There are so many factors that determine the cost of a tankless water heater and they are as follows: 

1) Do you have existing gas? 
If you don't it will greatly increase the upfront cost of a tankless water heater. 

2) Is the water heater near an outside wall or roof? 
Since a gas tankless water heater must be vented, it makes for a less expensive job when the existing heater is near an outside wall or roof. 

3) Is the house on a crawl space? 
Houses in Myrtle Beach are sometimes on a crawl space and that makes installing a tankless water heater much easier as it can be located outside the house and tapped into the existing pipes. 

4)How many people live in the house? 
When a lot of people will be showering at the same time you will need a larger tankless Rinnai or Navien. If it's just 2 people living in the house a small, economical unit can be used. 

These 4 factors greatly effect the cost of a Tankless water heater in Myrtle Beach. 

​Hope that helps!