Brands

Navien

Best known for condensing gas tankless units and for recirculation built into the unit rather than bolted on afterwards. Since the NWP500 line they also make heat pump water heaters, which matters if you assumed choosing Navien meant choosing tankless. A strong choice in the right house, and an expensive mistake in the wrong one.

Worth shortlisting if

You are converting to gas tankless and want recirculation
Your household runs several fixtures at once
There are experienced Navien installers near you
You are replacing an existing Navien unit

Look elsewhere if

Nobody local services the brand well
You will not keep up with annual descaling
A storage tank or heat pump is the better technology anyway
Your gas service cannot support a tankless unit

What we have verified, and what we have not

Warranty terms, model lines and installer programmes change without notice, and they vary by model, registration and installation type. Rather than publish a number that quietly goes stale, each row shows its own state.

The Navien brand record

Technologies made: Condensing gas tankless (NPE-A2 line) and heat pump water heaters (NWP500 line, 50, 65 and 80 gallon). Also produces combi boilers.
Source: Navien residential water heater rangeChecked 7 Aug 2026
Tankless output: NPE-240A2 is rated 11.2 GPM at a 35°F temperature rise and 5.6 GPM at around a 67°F rise. Size against the rise your winter groundwater actually requires, not the headline figure.
Source: Navien NPE-240A2 product specificationChecked 7 Aug 2026
Heat pump sizing: NWP500-65 is rated around 63 gallons with an 80 gallon first hour rating. Unducted installation needs roughly 450 cubic feet of surrounding air, and it runs on a 208 to 240V, 30A circuit.
Source: Navien NWP500 series specificationChecked 7 Aug 2026
Warranty, NPE-A2 residential: With standard or controlled recirculation: 15 years heat exchanger, 5 years parts, 1 year labour.
With uncontrolled recirculation the same line drops to 5 years heat exchanger and 3 years parts. If you are adding a recirculation loop, this single detail is worth thousands.
Line level, not model level, and conditions attach. Navien also states that internet or e-commerce purchase can void cover. Ask for the warranty document for the exact model you are quoted.
Source: Navien NPE-A2 warranty termsChecked 7 Aug 2026
Installer programme: Navien Service Specialist (NSS). We found no blanket requirement that an installer hold it, but it is a useful serviceability signal.
Source: Navien NSS programme pageChecked 7 Aug 2026
Local programme coverage: VerifyNot established for the Modesto area.
Navien’s installer list cannot be read without first agreeing that Navien may share your details with installers, so we have not confirmed whether any local company holds NSS. Read that as unknown rather than as evidence either way. Rinnai and Noritz both publish theirs openly, and both show local coverage.
We will not describe any installer as authorised, certified or trained unless that exact status appears in the manufacturer’s own current directory.
Parts availability, Central Valley: Mixed. PACE Supply publicly lists Navien and states it carries a large Northern California tankless and repair parts inventory. Exact Modesto and Ripon stock still needs checking.
Source: PACE Supply water heater solutions listingChecked 7 Aug 2026
Consumer financing: None at manufacturer level in the United States. Navien runs a financing programme called NaviLend, but it is a Canadian programme launched with a Canadian lender, and Navien's US rebates and credits page carries no financing at all. Articles that list Navien financing as a US homeowner benefit are reading a Canadian announcement. Any financing on your quote will be your installer's own.
Source: Navien US rebates and credits page, and the NaviLend Canada launch announcementChecked 20 Aug 2026

Navien or Rinnai

The comparison most people arrive wanting. Both publish a headline near 11 GPM and both land near 6 GPM at a Central Valley winter, so the flow question is a dead heat and the decision sits elsewhere. We converted the numbers and laid out the rest.

Ask your installer these before committing to the brand

How many of these have you installed in the last year?
Who services it when it throws a code, you or someone else?
Are parts held locally, or ordered in?
What does the warranty require me to do to keep it valid?
Would you put this brand in your own house, and why?

Check whether tankless is right first Compare all brands