What Tankless Water Heater Do I Need?
Find the tankless units that actually fit your home
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Shopping for a tankless water heater gets overwhelming fast — dozens of models, and spec sheets that read like a foreign language. This makes it simple: you tell us what you have, and we’ll tell you what will work. Answer a few quick questions about your home and your gas line, and the tool narrows all the models down to the ones that will actually work for your home — and shows you why the rest don’t. For every match you’ll see the things that matter in plain terms: how much hot water it puts out, what it takes to install, how efficient it is, and how long it’s warrantied. It’s the same sizing our techs use, so you can see your real options before anyone comes out.How to use it: in the Calculator, set how many fixtures run at the same time, choose your temperature rise (we set it to the 70°F year-round option so your hot water holds up in winter, not just summer), and enter your gas-line length. The model list updates as you go — any model that can’t meet your conditions drops off, with the reason why.
When you’re done, we’ll confirm the final pick on site: Call (714) 964-3519
67 current + legacy residential models · set your conditions in the Calculator, units drop off with the reason · specs from manufacturer sheets
Hard specs are from manufacturer spec sheets; "—" or a verify flag means the maker doesn't publish that number (several publish a flow curve instead of a value at a set rise; discontinued units have thinner data) — the tool won't eliminate on missing data and won't guess. Gas pipe size is a code-table estimate (IFGC, 0.5" w.c. drop) from each unit's BTU and your developed length — confirm on the job. All units come in NG and LP, and all are Ultra-Low-NOx (SCAQMD-compliant). In Orange County an outdoor unit is fully viable and needs no venting at all.
Manufacturer
None checked = show all.
Install
Type
Condensing ≈ 90–98% efficient (UEF) — vents in inexpensive PVC and burns less gas. Non-condensing ≈ 79–82% — lower price up front, but needs pricier Cat III stainless venting and costs more to run.
What could run at the same time?
Tap everything that might run together on a busy morning. The number in parentheses is the hot water that fixture pulls, in gallons per minute (GPM).
Restrictors removed? If your showerheads have had the flow restrictors taken out, count each shower as about three. A restrictor-free head can flow near 5.5 GPM instead of 1.8 — that is 4.13 GPM of hot water per shower, not 1.35. Why this matters →
Temperature rise (how many degrees the heater has to warm the incoming water)
This is the setting that matters most. Your heater has to bring the incoming water up to about 120°F. In summer the incoming water is warmer, so that's only a ~45–55°F jump — but in winter the incoming water is colder, the jump gets bigger (about 70°F), and a unit sized only for summer will put out noticeably less hot water in the months you need it most. We default to the 70°F rise so the units you see hold their output every month of the year. The 45–55°F option is the bare minimum, not the best — switch to it only if you want to see the summer best-case.
Gas line to meter — developed length
Measure the routed pipe, not the straight line: up the wall, across the attic/ceiling, back down to the unit. Add it up (≈+5 ft per elbow). Not sure? Typical single-story run ≈20–30 ft, two-story ≈40–60 ft (we default to 25). Shows the gas pipe size each unit needs.
Existing gas line (optional)
If a unit needs a bigger line than you have, it stays on the list with an “upsize” flag — upsizing the gas line is a normal part of the install, not a dealbreaker.
Features
Ruled out (and why)
‡ What the venting terms mean
PVC · Cat IV — a condensing (high-efficiency) unit runs cool enough to vent through standard PVC or CPVC plastic pipe. This is the least expensive venting to install and the reason most homeowners end up on a condensing unit.
Concentric vent — a single manufacturer-specific fitting that carries exhaust and combustion-air intake in one pipe-within-a-pipe (e.g. Rinnai's 3"/5"). It only needs one hole through the wall or roof instead of two, but you must buy that maker's vent kit — you can't mix brands. Common on some non-condensing indoor models.
Stainless · Cat III — a non-condensing unit runs hot, so its exhaust must go through special sealed stainless-steel venting (AL29-4C). This vent pipe is expensive — often several hundred dollars in materials alone — and is the main hidden cost of a non-condensing tankless.
