
Emerson Sensi ST55
Score: 72/100
Honeywell Home RTH9600WF
Score: 78/100Rankings

The Honeywell Home RTH9600WF is an ENERGY STAR-certified smart thermostat featuring a vibrant color touchscreen and extensive smart-home integration. Its requirement for a dedicated C-wire and incompatibility with certain heating systems limit installation flexibility. Ideal for homeowners with compatible 24 VAC systems seeking advanced display and remote control.

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 | 2 years | |
5 inchbest | — | |
| ↓ lower better | 0.386 kg | 0.318 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) | Works with 24 VAC systems (forced air, heat pump, hydronic, hot water, steam); requires C-wire; incompatible with millivolt, 120/240V baseboard heat, heating-only oil furnaces without C-wire |
Warranty (years) | 3 years | 2 years |
Connectivity(1) | ||
Smart Home Integration | Alexa, Google Assistant, Apple HomeKit, Samsung SmartThings | Amazon Alexa, Google Assistant, IFTTT, iOS, Android |
Power & Installation(1) | ||
Power Source | 20-30 VAC | Battery |
Display(1) | ||
Display Type | LED touchscreen | LCD color touchscreen with backlight |
Build & Design(2) | ||
Device Weight (kg) | 0.386 kg | 0.318 kg |
Device Dimensions (H×W×D) (mm) | 25.4×149.35×95.25 mm mm | 89x22x114 mm 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.




Professional reviewers such as Consumer Reports evaluate the RTH9600WF on smart-feature performance (Smart IQ), manual operation ease, and automation capabilities, but detailed ratings are behind a subscription wall, leaving only a general acknowledgment of its comprehensive smart-thermostat functionality.