Will it work with your system?
Works well with
- A weekly schedule without an app
- Older wiring without a C wire
Check first if you have
- Phone or voice control
- Line-voltage baseboard heat
What it controls
The Honeywell Home RTH20B Programmable Thermostat is a programmable. Its listing doesn't spell out which heating and cooling systems it supports, so run the maker's compatibility checker before you buy.
Check your wall for a C terminal: its maker says no C wire is needed ("Battery powered (2 AA) (not included) — no C-wire required"). The C wire guide covers adapters.
The listing doesn't state heat pump support; if you have an O/B wire, confirm with the maker before ordering. Heat pump wiring.
Stages, per the maker: 1 Heat/1 Cool. Compare that with the W2 and Y2 wires at your wall. Reading stages from your wires.
Schedule: non-programmable. A schedule only saves energy if it's set; spend five minutes on it after installing.
Power, per the listing: Battery Powered. Battery models often fit old two-wire circuits with no C wire.
Tick your terminals in the wiring checker to see whether its maker's statements cover your system.
Also on the listing: dimensions of 1.8 in (D) x 6.5 in (W) x 8.8 in (H) and a lcd.
Compatibility and specs
These come from the maker's listing for this exact model; the source of each is marked. Anything the maker leaves out is marked not stated.
| Model number | RTH20B | Retailer |
|---|---|---|
| Model name | RTH20B | Retailer |
| Dimensions (seller) | 1.8"D x 6.5"W x 8.8"H | Retailer |
| Works with | Push Button | Retailer |
| Features (seller) | special_feature | Retailer |
| Connectivity | Wired | Retailer |
| Power | Battery Powered | Retailer |
| Display | LCD | Retailer |
| Mounting / installation | Wall Mount | Retailer |
| Batteries | 2 AA batteries required. | Retailer |
| C-wire | Battery powered (2 AA) (not included) — no C-wire required | Retailer |
| Heat / cool stages | 1 Heat/1 Cool | Retailer |
| Schedule | non-programmable | Retailer |
| Voltage | 750 mV | Retailer |
Strong points and weak points
Strong points
- non-programmable
- Power: Battery Powered
- No Wi-Fi or account needed
Weak points
- No remote control
- Systems not stated
- Batteries to replace
Wiring and install notes
- Compatibility statements are the maker's own. Confirm with the maker's compatibility checker, turn the power off before wiring, and leave line-voltage and furnace work to a licensed electrician or HVAC technician.
Thermostats to compare it with
FAQ
Does the Honeywell Home RTH20B Programmable Thermostat need a C wire?
What systems does the Honeywell Home RTH20B Programmable Thermostat work with?
Other programmable and basic thermostats with similar wiring
- Honeywell Home RTH2300B1038 Programmable Thermostat
- Honeywell Home RTH2510B1018 Programmable Thermostat
- White-Rodgers 1F83C-11PR Programmable Thermostat
- LUX TX9600TS Programmable Thermostat
All programmable and basic thermostats in one grid · Every Honeywell Home control listed
Our take
Shortlist it for A weekly schedule without an app.
Where to get it
The link goes to this exact model's listing. Check that the box includes the trim plate or C-wire adapter you need, and confirm your wiring with the maker's compatibility checker before you order.
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