Prebuy FAQ — Mysa for In-Floor Heating

Last updated: August 26, 2026

Common questions before buying Mysa for In-Floor Heating.

Will it work with my floor heating?

It works with electric radiant heating mats and cables on single-phase 120V, 208V, or 240V, within the load limits. It does not work with hydronic (hot water) floor heating, 24V systems, or three-phase 208V.

How much heating can it control?

  • 120V — up to 1,900W

  • 208V single-phase — up to 3,328W (16A)

  • 240V — up to 3,800W (15A)

Can one thermostat run several zones?

No. Each thermostat controls one compatible zone. Install one per zone and add them all to the same Mysa account. There is no Mysa power module.

Can it control my floor heating and a wall heater together?

No. That is not a supported installation, even if the combined wattage is under the maximum. Use Mysa for Baseboards for wall, baseboard, convector, or fan-forced heaters.

Do I need a new floor sensor?

A sensor is included — 10K Ohm at 25°C with a 15 ft (3 m) cable. If your floor already has a sensor from a previous thermostat, it will work as long as it is in the 5K to 40K Ohm range, and you can select its resistance in the app.

My circuit already has a GFCI breaker. Is that fine?

No. Mysa has a built-in Class A GFCI that cannot be disabled, and two GFCI devices conflict. An electrician needs to fit a standard breaker instead.

Will it damage my hardwood or vinyl floor?

Smart Limit Protection caps the floor temperature at your flooring manufacturer's recommended limit — 30°C (86°F) by default. You pick your floor type during setup.

Can I install it myself?

Only if the circuit is 120V on a single-pole breaker and you are experienced with line-voltage work. A 240V system requires a licensed electrician. See Do I Need an Electrician to Install Mysa for In-Floor Heating?

Does it work with my smart home?

Yes — Apple HomeKit, Google Home, and Amazon Alexa. The thermostat needs a 2.4 GHz Wi-Fi network.

Still not sure? Contact support@getmysa.com with your heating system voltage, wattage, and photos of the existing thermostat wiring.