Outdoor · none — an outdoor-rated unit mounts on an exterior wall and vents straight to open air, so there's no venting to buy at all. In Orange County's mild climate this is a fully viable, low-cost option.
Tankless water heater specs by brand — Navien, Rinnai, Noritz, Takagi, Rheem and Bosch models we install in Orange County
See the full spec sheet — all 67 tankless models we install & service in Orange County
Every residential tankless water heater Professional Plumbing Inc installs and services across Orange County — Navien, Rinnai, Noritz, Takagi, Rheem, Bosch — with the manufacturer specs the tool above uses: model, type, indoor/outdoor rating, flow rate (GPM) at temperature rise, max BTU, gas connection, venting, efficiency (UEF), and heat-exchanger warranty. Call (714) 964-3519 for help choosing.
| Model | Brand | Type | Install | Max GPM | GPM @45°F | GPM @70°F | Max BTU | Gas line | Venting | Heat exchanger | UEF | HX warranty | Status | Notes |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| NPE-180S2 | Navien | Condensing | Indoor / Outdoor | 8.4 | 6.5 | 4.2 | 150k | 3/4" | PVC (Cat IV) | Dual stainless | 0.96 | 15 yr | Current | |
| NPE-210S2 | Navien | Condensing | Indoor / Outdoor | 10.1 | 7.8 | 5 | 180k | 3/4" | PVC (Cat IV) | Dual stainless | 0.96 | 15 yr | Current | |
| NPE-240S2 | Navien | Condensing | Indoor / Outdoor | 11.2 | 8.7 | 5.6 | 200k | 3/4" | PVC (Cat IV) | Dual stainless | 0.96 | 15 yr | Current | |
| NPE-210A2 | Navien | Condensing | Indoor / Outdoor | 10.1 | 7.8 | 5 | 180k | 3/4" | PVC (Cat IV) | Dual stainless | 0.95 | 15 yr | Current | ComfortFlow recirc + buffer |
| NPE-240A2 | Navien | Condensing | Indoor / Outdoor | 11.2 | 8.7 | 5.6 | 200k | 3/4" | PVC (Cat IV) | Dual stainless | 0.95 | 15 yr | Current | ComfortFlow recirc + buffer |
| NPN-180E | Navien | Non-condensing | Outdoor | 8.5 | 6.6 | 4.3 | 180k | 3/4" | Outdoor — none | Stainless | 0.81 | 15 yr | Current | Outdoor, non-condensing |
| NHW-199AI | Navien | Non-condensing | Indoor | 11.1 | 7.4 | 4.7 | 200k | 3/4" | Stainless (Cat III) | Stainless | 0.81 | 15 yr | Current | Metal concentric NaviVent (Cat III-class) |
| NHW-199AE | Navien | Non-condensing | Outdoor | 11.1 | 7.4 | 4.7 | 200k | 3/4" | Outdoor — none | Stainless | 0.81 | 15 yr | Current | |
| NHW-199SU | Navien | Non-condensing | Indoor / Outdoor | 11.1 | 7.4 | 4.7 | 200k | 3/4" | Stainless (Cat III) | Stainless | 0.81 | 15 yr | Current | No built-in pump |
| RX160iN | Rinnai | Condensing | Indoor / Outdoor | 9 | 6.9 | 4.5 | 160k | 3/4" | PVC (Cat IV) | Stainless | 0.97 | 15 yr | Current | 444 stainless HX |
| RX180iN | Rinnai | Condensing | Indoor / Outdoor | 10 | 7.8 | 5 | 180k | 3/4" | PVC (Cat IV) | Stainless | 0.98 | 15 yr | Current | |
| RX199iN | Rinnai | Condensing | Indoor / Outdoor | 11 | 8.6 | 5.5 | 199k | 3/4" | PVC (Cat IV) | Stainless | 0.98 | 15 yr | Current | |
