Sensi Smart Thermostat
$75.00
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4.9 out of 5 from verified customer reviews Read reviews →Description
The ST55U — Sensi Smart Thermostat — is stocked and shipped by Buy Comfort Direct from Winder, Georgia. Specifications, fitment notes and ordering details are below; call (877) 843-4822 if you need it matched to your equipment first.
About the ST55U
SENSI SMART WI-FI THERMOSTAT – ST55U
The Sensi ST55U Smart Wi-Fi Thermostat is an award-winning, ENERGY STAR®-certified thermostat backed by over 100 years of HVAC experience. Designed with a traditional footprint for drop-in replacement, it offers easy DIY installation, flexible scheduling, geofencing, humidity monitoring, and seamless smart home integration — all without requiring a common wire on most systems.
Wi-Fi & App Control
Manage your home comfort from anywhere using the top-rated Sensi app on iOS or Android.
Voice Assistant Ready
Works with Amazon Alexa, Google Assistant, and Samsung SmartThings for hands-free control.
Geofencing & Scheduling
Uses your smartphone’s location to auto-adjust temperature; set a unique schedule for every day of the week.
Humidity Monitoring
Built-in humidity sensing displays indoor conditions on-screen and in the app for improved air quality awareness.
Technical Specifications
| Specification | Value |
|---|---|
| Display | 5″ LED (backlit) |
| Connectivity | Wi-Fi 802.11b/g/n @ 2.4 GHz |
| Dimensions (H × W × D) | 3.75″ × 5.88″ × 1.00″ |
| Temperature Range | 50°F–99°F (set-point) / 32°F–99°F (display) |
| Power | 2 AA batteries or wired (20–30 VAC) |
| C-Wire Required | Not required for most systems |
| Certifications | ENERGY STAR® Certified, FCC |
| Warranty | 3-year limited warranty |
Performance & Reliability
The Sensi ST55U simplifies comfort management with smart alerts that notify you of HVAC issues before they become costly problems. Energy usage reports and geofencing help customers save approximately 23% on HVAC energy bills. The traditional thermostat footprint means no patching or painting — just a clean, straightforward swap for any existing thermostat.
Easy DIY Installation
Most installations complete in 30 minutes or less. Download the Sensi app and follow the step-by-step guided setup — no electrician required for most residential systems.
ST55U: fitment and resources
Match the part to your equipment by model number — if the listing does not answer a question, call before you order. Background reading: the U.S. Department of Energy maintenance guide. Browse the rest of our HVAC Parts & Supplies, and see what customers say on our reviews page.
Ordering and delivery
In-stock items ship from our Winder, Georgia warehouse; orders over $99 ship free. Large equipment travels by freight carrier and parts by ground, with tracking by email. Financing is available at checkout through Affirm, and contractors can set up a contractor account for trade pricing. Questions before you pay? Use the contact page or call (877) 843-4822.
ST55U FAQ
Does the ST55U ship free?
Yes on orders over $99 — most orders that include it qualify.
How do I know it fits my system?
Send us your equipment model number through the contact page or call (877) 843-4822 and we will confirm the match before it ships.
Additional information
| Weight | 1.00 lbs |
|---|---|
| Dimensions | 2.00 × 6.00 × 5.00 in |
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