I live in Northern California and we rarely run the AC or Heat. A few times in Augest we will run the AC when we get home from work and in January and Febuary we run the Heater. Is it ok to install the Teak 3 inch hardwood without running the HVAC or heater in this case? Will I get large gaps when we do run the HVAC or Heater for this short time? The average humidity is 46% in the afternoon and 86% in the Morning. Here is a website that has the brakedown. http://www.cityrating.com/cityhumidity. ... Sacramento

your floor will move if you dont control the temp and r/h. Yes installing when the humidty is high you will get some cracks in the winter. I think cracks are the leeser of the two evils when you compare it to swelling.