Compare scopes, not totals
Two quotes for a tankless conversion can differ because one includes a new gas line and a side-wall vent while the other assumes the existing pipe and flue will do. The worksheet below forces those assumptions into the open.
Fill in one column per quote straight from the written document. If something is not written down, mark it as not stated and ask about it. This site does not suggest prices; the point is to compare what each plumber is actually offering.
Comparison grid
| Item | Quote A | Quote B | Quote C |
|---|---|---|---|
| Plumber's CSLB license number (verified at cslb.ca.gov) | |||
| Unit make and model | |||
| Flow rating at your temperature rise | |||
| Condensing or non-condensing | |||
| Gas piping work and route | |||
| Vent material, route and termination | |||
| Service valves with flush ports | |||
| Pressure relief valve and discharge | |||
| Condensate drain or neutralizer | |||
| Electrical outlet or circuit | |||
| Permit and inspection | |||
| Old tank removal and old flue handling | |||
| Exclusions and possible extras | |||
| Total |
Red flags to circle
- No license number, or a number that does not match the business name
- No mention of gas line size on a conversion
- Vent route not described
- Permit not mentioned
- Large amount due before any work or materials
- Verbal promises that are not in the written quote
After you fill it in
- Mark the gaps.Highlight every cell that says not stated.
- Ask the same follow-ups.Send each plumber the same questions so answers line up.
- Update in writing.Ask for revised quotes rather than accepting changes by phone.
- Choose on scope and trust.The best quote fits your house and is clear about what it includes.
Common questions
What if one quote uses a different brand?
Compare flow rating at your temperature rise and the installation scope, not brand names.
Is the cheapest quote a bad sign?
Not necessarily. Check whether it leaves out gas, venting or permit work that the others include.
How many quotes should I compare?
Two or three itemized quotes for the same scope are usually enough.
General information for Fullerton, not a quote or professional advice. In an emergency, call 911.