ntroducing the most energy efficient Heatbot-SZS-Mechanical water heater from A. O. Smith, the World's No. 1 manufacturer in water heaters. Build to be Smart . Build to be Beautiful. There are water heaters. And there are HeatBots. Future Ready, easy-to-use, eco-friendly and nothing short of masterpiece.BEE 5-star rated with Advanced PUF Technology for Power Savings. Perfect if you want to Go Green.