Thrifty King insulates the water so well that you can make it through the winter without supplying heat in many areas, and it takes little electricity in those areas where the winter is severe. The water is completely surrounded by fully insulated polyethylene plastic – even the floats are insulated. In summer, the water is cooler and covered water protects against mosquitoes breeding, lowering the risk of spreading West Nile Virus. The covered water also keeps the water cooler and prevent water evaporation during dry months.