The TruTankless electric tankless water heater squeezes 24 feet of heating element into a briefcase-size housing, which means it can heat water at a relatively low element temperature (500 degrees F versus 1,000 degrees F for some other models). That, along with the mineral-resistant alloy used to make the element, helps prevent the scale buildup that’s common with tankless. It also includes Wi-Fi functionality to alert the homeowner and plumber if problems develop. Several models are available, the most popular being a 4-gpm system sized for a three-bath home, which lists for $1,500. Bollente Cos., 855.862.8987, trutankless.com