I used a cheap temp sensor to link the on of with the temperature further away in the room. Its more useful with space heaters it the winter.
Running it for 20 mins every hour during daytime is an interesting approach, id think it would be more effecive to do on 10 evey half hour but i suppose its really just a personal preference.
Have you done any measurements to see how effective it is 20mins every hour compares to every other hour?
The EFF maybe, but the USAs lack of a GDPR equivalent makes it harder.