Smart thermostat guide
Honeywell Home T5 Smart Thermostat RTH8800WF2022
24 VAC systems with a C wire, up to 2 heat/2 cool, on a 2.4 GHz network
A Wi-Fi touchscreen thermostat with schedules, geofencing or manual control. Resideo's guide requires a C wire and lists no adapter in the box, and it excludes millivolt and baseboard systems. Wi-Fi is 2.4 GHz only. Up to 2 cool and 2 heat stages, plus 1 aux/emergency stage. Two-year warranty.
Listing checked . Confirm the model, included parts and availability before ordering.
Published specifications
- Guide: C wire (24 VAC) required; no adapter in the listed box contents
- Guide: up to 2 cool/compressor, 2 heat, 1 aux/E stage
- Guide: no baseboard (120-240 V), no millivolt, no S or U terminals
- Maker: Wi-Fi 802.11 b/g/n, 2.4 GHz only
- Maker and listing: 4.06 x 4.06 x 1.06 in; touchscreen; 5-2, 5-1-1, 7-day
- Guide and maker: 2-year limited warranty
Fit and limits
Strengths
- Temperature stays adjustable at the unit if Wi-Fi drops
- Guide spells out stages and excluded systems clearly
- Two-year warranty agreed by guide and maker page
Caveats
- C wire required and no adapter listed in the box
- 2.4 GHz Wi-Fi only
- Guide and maker page name different apps
Which T5 this is
The T5 Smart Thermostat is Honeywell Home's Wi-Fi touchscreen thermostat. This listing's title names model RTH8800WF2022, Honeywell's product page shows SKU RTH8800WF2022/U, and Resideo's quick install guide lists RTH8800WF2022 among the seven model numbers it covers. The listing and Honeywell's page both give the size as 4.06 by 4.06 by 1.06 inches.
The guide lists the box contents as the T5 thermostat, the UWP wall plate, screws and anchors, and the quick install guide. The guide's box list does not include a C-wire adapter, which matters for the next section; the listing also tells you to check whether your home needs one.
The C wire is required
The guide's compatibility page states that 24 VAC power by C wire is required. The listing puts it as C-wire power adapter required and tells you to check compatibility and whether your home needs an adapter before buying. It also says the thermostat will not work with heat-only oil furnace systems unless a C wire is present.
The guide says the T5 does not work with electric baseboard heat at 120-240 V or with millivolt systems, and does not support S terminals, or U terminals for ventilation. It is otherwise described as compatible with most heating, cooling and heat pump systems. We do not give wiring steps here.
Stages and system types
In the guide's equipment setup, system types are conventional, heat pump (including air-to-air and geothermal), boiler (hot water or steam) and cool only. It allows up to 2 cool or compressor stages, up to 2 heat stages, and 1 auxiliary or emergency heat stage at most on systems with more than one heating equipment type.
Honeywell's specification block on this page does not list stage counts, so the guide is the source here. Schedules can be set as every day the same, 5-1-1, 5-2, each day different or no schedule, with four periods a day; Honeywell's page lists the same programming choices.
Wi-Fi: 2.4 GHz only
Honeywell's page lists Wi-Fi as 802.11 b, g and n in the 2.4 GHz range, and its comparison grid also says 2.4 GHz. The guide's FAQ has an entry explaining that the thermostat works on 2.4 GHz only, so check that your router offers a 2.4 GHz network before you buy.
The guide's FAQ says the thermostat works without Wi-Fi at the thermostat itself, but geofencing works only through the app. It also has a section on a lost or offline Wi-Fi connection, and a manual setup option in case your network is not working at install time.
Which app, and who can control it
The 2025 quick install guide sets the thermostat up with the First Alert by Resideo app. Honeywell's product page, by contrast, says the T5 is supported by the Resideo app. Check which app the current guide in your box names before you start.
Honeywell's page lists Amazon Alexa, Google Assistant, Microsoft Cortana, Samsung SmartThings, IFTTT and Apple HomeKit, and the guide's back cover carries a HomeKit setup code. The guide's FAQ says everyone you give access shares the same privileges, and it has an entry on geofencing with several users.
Warranty
The quick install guide states a 2-year limited warranty and points to honeywellhome.com for warranty information. Honeywell's product page lists the warranty as 2 years, so both maker sources agree on the length.
We did not read the written warranty, so check it before relying on details such as removal or reinstallation costs. The guide lists Resideo support at 1-800-633-3991, including for problems with the account activation email.
Check the current listing
Confirm the model, included parts and availability before ordering.
Primary sources
- Honeywell Home T5 Smart Thermostat product page and specifications (SKU RTH8800WF2022/U)
- Resideo T5 Smart Thermostat Quick Install Guide 33-00363EFS-07
Primary sources checked .
Compare with
- Sensi Smart Thermostat ST55
Conventional or heat pump systems up to two stages, on a 2.4GHz network, in the old thermostat's footprint
- Google Nest Thermostat (Charcoal)
Single-stage 24V systems that need a schedule and app control, not multi-stage equipment
- Mysa Smart Thermostat V2 for Electric Baseboard Heaters (BB.2.0.01.NA-US)
120V or 240V electric baseboard, fan-forced convector and radiant ceiling heat in a standard gang box
- ecobee Smart Thermostat Premium with SmartSensor
24 VAC forced-air, heat pump, boiler or PTAC systems, checked first with ecobee's compatibility tool
- Google Nest Learning Thermostat (4th gen) with Nest Temperature Sensor (2nd gen)
Multi-stage 24V systems run through the Google Home app, in homes with or without a C wire
- ecobee Smart Thermostat Essential (EB-STATE7-01)
Simple single-transformer systems with one stage of cooling, on a 2.4GHz network
Side-by-side pages, this model next to: Honeywell Home T9 Smart Thermostat with 1 Room Sensor RCHT9610WFSW2003, Honeywell Home X2S Smart Wi-Fi Thermostat RTH2SMC/N (White).