Here is another odd way but could work really well for you because this is using an On-Off switch rated at 16amps with temp/humid sensor input capability so you could use it for maybe controlling the hot tub pump or heater controller as well.
Sonoff TH with using a DS18B20 temp sensor would be another alternative to consider. Doesn’t use batteries, very inexpensive. It does require you to flash the firmware for a simple custom add-on for gaining an On-Off control plus monitoring of temperature and humidity. You can get them on Amazon but I put the link to a manufacturer website for the full specs all on one page.
