Something to think about when using your pool next summer: According to the green living website www.greenyour.com, "pools evaporate water and heat at an uncommon rate. Not using a pool cover has been compared to heating a home with the doors and windows open, or to building a house without a roof." By using a cover, "pool-related energy costs will be much less -- by about 50 to 70 percent if you heat your pool." Not only is it costly to go without the cover, it can be a drain on the water supply and also release harmful chemicals into the environment. So cover up.