Themo is designed to be used with direct electric underfloor heating (maximum switching current of 12A). At the moment it is not possible to be used with hydronic (e.g water based) underfloor systems. Electric underfloor heating thermostats are usually powered by high voltage (220-240V) current and can be dangerous when dismantling.

If unsure of which type of underfloor heating you have, please consult with a professional.