Navien vs Noritz tankless water heaters is a closer match than the brochures suggest: the Navien NPE-2 series and the Noritz EZ series are both condensing units with dual stainless steel heat exchangers rated at up to 0.95 UEF. Choose the Navien NPE-240A2 if you want recirculation built in and the full 199,900 BTU/h. Choose a Noritz EZ if the heater is replacing a tank and its top-mounted water connections save re-piping. On hard water in Halton and Hamilton, the deciding factor is which one your installer can descale and get parts for quickly.
Navien NPE-2 and Noritz EZ at a Glance
- Navien NPE-A2 (NPE-180A2, 210A2 and 240A2): 150,000, 180,000 and 199,900 BTU/h maximum input; dual stainless steel heat exchangers; up to 15:1 turndown; water connections on the bottom; a built-in recirculation pump and buffer tank, which Navien calls ComfortFlow.
- Navien NPE-S2: the same series without the pump and buffer tank. The NPE-A2 vs NPE-S2 comparison covers when the pump is worth paying for.
- Noritz EZ98 and EZ111: 18,000 to 180,000 BTU/h input; dual stainless steel heat exchangers; water connections on top, where a tank's are; no recirculation pump listed on the EZ models, with recirculation sold as a separate Noritz line (NRCR).
- Warranty in a single-family home: Navien lists 15 years on the heat exchanger, 5 on parts and 1 on labour; Noritz lists 25 years on the heat exchanger, 5 on parts and 1 on labour for the EZ series, with registration required.
Those figures are from each manufacturer's product and warranty pages as of October 2026. Model details change, so the rating plate and the warranty card that come with the unit are the final word.
Hot Water Output: 199,900 Against 180,000 BTU/h
The largest Navien delivers about 10% more hot water than either Noritz EZ model, because output in an Ontario winter is set by burner input, not by the gallons-per-minute figure on the box. Noritz rates the EZ98 at 9.8 and the EZ111 at 11.1 gallons a minute, but those are maximum flows at a mild temperature rise. In February, with water coming in from the main only a few degrees above freezing, a 180,000 BTU/h unit raises a bit under 5 gallons a minute by 40°C and a 199,900 BTU/h unit a bit over 5.
For two showers at once that difference rarely matters. For a large soaker tub, a rain-head shower or a house with four bathrooms, it can decide between one unit and two. Have the fixtures counted and the flow added up before a model goes on the quote.
Recirculation: Built In on the Navien A2, Separate on Noritz
If you want hot water at a far bathroom without a long wait, the NPE-A2 has the pump and a small buffer tank inside the cabinet. It can circulate through a dedicated return line or, with a crossover valve, through the cold line in a house that has no return. The buffer tank also softens the cold-water sandwich, the burst of cool water between back-to-back draws. With a Noritz EZ you add an external pump and control, or buy the recirculating NRCR line instead.
Recirculation changes the warranty on both brands, so read that part of the card before the pump is wired. Navien keeps its 15-year heat exchanger term for standard or controlled recirculation and cuts it to 5 years, with 3 on parts, where an external pump circulates continuously. Noritz drops its 25-year heat exchanger term to 15 years where the unit handles circulated water, and asks for a controlled system with at least an aquastat. With recirculation running, the two warranties end up level at 15 years.
Gas Line and Venting: What the Brochures Claim and What the Code Requires
Both makers advertise that their units can use the gas line and vent path an old tank left behind. Navien states half-inch gas pipe up to 24 feet and 2-inch PVC venting up to 75 feet for the NPE-A2. Noritz describes the EZ as compatible with a half-inch gas line and sells it bundled with a 25-foot, 2-inch flexible vent kit designed to be pulled through the old tank's vent.
Those claims describe what the appliance can tolerate, not what your house can supply. A tank burns about 40,000 BTU/h; these units burn 180,000 to 199,900. Under CSA B149.1 the pipe is sized for the total connected load, the length back to the meter and the supply pressure, and most Ontario houses are on low-pressure gas. A half-inch branch that shares its supply with a furnace, a range and a dryer will often fail the sizing table no matter what the brochure says, and then the run is upsized, which typically adds $400–$1,200.
Venting has the same catch. In Ontario, plastic vent pipe on a gas appliance has to be certified to ULC S636, so ordinary plumbing PVC or ABS is not allowed even where a manual says PVC. Whether the Noritz flex kit can go up a particular B-vent or chimney depends on its listing and on what else vents there, and we confirm that before quoting it. Both units also produce acidic condensate that needs a drain, and both need a 120 V receptacle.
Free quotes, written pricing.
