Compare the equipment and hot-water need
Ask for the exact model, fuel, storage volume where applicable, venting type, dimensions, and the household needs used to choose it. Tell the provider about your busiest period of showers and other hot-water use, and whether the current heater meets it.
For a storage heater, tank gallons are only part of the comparison. DOE defines first-hour rating as the hot water it can supply during an hour that begins with a fully heated tank. Ask each bidder how the proposed model's rating fits your busy hour. That rating is not a promise that every household will get the same shower time. DOE explanation of first-hour rating.
For a tankless proposal, ask for the expected hot-water flow at the relevant incoming water temperature and your desired outlet temperature, with the supporting model data. Do not compare it with a tank using storage gallons alone.
Compare the whole installation
Request an itemized scope for removal and disposal, delivery and access, labor, water connections, venting or combustion-air work where relevant, electrical work where relevant, permits and inspections, and startup. Ask which code-related corrections are required at your actual home and why. Have the provider distinguish necessary work from an optional upgrade.
If another qualified provider owns electrical or building work, the proposal should name that responsibility and who coordinates it. Confirm whether finish repairs, concealed problems, and any allowances are included. Ask what could change the price and how you approve extra work.
Then compare written parts and labor coverage, payment terms, scheduling, and what records you receive. Treat rebates or other incentives as separate, unconfirmed items until the issuer confirms your exact installation. A lower net price based on an assumed rebate is not the same as a lower contract price.
We would favor the quote that meets the household's need and explains the required work at a price supported by comparable current bids. A higher price may reflect a different project, but the bidder should be able to explain the difference.
Your next step: Give two or more qualified providers the same equipment and scope questions, request written bids, and compare complete costs and responsibilities before choosing.