The cost of heating water consumes almost 20 percent of your household budget, second only to what you spend on heating and cooling your home. And if you’ve been spending more time at home ...

Tankless gas water heaters heat water using either a condensing or non-condensing method. The former usually has two heat exchangers while the latter has one, manufacturer Navien explains.

Korean manufacturer Navien goes one step further ... For example, if your current water heater is electric and you don't have natural gas or propane capability, a tankless model might not make ...

All their work now is done with tankless water heaters—exclusively Navien, and mainly the model NPE-240A ... system the company racks units together (normally at least six to a rack), all linked, ...