Start with simultaneous hot-water use
List the fixtures you may run at once, such as showers, laundry, and kitchen use. Ask the contractor to explain the proposed unit’s flow capacity against that demand and the water temperature rise it must provide. A tankless unit’s flow rating differs from a storage unit’s tank volume or first-hour rating; ENERGY STAR explains the distinction.
Ask whether a storage replacement would meet the same need with a simpler scope. A tankless unit is not a promise of unlimited hot water at every simultaneous fixture.
What a tank-to-tankless conversion may involve
The contractor should inspect the existing fuel supply, electrical availability, water connections, location, and, for gas equipment, venting. The selected model determines which changes are needed; ENERGY STAR recommends an in-home check of these items.
Ask whether the proposal includes removing the storage tank, routing new connections or venting, and restoring any affected area. If the existing heater is in an attic or garage, ask how equipment access, placement, and future maintenance will work. Do not assume the current location suits the new unit.
- Proposed model, fuel source, and capacity basis
- Gas, electrical, water, venting, and condensate work where applicable
- Location and access, old-unit removal, and finish work
- Permit and inspection responsibility, exclusions, and written approval for changes
Compare two complete proposals
Request a storage replacement option if you want a meaningful comparison. Compare total work, maintenance requirements, written equipment and labor warranty terms, and what would be extra. Our replacement cost checklist can be used for both options.
We confirm service coverage with you before a visit. The plumber checks applicable requirements for the actual property. See what to prepare and send a request to our team.
Sources and useful checks
Guide updated . General planning information; the contractor must assess your property.