How to Install a Tankless Water Heater

Water heaters are the silent workhorses of a home, and upgrading to a tankless system marks the end of the dreaded cold shower. Unlike bulky storage tanks, these units provide hot water on demand, saving space and eliminating the energy waste of keeping forty gallons of water hot all day long. A successful install relies on precise placement and ensuring your home's utility supply can handle the higher peak demand these units require. Done well, a tankless install looks clean, with all plumbing and venting tucked neatly against the wall. You aren't just saving space; you are optimizing your home's efficiency for the next decade. If you respect the requirements for gas pressure or electrical amperage, the system will reward you with endless hot water and lower utility bills.

  1. Empty the Old Tank First. Shut off the water supply to the home and drain your existing tank using a garden hose connected to the drain valve. Once empty, disconnect the gas or power lines and the plumbing connections before hauling the old unit out of the way.
  2. Anchor to Wall Studs. Position your mounting bracket on the wall studs, ensuring the unit is level and within the manufacturer's specified clearance distances from windows or vents. Secure the bracket with heavy-duty lag screws and hang the unit firmly in place.
  3. Connect Water Supply Lines. Install isolation valves on both the cold water inlet and the hot water outlet. Use flexible stainless steel water connectors to link your existing house plumbing to the unit, ensuring you include a pressure relief valve as required by local code.
  4. Route Exhaust Through Wall. Cut the necessary holes through the exterior wall for the intake and exhaust pipes using the manufacturer's template. Seal the penetrations with high-temperature silicone to prevent drafts and water intrusion.
  5. Test Gas Connections Thoroughly. Connect the gas line (or hardwire the electrical connection) according to the unit's manual. Use a dedicated gas shut-off valve and verify your pipe diameter is sufficient to handle the unit's high BTU output.
  6. Purge Air and Test. Open the water supply valves slowly, then turn on a hot water faucet at the nearest sink to purge air from the lines. Finally, power up the unit and check the display for any error codes before dialing in your preferred temperature.