When considering going tankless, it’s important to understand how many units you will need to provide hot water for your household. The number of tankless water heaters required is dependent on the total BTU (British Thermal Unit) rating of all appliances and devices that use heated water, as well as the desired temperature rise at the hot water outlet. For residential water heating applications, a single electric or natural gas tankless water heater with an appropriate BTU rating should be able to provide enough hot water for most households. Of course, if you have multiple bathrooms, a larger homes or large appliances such as washers and dishwashers that require a higher output of potable hot water, you may need additional units in order to keep up with demand. Be sure to check with a qualified installer and read any limited warranty information available on electric tankless water heaters before making your final decision.