Bottom line: The Honeywell Home RTH9585WF is the smart thermostat to buy if you want a trusted HVAC brand, a genuinely easy DIY install, and a customizable color touchscreen — it’s held a 4.3-star average across more than 20,000 ratings, one of the largest review counts of any WiFi thermostat on Amazon.
Why We Picked the Honeywell Home RTH9585WF
Honeywell has been in the HVAC controls business for generations, and the RTH9585WF is built around the thing most first-time smart thermostat buyers actually want: a straightforward, self-installable upgrade from a traditional thermostat rather than a full smart-home overhaul. It has a customizable color touchscreen you can tint to match your décor, flexible 7-day programming, and it pairs with Alexa and Google Assistant for voice control once connected to WiFi. It’s also Energy Star certified, with monthly energy reports and personalized tips through the Honeywell Home app, and some utility providers offer rebates for buying it.
What Owners Actually Say
Ease of installation is the single most repeated compliment in the reviews. Multiple verified buyers describe swapping out an old thermostat in well under an hour using the same wiring, with one reviewer specifically praising the step-by-step installation video as “very clear and helpful” during a replacement of a 2-3 year old Nest-style thermostat. Owners with heat pump systems report accurate, steady temperature control — one buyer running a 2-stage heat pump in Florida said it “keeps a constant temperature at exactly what I set it to,” a notable upgrade from their previous thermostat. The screen readability also comes up often: one reviewer called the display “huge” and said they “can read it across the room in the dark.” Alexa integration gets consistent praise too, with several owners specifically mentioning voice-controlling the temperature from bed.
One Thing to Check
The most detailed and consistent caveat in the reviews is about Honeywell’s cloud service, not the thermostat hardware itself. A handful of long-term owners describe periods where remote app control becomes unreliable — commands queue instead of executing immediately, or the app reports a setting that hasn’t actually reached the thermostat — during what appear to be periodic server-side outages. This doesn’t affect manual, at-the-thermostat operation, but it’s worth knowing about if you plan to lean heavily on remote scheduling. Also worth confirming before you buy: this model requires a C-wire and does not work with electric baseboard heat (120-240V) — Honeywell’s listing includes a compatibility checker, and it’s worth using it before purchase if you’re unsure what system you have.
Pros
- Genuinely easy DIY installation, even as a like-for-like replacement
- Customizable color touchscreen display, readable across a room
- Works with Alexa and Google Assistant for voice control
- Energy Star certified with monthly usage reports and possible utility rebates
- Accurate temperature holding reported across both forced-air and heat pump systems
Cons
- Requires a C-wire; not compatible with electric baseboard heat (120-240V)
- A minority of long-term owners report Honeywell’s cloud/remote service having periodic outages
- Requires roughly a 3-degree gap between heat and cool setpoints, which can feel restrictive in shoulder-season weather
FAQ
Do I need a C-wire to install this thermostat?
Yes, a C-wire is required. Honeywell provides a compatibility checker and wire-identification guide on the product listing to help you confirm your system has one before buying.
Will it work with my heat pump?
It’s compatible with forced air (gas, oil, or electric), hot water and steam systems, and heat pumps with electric backup — but not with electric baseboard heat (120-240V) heat pump setups.
Can I control it with Alexa or Google Assistant?
Yes, once it’s connected to WiFi and paired through the Honeywell Home app, it works with both Alexa and Google Assistant for voice commands.
For Specific Needs
Is it good for a rental or shared house where multiple people adjust the temperature?
Owners report the app makes it easy to set temporary or vacation holds that automatically revert to your normal schedule, which several reviewers specifically use when guests or roommates need a different temperature temporarily.
How reliable is it for remote/away-from-home control?
Most reviewers report reliable app control, but a documented minority describe Honeywell’s cloud service experiencing periodic outages that delay remote commands — worth knowing if you’re relying on it while traveling rather than testing it for the first time from another state.
Does the display work in a dark hallway or bedroom?
Yes — multiple reviewers specifically praise the screen’s brightness and readability “across the room” and “in the dark,” and the display color/brightness is also adjustable in settings.
Methodology
This recommendation is based on rigorous analysis of verified-purchase reviews and live Amazon listing data — including rating trends, review volume, and recurring themes across more than 20,000 ratings — cross-checked against the manufacturer’s own compatibility specifications and Energy Star certification. We did not physically test this exact unit ourselves.
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How We Built This Guide
Our process: this is a research-based pick, not a hands-on lab test. We aggregate verified-owner reviews, professional test data where available, and real discussion patterns from communities like Reddit, then flag every estimate as such in the guide above. We do not accept sponsored placements.
Last checked: August 25, 2026