Hybrid Water Heaters
This hybrid system captures heat from the air surrounding it and then transfers that heat to the water stored in its tank. They use about 60 percent less energy than your standard storage tank water heaters.When considering this system, it is good to know that it does not work as well in cold spaces. It is best in areas that stay a constant 40 to 90 degrees.
They also take up much more space than a normal system. They are extra tall because the heat pump sits on top of the tank, which means you need at least a 7-foot-high clearance, and they need up to 1,000 cubic feet of un-cooled space in order to capture enough air to heat the water. There also needs to be a nearby draining system to clear away the leftover from the condensation.
Solar Water Heaters
This system is one of the more popular options for energy efficiency. When you purchase a solar water heater, a solar panel is installed on your home's roof, which heats an antifreeze-like liquid located in an attached tank. This fluid then runs down a pipe through your home and around your tank to heat the water. Once it has transferred the heat, the fluid runs back up to the small tank on the roof to be heated once again.
Solar systems best work in areas that are sunny the majority of the time, but most systems also have a backup system that runs when needed.
This model is a great option if you need a tank over 55 gallons and heat with natural gas. A condensing water heater uses exhaust gasses to heat the water stored in the tank. Instead of the gasses escaping through the flue and wasting energy, they are captured and blown through the base of the tank where the heat is transferred to the stored water.