| RXP199iN | Rinnai | Condensing | Indoor / Outdoor | 11 | 8.6 | 5.5 | 199k | 3/4" | PVC (Cat IV) | Stainless | 0.98 | 15 yr | Current | Built-in Smart-Circ pump |
| RSC160iN | Rinnai | Condensing | Indoor | 8 | — | — | 160k | 3/4" | PVC (Cat IV) | Stainless | 0.93 | 15 yr | Current | Flow-at-rise not published (curve) |
| RSC199iN | Rinnai | Condensing | Indoor | 9.8 | — | — | 199k | 3/4" | PVC (Cat IV) | Stainless | 0.93 | 15 yr | Current | Flow-at-rise not published (curve) |
| RE140iN | Rinnai | Non-condensing | Indoor | 5.3 | — | — | 140k | 3/4" | Concentric | Copper | 0.81 | 15 yr | Current | Rinnai 3"/5" concentric vent |
| RE160iN | Rinnai | Non-condensing | Indoor | 6.6 | — | — | 160k | 3/4" | Concentric | Copper | 0.81 | 15 yr | Current | Rinnai 3"/5" concentric vent |
| RE180iN | Rinnai | Non-condensing | Indoor | 8.5 | — | — | 180k | 3/4" | Concentric | Copper | 0.82 | 15 yr | Current | Rinnai 3"/5" concentric vent |
| REP160iN | Rinnai | Non-condensing | Indoor | 6.6 | — | — | 160k | 3/4" | Concentric | Copper | 0.81 | 15 yr | Current | Built-in pump; 3"/5" concentric vent |
| REP199iN | Rinnai | Non-condensing | Indoor | 7.9 | — | — | 199k | 3/4" | Concentric | Copper | 0.82 | 15 yr | Current | Built-in pump; 3"/5" concentric vent |
| RL75iN | Rinnai | Non-condensing | Indoor | 7.5 | — | — | 180k | 3/4" | Stainless (Cat III) | Not published | 0.81 | 12 yr | Current | Cat III stainless venting required |
| RL94iN | Rinnai | Non-condensing | Indoor | 9.8 | — | — | 199k | 3/4" | Stainless (Cat III) | Not published | 0.81 | 12 yr | Current | Cat III stainless venting; (replaces the "RL100" — not a real model) |
| RUCS65iN | Rinnai | Condensing | Indoor | 6.5 | — | — | 130k | 3/4" | PVC (Cat IV) | Stainless | 0.85 | 15 yr | Current | Ultra series (condensing, compact) |
| EZ71DV | Noritz | Condensing | Indoor / Outdoor | 9 | 6.9 | 4.4 | 160k | 3/4" | PVC (Cat IV) | Stainless | 0.98 | 25 yr | Current | |
| EZ98DV | Noritz | Condensing | Indoor / Outdoor | 9.8 | 7.7 | 4.9 | 180k | 3/4" | PVC (Cat IV) | Stainless | 0.98 | 25 yr | Current | |
| EZ111DV | Noritz | Condensing | Indoor / Outdoor | 11.1 | 8.7 | 5.6 | 200k | 3/4" | PVC (Cat IV) | Stainless | 0.98 | 25 yr | Current | |
| EZTR40 | Noritz | Condensing | Indoor | 6.6 | 4.9 | — | 120k | 1/2" | PVC (Cat IV) | Copper + stainless | 0.87 | 12 yr | Current | a.k.a. NRC663-FSV |
| EZTR50 | Noritz | Condensing | Indoor / Outdoor | 9.8 | — | — | 180k | 3/4" | PVC (Cat IV) | Stainless | 0.98 | 25 yr | Current | |
| EZTR75 | Noritz | Condensing | Indoor / Outdoor | 11.1 | — | — | 200k | 3/4" | PVC (Cat IV) | Stainless | 0.98 | 25 yr | Current | |
| NRC661 | Noritz | Condensing | Indoor / Outdoor | 6.6 | 5.3 | 3.3 | 120k | 1/2" | PVC (Cat IV) | Copper | 0.89 | 12 yr | Current | Condensing (verified) |
