I am currently heating my attached garage with a 4KW electric workshop heater. I have tubing in the floor for radiant heat and I want to take advantage of radiant floor heat. Please note electricity is my only energy option.

I am thinking of installing a 6KW high-flow tankless WH as my heatsource, it is activated by flow. Am I correct to assume I could use a 120V thermostat to control my pumps to cycle the system? I am thinking it should work.

I have one zone with four loops of about 210 ft each. 1/2" pex.