Need device to measure power for an attic fan

Can someone recommend a device that will measure the power of an attic fan? In other words, I need to see if the fan is on. This fan goes on by temperature in the attic, so there is only an On/Off safety switch.

Replace the switch with an Inovelli on/off Red or Blue (coming) series. They have the ability to measure the current power consumption. Make sure that your fan does not exceed the switch’s rating.

These only go up to 300w. I found this: ENERWAVE Z-Wave Plus Switch, Z-Wave Switch, Smart Light Switch with Smart Meter Z-Wave Energy Monitor, Neutral Wire Required, Works with Alexa, Interchangeable Face Cover, ZW15SM-PLUS, White.

  • Neutral wire required. 120VAC; Incandescent: 1000W, Ballast: 1200VA, Resistive: 1800W (15A), Motor: 1/2HP; Enable 3-way/multi-location control with ZW3K-N Add-On Switch; Wall plate is not included; Z-Wave Plus certified, UL-Listed