A standard tankless water heater replacement takes 4–6 hours when existing gas lines and electrical connections are already in place, though the timeline can vary based on your home's current setup and the specific unit being installed.
The replacement process begins with a thorough inspection of your existing plumbing, gas lines, and electrical infrastructure. Our technicians assess whether your current venting system, gas line sizing, and electrical capacity can support the new tankless unit or if upgrades are necessary. This diagnostic phase typically takes 30–45 minutes and is critical because undersized gas lines or inadequate electrical service can extend the project timeline significantly.
Once we've confirmed compatibility, the old water heater is disconnected from its gas supply, water lines, and venting system. Draining the tank and removing mounting hardware usually takes another 45 minutes to an hour. We then disconnect the old unit carefully to avoid damage to surrounding plumbing and drywall.
The new tankless unit installation involves several key steps. First, we mount the new heater securely to the wall using appropriate brackets—most modern units like Noritz or Generac models we're authorized to install require specific mounting hardware to ensure proper operation and warranty compliance. Next, we connect the cold water inlet and hot water outlet using appropriate fittings and sealant, then run new gas line connections if the existing line requires upsizing. For electrical models or hybrid units, we verify circuit capacity and install dedicated breakers as needed.
Venting represents another critical component. Depending on your unit type and home configuration, we'll install either direct-vent PVC piping (most common for tankless systems) or connect to existing venting. This step alone can take 1–2 hours if modifications to exterior walls or roof penetrations are needed.
After installation, we perform a complete pressure test on all gas and water connections, verify proper water temperature and flow, check venting for leaks, and test all safety features. This quality assurance phase ensures your new system operates at peak efficiency and meets local plumbing codes.
If your existing infrastructure requires upgrades—such as gas line replacement, electrical panel work, or venting modifications—the project can extend to 8–10 hours or even require a second visit. We always provide a detailed estimate upfront so there are no surprises about timeline or cost.
Our team arrives with the fittings, connectors, mounting hardware, and venting materials most jobs require, which means we typically complete the work the same day without unnecessary delays.
Blackmon Plumbing, licensed (MPL-38162) and an authorized Noritz and Generac dealer with 19 years of experience, provides professional tankless water heater replacement throughout the service area with upfront pricing and same-day installation availability.