I know with the time differentials this post may not show the correct time, but it is currently 12:40am hear in the midwest. I did my first drain and refill today (after 4 months) the water was still in good condition but thought today would be a good day. Temp's were at 39 degrees outside at 11:00 am, drained tub, did a quick wipe and clean, then had tub refilled around 3:00 pm put power back to tub after the fill the inside tub temp. was at 40 degrees, 6.5 hrs later the tub was at 105 degrees. I waited until 12:01 to go out and soak temp was at 108 degrees, just now getting back in from a great soak from what will be a 10 yr old tub after tommorrow so far a good investment but I'm sure next months power bill will show the 6 plus hours of the heater being on. Next drain and refill will be sometime in april!!!!!!