Maybe so, theoretically--but practically, when I run the slide with 60 degree tap water during a 3 or 4 hour swimming session, it drops the temp of the pool very substantially, where we don't really notice a cooling difference from the evaporation. Maybe it's because the humidity is usually high 80's-100% most of the time. Dunno....I just know that by mid August or so, the kids are complaining because it's too hot to swim!

Janet