Why learn how to install a water heater yourself? Tankless water heater installation costs may be less than you think..The average cost to install a tankless water heater is $,. Homeowners find themselves spending between $ and $,, depending on the and factors like labor. The typical hourly rate for a plumber is $ $..Heating water amounts to nearly of a home’s energy costs. If you’re installing a new water heater or Our water heater installation pricing .There are a number of factors that play a part in the cost of installing a new water heater. Tank vs. Tankless. Average cost with installation Tank $. gallon tank Tankless $,. Water heaters come in two different styles tank and tankless. Both heat your water, but they do it in different ways..