No, you cannot. The Honeywell Home T9 is not compatible with line-voltage electric baseboard heat.
It is incompatible with two specific system types:
- Electric baseboard heat (120-240V).
- Millivolt systems.
The T9 is designed for low-voltage (24V) systems only, which include most central forced-air furnaces, air conditioners, and heat pumps. Line voltage systems use thick black wires, often with wire nuts, and carry 120V or higher. If your old thermostat has thick wires or wire nuts, it's a line-voltage system.
If you have a line-voltage system: Do not attempt installation. Your system is not compatible. You can call 1-855-733-5465 to find a professional installer who can recommend a suitable thermostat for your baseboard heaters.
Safety note: Attempting to install this thermostat on a high-voltage system can cause electrical shock, equipment damage, or fire.