Heat Pump Water Heaters are a new concept! It works like an AC but instead of dumping heat outdoors, it puts it into the water. In addition, it blows cool air out and cools the space in the surrounding area of the tank.
The amount of electrical energy needed to create hot water is greatly reduced, it extracts up to 80% of energy from the ambient air around the unit. So, place it in the warmest spot you can to get the greatest efficiency!