The cost of installing a tankless water heater can vary depending on several factors, including the size and type of unit, the complexity of the installation, and the location of the home. On average, the cost of installation can range from $2,000 to $4,500, including labor and materials. However, some high-end units and complex installations may cost more. It's important to consult with a licensed plumber to determine the best type and size of tankless water heater for a specific home and budget.