the thermostat/lights when you leave.

Pictured up top, are 3 thermostats, the Nest Smart Learning Thermostat, the Ecobee 3, and the Honeywell Wifi Smart Thermostat RTH9580wf1013/w. Each of these can be used in place of the Nest in the above scenarios, and the Honeywell isn’t quite as feature packed as the Ecobee 3 or Nest, its going for around $220, so that saves you $80 per unit. Nest recently announced the Nest E, $100 cheaper and supports up to 3 heat/cool modes which cover 95% of consumer needs, so it’s bringing the costs down, I’ve updated the math above using the new Nest E.



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