How do I Install Mysa when I have multiple heaters in my room?

Danger: A qualified electrician should install high voltage equipment. Please ensure that you comply with local electrical codes and regulations. Improper installation can lead to device failure and even cause a fire. Damage to thermostat due to improper installation is not covered under warranty.

It is possible to wire multiple baseboard heaters to one Mysa, assuming the combined wattage is less than 3800 watts. For example, one Mysa can control:

  • Two 1500 watt heaters
  • Three 1000 watt heaters
  • Five 750 watt heaters

Typically, when you replace a thermostat with Mysa, the heaters will already be connected to that thermostat via one wire nut, therefore, replacing a thermostat with Mysa is as simple as finding the set of wires that are bundled together and then connecting Mysa's load wire to that bundle.



If the bundle of heater cables has already been separated, you'll have to electrically verify each wire. Reference the tables below to determine which wires are the Supply, Neutral, and Load wires.


240V Installations

Gang Box Wires Identification Voltages 
Second Phase Leg (L2) (240V)  Ground to L2 (120V)
Supply Wire (L1)  Ground to L1 (120V)
Load Wire   Ground to Load (0V)


120V Installations

Gang Box Wires Identification Voltages
Neutral Wire (N) Ground to N (0V)
Supply Wire (L1) Ground to L1 (120V)
Load Wire  Ground to Load (0V)