The short answer is YES, you can wire multiple heaters to one thermostat, but it depends on several factors to ensure your circuit can handle the load. See full Tech Article for more detailed info. IMPORTANT: The number of heaters you can connect to one thermostat depends on your circuit size and wiring
Installation
If I need to replace my heater, can I use a higher wattage heater?
Your electrical system was sized for the original heater’s wattage. A smaller heater would be OK, but a larger heater may create a hazard.
Why does my new heater produce smoke when I turn it on?
In the manufacturing process, a light lubricant is used, which will burn when the heater is energized. The smoke will stop after the heater has fully heated. There is no cause for alarm. It is recommended to open a window during initial operations.
My thermostat is above my fan-heater. Why?
The fan heater blows warm air away from itself and into the room. By the time the warm air has recirculated and reached the thermostat above the heater, a comfortable room temperature has been achieved.
My baseboards are on outside walls, should fan heaters be also?
No. A fan heater, recessed into an outside wall, will create extra heat loss and air leakage for that room. An inside wall, facing a cold window, is the best location.