Heating water with electricity? Here's how to double the efficiency of a standard electric heat pump water heater, with a pretty simple installation. In this video Matt Risinger shows how to install a Rheem HP-50 water heater that is twice as efficient as a standard unit.In this installation, which takes place at a lake house where in the summer there is high hot-water demand given the number of guests, there are actually two units used. A lowboy hot water heater is used when there is more demand for hot water when guests arrive. The highly-efficient Rheem is used as a primary unit. The total number of gallons of hot water available to the house between the two units is 90 gallons. Logistically, Risinger explains how, given the second unit was not in the original plans, it was effectively added. He also provides cautionary hints as to installing to avoid any future water damage due to condensation.Finally, installation is one thing, but Risinger shows how the operation should be set up within the home to take advantage of the two units and how to opt for one, both, or no units at the flick of a switch. If you're heating water with electricity and you have period of high-load demand for hot water, watch this video and see how easy it is to install and use greater efficiency.