Does a tankless water heater make more sense than a solar water heater?
We don’t think so. The water you use still has to be heated: The amount of energy required to heat a gallon of water to a certain temperature does not change just because it is being heated at a faster rate. The tankless water heater only eliminates energy costs for maintaining the temperature of water that has been heated and is sitting in the storage tank awaiting use. So a tankless water heater is only about 15 to 20 percent less expensive to operate than a conventional electric or gas water heater. And tankless water heaters do have drawbacks. According to the U.S. Department of Energy, “Sometimes … even the largest, gas-fired model cannot supply enough hot water for simultaneous, multiple uses … taking a shower and running the dishwasher at the same time can stretch a (tankless) water heater to its limit.” Or you can install a solar water heater. Solar water heating systems can provide all the benefits of tankless water heaters but eliminate up to 90 percent of your water heating