Hard Water, Descaling and Error Codes in Halton and Hamilton
Scale is what kills tankless heat exchangers here, and it is the reason service access outranks brand. Both units need isolation valves with flush ports fitted at install so a technician can circulate descaling solution through the heat exchanger; an annual descale flush runs $150–$300. Skip the valves to save money on install day and every future flush costs more.
Noritz puts a number on it: its warranty excludes damage where water hardness is above 12 grains per gallon (200 mg/L), and damage from untreated or poorly treated well water. Lake-supplied municipal water in this area is hard enough to scale a heat exchanger but generally tests under that line; a private well, or a municipal supply fed by groundwater instead of the lake, can test well over it. Get the hardness tested before you buy either brand, and budget for a softener if it is high. Our guide to hard water and tankless heaters in Hamilton and Halton goes deeper.
When something does go wrong, both display a code. On a Navien, E003 is an ignition failure, E012 a flame loss and E016 heat exchanger overheating, which on hard water usually means scale. On a Noritz, 11 is an ignition failure and 90 a combustion fault. The full lists are in our Navien error code guide and Noritz error code guide, and the label inside the panel always overrides a general list.
Parts and Service in the GTA
Navien is one of the two brands most often installed in GTA tank-to-tankless conversions, so more local technicians know its codes and carry its common parts. Noritz has a smaller installed base here. That is not a quality judgment, but it changes what a breakdown looks like: ask any installer quoting a Noritz where parts come from and how long an igniter, a flow sensor or a fan takes to arrive. Ask the same about a Navien; the answer should be short.
ZK Mechanical's regular tankless brands are Navien, Rinnai and Bosch, and we also work on Noritz units already installed in the area. For either one, a no-hot-water call starts with the standard $90–$150 diagnostic, credited toward the repair.
What Either One Costs Installed
- Tank-to-tankless conversion with a mid-tier 199,000 BTU gas unit: $4,200–$5,000 installed is typical
- Full range for tankless installs, including gas-line and venting work: $3,500–$6,500
- Gas line upsizing where the existing run fails the sizing table: +$400–$1,200
- Annual descale flush: $150–$300
Brand moves the total less than the gas line, the vent route and whether a recirculation loop is being added. A quote far below the range has usually left out one of those three.
Verdict: Navien for Most GTA Homes, Noritz for a Tight Tank Replacement
For most houses we would install the Navien NPE-240A2. It has the higher input, the pump and buffer tank are inside the cabinet, its 15-year heat exchanger warranty survives controlled recirculation, and it is the easier of the two to get serviced in the GTA.
- Choose the Navien NPE-240A2 for a family home with three or more bathrooms, a far-away ensuite, or any plan to add recirculation.
- Choose the Navien NPE-S2 if you want the same series without recirculation at a lower price.
- Choose a Noritz EZ98 or EZ111 when the heater is going exactly where a tank stood, the piping drops from above, and reusing the vent path saves opening walls. Its 25-year heat exchanger term is the longest here, as long as there is no recirculation and the water is within the hardness limit.
- Choose neither until the gas line has been sized and the water hardness tested.
We size the gas line, test the water and price the venting before recommending a model. See tankless water heater installation, or book a quote and tell us where the old tank sits.
Frequently asked questions
Is Noritz as reliable as Navien?
On paper they are peers: both are condensing units with stainless steel heat exchangers and long warranties. In the field, reliability depends less on the badge than on the install. A correctly sized gas line, a vent within its length limit, a trapped condensate drain and a yearly descale decide whether either brand runs for 15 years or throws ignition and overheat codes in year three.
Can a Navien or Noritz reuse my old water heater's vent?
Not as it is. A tank's metal B-vent cannot carry the cool, wet exhaust of a condensing unit. A Navien gets new certified plastic pipe through a sidewall or the roof. The Noritz EZ is designed so a flexible liner can be pulled through the old vent, using it only as a chase, if the kit is approved for that vent and nothing else exhausts into it.
How often does a tankless need descaling on Burlington or Hamilton water?
Once a year on municipal water is the rule we work to, and more often on an untreated well. The signs that it is overdue are water temperature that hunts up and down, a rumbling or kettling noise from the cabinet, reduced flow at the hot taps, and on a Navien an E016 overheat code. A softener stretches the interval but does not remove the need.
Does either brand qualify for an Ontario rebate?
No. No current Ontario program pays a rebate for a gas tankless water heater of any brand, so neither a Navien nor a Noritz comes with one. The Home Renovation Savings Program directs its water-heating incentives at heat pump water heaters. If a quote promises a tankless rebate, ask which program and get the name in writing before you sign.