variable drive

Designing watershapes of any sort is becoming more and more challenging every day.   Where not all that long ago consumers were happy if a pool or spa or fountain or pond simply looked good and operated reliably, there's a new generation of consumers who are much more interested in how these vessels are built and, more specifically, in knowing about how energy efficient they are. This trend is being driven on the one hand by the inevitability of rising utility rates and on the other by legislation such as California's Appliance Efficiency Code (Title 20) - a rule that's attracting the attention of code writers across the country because of the overwhelming importance these days of reducing energy consumption.     With that backdrop, this article takes a look at a watershape's main energy consumer and the most basic of all its