We install Navien and Rinnai units, and owner Anibal Nava has learned that the unit on the wall is the easy part. What actually decides whether a tankless install goes clean is the three things behind it: whether your gas line can carry the load, whether the venting run is right, and where the condensate goes. A cheap install that skips gas sizing is why so many of the tankless units we get called back to look at run cold at the third fixture.
Tankless water heater installation, done to spec
A tankless install is a real project, not a swap. A proper installation includes sizing the unit to your peak simultaneous demand, not just bedroom count (a 2-bath home and a 4-bath home need very different flow ratings); upsizing the gas line where the existing run can't carry the BTU load (this is the step budget installers skip); Category III stainless or concentric venting per the manufacturer's spec, with the correct run length and termination clearances; condensate drainage with a neutralizer on condensing units so acidic condensate doesn't eat your drain; and seismic and mounting per CA code, isolation valves for future flushing, and a City of Norwalk permit and inspection. Norwalk fact: LA County runs hard water, often 10 to 17 grains per gallon. A tankless heat exchanger scales up fast on water that hard, so we install isolation valves on every unit and walk you through an annual descaling flush. Skip that here and you cut the unit's life in half. We've seen the corner-cutting version too many times. If you want a plumber for tankless water heater installation who won't leave a starved gas line behind the drywall, call 213-254-8695 for a written quote.
What drives tankless water heater installation cost
A tankless install price is set by the work behind the wall, not just the unit on it. We won't quote a dollar figure sight-unseen because the same model can be a straightforward swap in one Norwalk home and a much bigger job three streets over. Four things actually move the number, in order of impact. First, the gas line upsize. Most tank heaters run on a 1/2" line. A tankless unit fires at a far higher BTU rate and usually needs 3/4" or larger back to the meter. If your run is long or undersized, upsizing that line is the single biggest cost driver, and it's non-negotiable for the unit to work. Second, the venting run and type. A short, straight run to an exterior wall is cheap. A long run, a roof termination, or a switch to concentric venting adds material and labor. Third, condensate and electrical. Condensing units need a condensate drain plus a neutralizer, and every tankless needs a nearby dedicated 120V outlet for the controls and igniter. If neither exists, that's added scope. Fourth, relocation. Moving the unit from a garage tank location to an exterior wall to shorten the vent changes gas, water, and vent routing all at once. The unit is the cheap part. Gas sizing, venting, and condensate are where an honest tankless quote lives, and where a lowball quote hides the corners it's cutting. We assess all four on-site, then put the full scope in writing so nothing shows up as a surprise after we start. Because tankless units so often need a larger gas line, this is where our natural gas piping work overlaps: if the main can't carry the new load, we quote the upsize alongside the install so you see one honest number. Ready when you are: 213-254-8695.
Gas line sizing and venting for a tankless unit
This is the part that separates a tankless install that lasts from one that disappoints, so we'll be specific. A standard 40 or 50-gallon tank sips gas at maybe 40,000 BTU. A whole-home tankless unit fires at 150,000 to 199,000 BTU on demand. Run that appetite through a gas line sized for a tank and the unit starves, throws error codes, and can't hold temperature when two showers run at once. We size the gas line against the BTU rating of the unit and the total developed length of the run back to the meter, then verify actual inlet pressure under firing load with a manometer before we sign off. On venting, a non-condensing unit needs Category III stainless; a condensing unit can vent in PVC or concentric pipe per the manufacturer, with strict clearances from windows, soffits, and property lines. We route the shortest compliant path and terminate it to code. What we verify before sign-off: gas line size against BTU load, inlet pressure under full fire on a calibrated manometer, vent length and termination clearances, and condensate flow to a neutralized drain. If any one of those is wrong, the unit underperforms, so we test all four. Most of the underperforming tankless units we get called to fix in Norwalk aren't bad units. They're good units on a gas line that was never upsized.
Tankless vs. tank: which is right for your home
Tankless isn't automatically the right answer, and we'll tell you straight when a tank is the smarter buy for your house. Here is the honest breakdown. Tankless earns its keep in larger homes with real simultaneous hot-water demand, and it delivers endless hot water and a smaller footprint, which matters in the tighter garages on older Norwalk tract lots. The tradeoff is a higher install cost, driven by the gas and venting work above, plus that annual descaling flush our hard water makes non-optional. For a 3-bath-and-up home with gas already at the meter, tankless is usually the call. For a 2-bath home with modest simultaneous use, a good 50-gallon tank is often the better value, and we'll say so. A standard tank still wins on upfront cost and simplicity, and for a smaller household it may be the better dollar-for-dollar choice. If a tank is the right move for you, we install those too. See our water heater and softener installation page for tank sizing and softener options, since a softener also protects a tankless heat exchanger from our hard water. Either way, we size both and let you compare real numbers instead of pushing the pricier unit.
When a tankless install is the wrong call
Here's the part most companies won't put in writing, because it can lose them the bigger sale. Don't buy a tankless unit just because it's the trendy upgrade. If your home is a smaller 1 to 2-bath household with low simultaneous use, if you have no natural gas service and would need a costly electrical upgrade to run an electric tankless, or if your gas main is badly undersized and sits a long developed length from the meter, the math often doesn't favor tankless. A quality tank heater will serve you better for less money. We'd rather tell you that on-site than sell you an install you'll regret when the payback never arrives. If tankless genuinely fits your home and your hot-water habits, we'll size it right and stand behind it.
Got questions?
Frequently asked questions
Do you pull permits for tankless installs in Norwalk?
Yes, always. A tankless water heater installation in Norwalk requires a City of Norwalk permit and an inspection, and we pull it, schedule the inspection, and stand for it. That covers gas line work, venting, and seismic strapping per CA code. No undocumented work and no liability questions when you sell the home later.
How long does a tankless water heater installation take?
A straightforward conversion where the gas line and venting need only minor work is often a one-day job. If we need to upsize the gas line back to the meter, add a longer or re-routed vent, or run new condensate and electrical, it can stretch to two days. We give you the realistic timeline in writing with the quote, not an optimistic guess.
Will my existing gas line and electrical support a tankless unit?
Often the gas line needs upsizing. Most tank heaters run on a 1/2" line, and a whole-home tankless firing at 150,000 to 199,000 BTU usually needs 3/4" or larger, sized to the run length back to the meter. Every tankless also needs a nearby 120V outlet for its controls. We check both on-site, verify inlet pressure under full fire with a manometer, and quote any upsize as part of the written scope so there are no surprises.
Which tankless brands do you install?
We install Navien and Rinnai, the two brands we've had the best long-term results with on our Norwalk installs. We size the specific model to your peak simultaneous demand rather than defaulting to whatever's cheapest, and we set it up with isolation valves so the annual descaling flush our hard water requires is quick and cheap to do.
Are you licensed, bonded and insured?
Yes. Nava's Elite Plumbing carries a current California master plumber registration, $1M general liability coverage, and workers' comp on every technician. A certificate of insurance naming you or your property manager is available on request before we start.
Do you give upfront pricing?
Every job is quoted in writing before any work begins. We price by scope, not by the hour, so the number you approve is the number you pay — barring scope changes you approve in writing.
Do you require money down?
No deposit on standard service calls. On larger projects (repipes, sewer replacements, gas line installs) we phase work into progress payments tied to city inspection milestones — you never pay ahead of completed work.