Will it work with your system?
Works well with
- Phone control and scheduling
- Systems the maker's checker confirms
Check first if you have
- Walls without a C wire, unless you add one
- Line-voltage baseboard heat
- Millivolt gas heaters
What it controls
The Sensi ST75 Smart Thermostat is a smart Wi-Fi thermostat. Systems, per the maker: Works with the HVAC equipment found in most homes.
On power, its maker says it needs a C wire (the listing: "Common wire (c-wire) is required"). What a C wire does.
The listing doesn't state heat pump support; if you have an O/B wire, confirm with the maker before ordering. Heat pump wiring.
Connectivity: Wi-Fi. It amazon Alexa, Apple HomeKit, Google Assistant, SmartThings, Vera.
Not sure of your wiring? The wiring checker reads your system from the terminal letters and checks it against this model's statements.
Also on the listing: dimensions of 1.17 in (D) x 5.63 in (W) x 3.2 in (H), a weight of 13.6 ounces and a lcd.
Warranty, per the listing: 3 years.
Compatibility and specs
These come from the maker's listing for this exact model; the source of each is marked. Anything the maker leaves out is marked not stated.
| Model number | ST75 | Retailer |
|---|---|---|
| Model name | Sensi Touch | Retailer |
| Dimensions (seller) | 1.17"D x 5.63"W x 3.2"H | Retailer |
| Works with | Amazon Alexa, Apple HomeKit, Google Assistant, SmartThings, Vera | Retailer |
| Features (seller) | Auto Changeover, Daylight Savings Time Ready, Filter Indicator, Geofence Technology, Programmable | Retailer |
| Connectivity | Wi-Fi | Retailer |
| Power | AC/DC | Retailer |
| Voltage | 30 V | Retailer |
| Display | LCD | Retailer |
| Mounting / installation | Wall Mount | Retailer |
| Batteries | AA batteries required. | Retailer |
| Material | Plastic | Retailer |
| Warranty | 3 years. | Retailer |
| Product weight | 13.6 ounces | Retailer |
| C-wire | Common wire (c-wire) is required | Retailer |
| Works with systems | Works with the HVAC equipment found in most homes | Retailer |
Strong points and weak points
Strong points
- Works with Amazon Alexa, Apple HomeKit, G
Weak points
- Needs a C wire (maker)
- Needs Wi-Fi for smart features
Wiring and install notes
- Compatibility statements are the maker's own. Confirm with the maker's compatibility checker, turn the power off before wiring, and leave line-voltage and furnace work to a licensed electrician or HVAC technician.
Thermostats to compare it with
FAQ
Does the Sensi ST75 Smart Thermostat need a C wire?
Does the Sensi ST75 Smart Thermostat work with a heat pump?
Other smart thermostats with similar wiring
- Vine TJ-919T Smart Thermostat
- LUX TX500E Smart Thermostat
- ecobee EB-STATE7-01 Smart Thermostat
- Honeywell Home TH6220WF2006 Smart Thermostat
All smart thermostats in one grid · Every Sensi control listed
Our take
A fit for phone control and scheduling.
Where to get it
The link goes to this exact model's listing. Check that the box includes the trim plate or C-wire adapter you need, and confirm your wiring with the maker's compatibility checker before you order.
Each button opens this exact model. We may earn a commission on tracked links; it never changes what we publish. Disclosure