Very good quality product. Fits our Barbados hot tub perfectly. I think it certainly helps with speeding up the heating process as we managed an increase of 7’C in just over 2 hours. The water is also holding it’s temperature quite well too when we turn the heater off only losing 1’C over a couple of days. We use the tub all year round (in a summerhouse) so the real test will be in the winter months!