Will it work with your system?
Works well with
- Gas fireplaces and wall furnaces
- Furnace and central air systems
Check first if you have
- Phone or voice control
- Line-voltage baseboard heat
What it controls
The Honeywell Home CT33A1009/N Millivolt Thermostat is a millivolt. Its listing doesn't spell out which heating and cooling systems it supports, so run the maker's compatibility checker before you buy.
It's listed for millivolt systems: the pilot-powered gas valves on fireplaces, wall furnaces and floor furnaces that a 24-volt thermostat can't switch. How millivolt systems work.
On power, the listing doesn't say whether it needs a C wire. What a C wire does.
The listing doesn't state heat pump support; if you have an O/B wire, confirm with the maker before ordering. Heat pump wiring.
Schedule: Non-Programmable. Program sleep and away setbacks once and it runs them every week.
Power, per the listing: 750 mV.
Not sure of your wiring? The wiring checker reads your system from the terminal letters and checks it against this model's statements.
Also on the listing: dimensions of 0.88 in (D) x 3.12 in (W) x 3.12 in (H), a weight of 2.4 ounces and a digital.
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 | CT33A1009/N | Retailer |
|---|---|---|
| Model name | CT33A Economy Millivolt | Retailer |
| Dimensions (seller) | 0.88"D x 3.12"W x 3.12"H | Retailer |
| Works with | Hand Control | Retailer |
| Features (seller) | Low Voltage | Retailer |
| Connectivity | Wired | Retailer |
| Power | 750 mV | Retailer |
| Voltage | 750 Millivolts | Retailer |
| Display | Digital | Retailer |
| Mounting / installation | Wall Mount | Retailer |
| Material | Plastic | Retailer |
| Product weight | 2.4 ounces | Retailer |
| Schedule | Non-Programmable | Retailer |
Strong points and weak points
Strong points
- Non-Programmable
- Power: 750 mV
- No Wi-Fi or account needed
- Millivolt-rated
Weak points
- No remote control
- Systems not stated
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 CT33A1009/N Millivolt Thermostat need a C wire?
What systems does the Honeywell Home CT33A1009/N Millivolt Thermostat work with?
Other programmable and basic thermostats with similar wiring
- Honeywell Home CT30A1005 Non-Programmable Thermostat
- Heagstat H701 Non-Programmable Thermostat
- Riseem S3001-White Non-Programmable Thermostat
- Riseem STN601-Blue Non-Programmable Thermostat
All programmable and basic thermostats in one grid · Every Honeywell Home control listed
Our take
A fit for gas fireplaces and wall furnaces.
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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