Emerson Sensi ST55
Score: 72/100
Google Nest Thermostat
Score: 76/100Rankings
The Google Nest Thermostat offers Wi-Fi and Bluetooth connectivity with a compact 2.4-inch display and Energy Star efficiency. Its main trade-off is occasional C-wire requirement and a modest display size. Ideal for users seeking an affordable, Google-centric smart thermostat.
Emerson Sensi ST55 provides a 5-inch LED touchscreen, broad smart-home compatibility, and geofencing-driven energy savings, all at an affordable price. Limitations include the need for a C-wire, 2.4 GHz-only Wi-Fi, and lack of built-in room sensors. Ideal for DIY homeowners seeking a versatile, budget-friendly thermostat.
| Attribute | | |
|---|---|---|
3 yearsbest | 1 years | |
5 inchbest | 2.4 inch | |
| ↓ lower better | 0.386 kg | 0.139 kgbest |
Click an attribute name to sort · Green = best, red = worst (relative to this comparison)
| Attribute | | |
|---|---|---|
General(2) | ||
HVAC Compatibility | Various (single to multi-stage) | Supports heating stages W1-W3, cooling stages Y1-Y2, heat pump with auxiliary and emergency heat (O/B, AUX, E) |
Warranty (years) | 3 years | 1 years |
Connectivity(2) | ||
Wi‑Fi Standard | 802.11 a/b/g/n (2.4GHz) | 802.11b/g/n, 802.11a/n |
Smart Home Integration | Alexa, Google Assistant, Apple HomeKit, Samsung SmartThings | Google Home |
Power & Installation(2) | ||
C‑Wire Requirement | true | false |
Power Source | 20-30 VAC | HVAC system wiring |
Display(2) | ||
Display Type | LED touchscreen | IPS LCD |
Screen Size (inch) | 5 inch | 2.4 inch |
Build & Design(2) | ||
Device Weight (kg) | 0.386 kg | 0.139 kg |
Device Dimensions (H×W×D) (mm) | 25.4×149.35×95.25 mm mm | 27.2x84.0x27.3 mm |
Products in the top-left offer the best value (high score, low price).
Professional reviewers commend the Sensi ST55 for its straightforward DIY installation, ENERGY STAR efficiency and the claimed 23% energy savings, as well as its compliance with Title 24 and robust smart-home integration. However, they point out the need for a c-wire to unlock full functionality and the limitation to a 2.4 GHz Wi-Fi band.
Homeowners and renters alike praise the thermostat's quick setup, remote app control, energy-saving reports, and reliable fan circulation. Recurring complaints focus on occasional Wi-Fi drops, the necessity of a c-wire for some systems, and the lack of a built-in room sensor or precise humidity control.
