Sensi Smart Thermostat ST55

The Sensi ST55 ($129) is an affordable smart thermostat packed with useful features including support for geofencing, voice control via Amazon Alexa, Apple Siri, and Google Assistant, and support for the HomeKit and SmartThings home automation platforms. It’s easy to install and program, and it offers usage reports, local weather reports, and smart alerts. That said, it doesn’t integrate with quite as many third-party devices as our Editors’ Choice winner for affordable smart thermostats, the identically priced Nest Thermostat

Functionality Over Fashion

The ST55 eschews the stylish design that you get with its $169 sibling, the Sensi Touch Smart Thermostat ST75, and the sleek, puck-shaped Nest Thermostat. It’s a rather plain-looking device that sports a matte white finish and measures 3.7 by 5.8 by 1.0 inches (HWD).

In the center is a 1.7-by-2.7-inch (HW) monochrome LCD and below that are Mode, Fan, and Schedule buttons. Off to the right are up and down arrows and a Menu button, and there’s a light button on the top edge that illuminates the LCD. Use the Menu and arrow buttons to access thermostat settings where you can configure Wi-Fi, select a temperature mode (Celsius or Fahrenheit), configure cooling and heat pump settings, adjust fan speed, and configure humidification set points. 

Sensi Smart Thermostat ST55 installationIFTTT applets that would allow it to work with numerous third-party smart home devices.

The thermostat uses the same Android and iOS mobile app as the ST75. The home screen displays the current temperature and humidity, the local weather, and the current schedule. At the bottom of the screen are buttons for Mode (heat, cool, off), Fan (on, auto), Schedule, and Usage. The Schedule button takes you to a screen where you can create heating and cooling schedules and enable geofencing, and the Usage button opens a screen where you can view daily and monthly usage reports. 

Sensi app screens showing current temperature, thermostat settings, and system settings January 21, 2021

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