Background
A house has a handful of line voltage electric baseboard heaters (240V, 3600W).
Problem
Control the schedule and current temperature without connecting beyond a local area network.
Hard Requirements
- Supports Wi-Fi connectivity to local area network.
- Does not require Internet connectivity at any time.
- Thermostats can be uniquely referenced by name (or IP address).
- Encrypted transport protocol and password protected.
- Change the temperature from a terminal using REST over HTTP:
$ curl -d "thermostat=kitchen&set=20C&token=T" -X POST https://10.0.0.15/temp
Soft Requirements
Optional requirements include:
- Offers a simple web server (or Bluetooth for initial setup).
- Thermostats can be named.
Hub
If a hub exists that offers an open REST over HTTP API, then that would work. Preferably, the thermostats will operate standalone (without a hub).
Alternatives
Mozilla's Things Gateway looks promising as a way to connect to a hub. Benjamin Francis wrote,
My one suggestion would be to look for a Zigbee thermostat and then use the Things Gateway to bridge it to an IP network and expose a REST + WebSocket API. We already have a Zigbee adapter and would like to add support for a thermostat web thing type. I'd be interested to hear what you find because I'm looking for something similar for my own home. I was considering Honeywell.
Research
Here are a variety of contenders and reasons they don't work, as I've discovered or been told from sales representatives:
- Walker Technologies' Wireless Baseboard Thermostat - The WZ_LVS250 contains a built-in motion detector and requires Zigbee.
- Nuheat SIGNATURE Thermostat - Activating Wi-Fi states, "Enter an email address where an activation email may be sent."
- CALEO CASA Wi-Fi Thermostat - "I have Casa as well, but there is no APIs whatsoever (no integration with SmartThing possible)."
- Mysa Smart Thermostat - "Any local control we do implement will most likely not be via HTTP, and will be intended to be used from our app."
- STELPRO 4000 W KI Thermostat - Requires Z-Wave or Zigbee.
- ATMOZ-2-240-Wifi Programmable Line Voltage Thermostat - Reviews are less than stellar.
- Sinopé TH1121RF-4000 - "As the control and programming requires the GT125 to access the thermostats and that you need to be physically in front of the GT125... Also, as it is not wifi, you cannot connect directly to the device."
- Honeywell YTL9160AR1000/U - Seems to require "Cloud-based API for Wi-Fi Thermostats" or its RedLINK Internet Gateway.
There are a number of 24V thermostats that won't work, which include:
Question
What thermostats would permit controlling temperature via the command-line over Wi-Fi without Internet connectivity?
Alternatively, are there any absolutely silent 240V to 24V relays that would be perfectly safe to use with one of the typical 24V devices?