| NRC711 | Noritz | Condensing | Indoor / Outdoor | 7.1 | 5.8 | 4.2 | 157k | 1/2" | PVC (Cat IV) | Copper | 0.89 | 12 yr | Current | Condensing (verified) |
| NRC98DV | Noritz | Condensing | Indoor | 9.8 | 7.5 | 4.8 | 180k | 3/4" | PVC (Cat IV) | Copper | 0.9 | 12 yr | Current | |
| NRC98OD | Noritz | Condensing | Outdoor | 9.8 | 7.5 | 4.8 | 180k | 3/4" | Outdoor — none | Copper | 0.92 | 12 yr | Current | |
| NRC111DV | Noritz | Condensing | Indoor | 11.1 | 8.4 | 5.3 | 200k | 3/4" | PVC (Cat IV) | Copper | 0.91 | 12 yr | Current | |
| NRC111OD | Noritz | Condensing | Outdoor | 11.1 | 8.4 | 5.3 | 200k | 3/4" | Outdoor — none | Copper | 0.93 | 12 yr | Current | |
| NRC1111 | Noritz | Condensing | Indoor / Outdoor | 11.1 | 8.4 | 5.3 | 200k | 3/4" | PVC (Cat IV) | Copper | — | 12 yr | Legacy | Legacy; rated EF not UEF |
| NRCP98-DV | Noritz | Condensing | Indoor | 10.1 | 7.8 | 4.9 | 180k | 3/4" | PVC (Cat IV) | Stainless | 0.94 | 12 yr | Discontinued | Built-in pump |
| NRCP111-DV | Noritz | Condensing | Indoor | 11.1 | 8.6 | 5.4 | 199k | 3/4" | PVC (Cat IV) | Stainless | 0.94 | 12 yr | Discontinued | Built-in pump |
| T-H3-DV | Takagi | Condensing | Indoor | 10 | — | — | 199k | 3/4" | PVC (Cat IV) | Copper + stainless | 0.93 | 15 yr | Current | = A.O. Smith ATI-540H |
| T-H3-OS | Takagi | Condensing | Outdoor | 10 | — | — | 199k | 3/4" | Outdoor — none | Copper + stainless | 0.95 | 15 yr | Current | |
| T-H3S-DV | Takagi | Condensing | Indoor | 8 | — | — | 180k | 3/4" | PVC (Cat IV) | Copper + stainless | 0.95 | 15 yr | Current | = ATI-340H |
| T-H3J-DV | Takagi | Condensing | Indoor | 6.6 | — | — | 160k | 3/4" | PVC (Cat IV) | Copper + stainless | 0.94 | 15 yr | Current | = ATI-240H |
| T-H3M | Takagi | Condensing | Indoor | 6.6 | — | — | 120k | 1/2" | PVC (Cat IV) | Copper + stainless | 0.9 | 15 yr | Current | = ATI-140H |
| TK-540X3-NIH | Takagi | Condensing | Indoor | 10 | — | — | 199k | 3/4" | PVC (Cat IV) | Copper + stainless | 0.93 | 15 yr | Current | X3 = scale prevention (NOT a pump) |
| TK-540X3-NEH | Takagi | Condensing | Outdoor | 10 | — | — | 199k | 3/4" | Outdoor — none | Copper + stainless | 0.95 | 15 yr | Current | X3 = scale prevention (NOT a pump) |
| T-D2-IN | Takagi | Non-condensing | Indoor | 10 | — | — | 199k | 3/4" | Stainless (Cat III) | Copper | 0.8 | 15 yr | Current | Cat III stainless venting ($$) |
| T-D2-OS | Takagi | Non-condensing | Outdoor | 10 | — | — | 199k | 3/4" | Outdoor — none | Copper | 0.8 | 15 yr | Current | |
| T-K4-IN | Takagi | Non-condensing | Indoor | 8 | — | — | 190k | 3/4" | Stainless (Cat III) | Copper | 0.8 | 15 yr | Current | Cat III stainless venting ($$) |
| T-K4-OS | Takagi | Non-condensing | Outdoor | 8 | — | — | 190k | 3/4" | Outdoor — none | Copper | 0.8 | 15 yr | Current | |
| T-KJr2-IN | Takagi | Non-condensing | Indoor | 6.6 | — | — | 140k | 3/4" | Stainless (Cat III) | Copper | 0.79 | 15 yr | Current | Cat III stainless venting ($$) |
