Wattage & Amperage Limits
Last updated: August 11, 2026
Your heater's wattage must stay within these limits for Mysa for Baseboards to operate safely.
Wattage limits by voltage
Voltage | Maximum Wattage | Amperage | Recommended Breaker |
|---|---|---|---|
120V | 1900W | 16A | 20A |
240V | 3800W | 16A | 20A |
208V | 3300W | 16A | 20A |
These limits cover roughly 90% of homes.
Multiple heaters on one circuit
You can control multiple heaters with one Mysa thermostat if:
Total combined wattage is under the limit for your voltage (see table above)
Total amperage is under 16A
All heaters are on the same circuit
Add up the wattage of all heaters on the circuit to confirm you're within limits before buying.
Where to find your heater's wattage
Check the rating plate on the heater itself, usually stamped or printed on a metal label. If you can't find it, take a photo of the heater and your existing thermostat wiring and email install@getmysa.com — our team can help confirm.
Get Support
Email: install@getmysa.com