Replacing a water heater typically takes between 2 to 3 hours if there are no complications. This timeframe includes draining and disconnecting the old unit, removing it, positioning the new water heater, connecting it, and ensuring it meets safety standards

. Typical steps and time breakdown:

• Draining and disconnecting the old water heater: 45 to 60 minutes
• Removing the old unit and moving the new one into place: about 30 minutes
• Connecting the new water heater and testing it: 45 to 60 minutes

If you are switching from a tank water heater to a tankless model, the installation may take longer due to additional work such as installing new power lines, water lines, and air vents

. Replacing a tankless unit with another tankless typically takes 1 to 3 hours

. After installation, cleanup and removal of the old unit usually take an additional 30 minutes

. In summary, a standard water heater replacement can be done in about 2 to 3 hours, but more complex installations may extend the time to 3 to 4 hours or more depending on the type of heater and plumbing adjustments needed