Honeywell Home X2S Smart Wi-Fi Thermostat RTH2SMC/N (White)

What the X2S is and which version this listing sells

The X2S is a Honeywell Home Wi-Fi thermostat made by Resideo and controlled remotely through the First Alert app. This listing's model number is RTH2SMC/N. Honeywell's product page shows the X2S under SKU RTH2CWF/U, and the listing-supplied installation guide covers three model numbers together: RTH2CWF, RTHC2CWF and RTH2SMC, so this listing's model is named in the maker's guide.

The guide lists the package as the thermostat, the UWP mounting system, screws and anchors, literature with wire labels, and a replacement accent piece. The listing names the included decorative accent pieces as white and gray. Honeywell's product page gives the thermostat's dimensions as 3.44 x 5.13 x 1.188 inches.

C wire, voltage and Wi-Fi requirements

Honeywell's product page and the listing both state that a C wire is required at 24 VAC. The guide says the thermostat will not work with a 120/240 V line voltage system, and describes the signs of one: thick black wires with wire nuts, or an existing thermostat rated 120 V or more. Honeywell and the listing also exclude electric baseboard heat at 120-240 V.

The guide says S and U terminals are not supported, and that if your old thermostat has wires on terminals the guide does not list, extra support is needed. Honeywell and the listing give Wi-Fi as 2.4 or 5 GHz, 802.11 b/g/n. We do not reproduce wiring steps here; follow the guide or a qualified installer.

Heat pump owners: read the stage limits first

Honeywell lists up to 2 heat and 2 cool stages on conventional systems and up to 2 heat and 1 cool on heat pumps; the listing adds that the heat pump figure applies with electric backup, and names hot water and forced air systems. The guide's installer setup is more specific: for heat pumps only one compressor stage is supported, with backup heat stages of zero or one.

The guide is also explicit that this thermostat only supports electric backup heat on a heat pump. If your heat pump uses a gas or oil backup heat source, the guide says the X2S should not be used. Check what backup heat your heat pump has before buying rather than after.

The guide warns that choosing the wrong heating system type means the thermostat will not operate as intended. It also advises against auto changeover if outdoor temperatures are often below 50°F in winter. Both settings sit in the installer setup, which the guide covers in full.

Scheduling, geofencing and what works without Wi-Fi

Scheduling options in the guide are one week with every day the same, each day separate, Monday to Friday plus Saturday and Sunday, or Monday to Friday plus the weekend, each with four periods a day; the listing adds a non-programmable option, and Honeywell's page lists 7-day, 5-1-1, 5-2 and 1 week. The guide also describes Auto Away based on your phone's location, smart scheduling and Smart Response.

The guide's FAQ says the thermostat works without Wi-Fi at the thermostat itself, but geofencing and some other features work only through the First Alert app. It also says everyone given access in the app shares the same privileges, so decide who to invite before sharing control.

The listing and Honeywell's page say the X2S is Matter certified and works with Amazon Alexa, Google Assistant and Apple Home. A separate Matter QR supplement is linked on Honeywell's page; we did not read it.

Settings that matter day to day

The guide lists a minimum heat setpoint adjustable from 32°F to 50°F with a 40°F default, and warns not to set it below 40°F unless pipes are not at risk of freezing. Setpoint ranges are 32°F to 90°F for heat and 50°F to 99°F for cool. Fan modes are Auto, On and Circulate, which runs the fan about 33 percent of the time.

Filter reminders can be set by equipment run time, from 10 to 150 run-time days, or by calendar time from 30 days to 15 months. Outdoor temperature and humidity appear only once the thermostat is registered. The guide lists numbered alert codes, and Honeywell's page names heat pump failure and filter change among its alerts.

Warranty

The guide states a 2-year limited warranty and sends you to honeywellhome.com/support for the warranty terms. Honeywell's product page lists the warranty as 2 years limited, and the listing's features bullet also says 2-year warranty, so all three sources agree on the length.

We did not read the full written warranty terms, so check them before relying on details such as who pays for removal or reinstallation. The guide lists Resideo support at 1-800-633-3991, including for problems with the account activation email sent during app setup.