| T-KJr2-OS | Takagi | Non-condensing | Outdoor | 6.6 | — | — | 140k | 3/4" | Outdoor — none | Copper | 0.79 | 15 yr | Current | |
| RTGH-68DVLN | Rheem | Condensing | Indoor / Outdoor | 6.6 | 5.1 | — | 120k | 3/4" | PVC (Cat IV) | Copper + stainless | 0.9 | 15 yr | Current | |
| RTGH-84DVLN | Rheem | Condensing | Indoor / Outdoor | 8.4 | 6.7 | — | 157k | 3/4" | PVC (Cat IV) | Copper + stainless | 0.93 | 15 yr | Current | |
| RTGH-95DVLN | Rheem | Condensing | Indoor / Outdoor | 9.5 | 8.5 | — | 200k | 3/4" | PVC (Cat IV) | Copper + stainless | 0.93 | 15 yr | Current | |
| RTGH-95XLN | Rheem | Condensing | Outdoor | 9.5 | 8.5 | — | 200k | 3/4" | Outdoor — none | Copper + stainless | 0.93 | 12 yr | Legacy | |
| RTGH-RH10DVLN | Rheem | Condensing | Indoor | 9.9 | 7.7 | 5 | 180k | 3/4" | PVC (Cat IV) | Copper + stainless | 0.94 | 12 yr | Current | Built-in pump + buffer |
| RTGH-RH11DVLN | Rheem | Condensing | Indoor | 11 | 8.5 | 5.5 | 199k | 3/4" | PVC (Cat IV) | Copper + stainless | 0.94 | 12 yr | Current | Built-in pump + buffer |
| RECTGH-SR10iN (IKONIC) | Rheem | Condensing | Indoor / Outdoor | 10.1 | 7.9 | — | 180k | 3/4" | PVC (Cat IV) | Dual stainless | 0.96 | 15 yr | Current | Dual stainless; built-in pump; EcoNet Wi-Fi |
| RTG-84XLN | Rheem | Non-condensing | Outdoor | 8.4 | 6.7 | — | 180k | 3/4" | Outdoor — none | Copper | 0.81 | 15 yr | Current | |
| RTG-95DVLN | Rheem | Non-condensing | Indoor | 9.5 | 7.4 | — | 200k | 3/4" | Stainless (Cat III) | Copper | 0.82 | 15 yr | Current | Cat III stainless venting ($$) |
| RTG-95XLN | Rheem | Non-condensing | Outdoor | 9.5 | 7.4 | — | 200k | 3/4" | Outdoor — none | Copper | 0.82 | 15 yr | Current | |
| Greentherm T9900 SE 160 | Bosch | Condensing | Indoor | 9 | 7 | — | 160k | 3/4" | PVC (Cat IV) | Copper + stainless | 0.96 | 15 yr | Discontinued | Built-in pump |
| Greentherm T9900 SE 199 | Bosch | Condensing | Indoor | 11.2 | 8.7 | — | 199k | 3/4" | PVC (Cat IV) | Copper + stainless | 0.95 | 15 yr | Discontinued | Built-in pump |
| Greentherm T9800 SE 199 | Bosch | Condensing | Indoor | 11.2 | 8.7 | — | 199k | 3/4" | PVC (Cat IV) | Copper + stainless | — | 15 yr | Discontinued | |
| Greentherm T9800 SEO 199 | Bosch | Condensing | Outdoor | 11.2 | 8.7 | — | 199k | 3/4" | Outdoor — none | Copper + stainless | — | 15 yr | Discontinued | |
| Therm 940ES | Bosch | Non-condensing | Indoor | 9.4 | 7.3 | — | 199k | nv | Stainless (Cat III) | Copper | — | 15 yr | Legacy | Cat III stainless venting ($$); legacy |
| Therm 940ESO | Bosch | Non-condensing | Outdoor | 9.4 | 7.2 | — | 199k | nv | Outdoor — none | Copper | — | 15 yr | Legacy | Legacy |
© 2026 Professional Plumbing Inc. · Specs compiled from manufacturer sources for Prof Plumbing — not for reproduction. Your final pick depends on the gas line and venting on site — a free 20-minute visit.
