How Long Does It Take to Replace a Water Heater With a Tankless?

A gloved hand holds a level against brand-new black iron gas piping, a union and shutoff valves already threaded in. That gas work is a big reason this kind of swap takes longer: a tankless burner needs far more gas at once than a tank does, so the old line often isn't big enough.

A tech in a gray cap mounts the Navien on the wall and connects its piping while a second tech works overhead from a ladder. Every connection here is new, not a reconnect to the spot where the old tank sat.