Question 1

Which tankless water heater brand is most reliable?

Accepted Answer

Rinnai and Navien consistently receive the highest reliability ratings in the premium gas category. Rinnai has been manufacturing tankless water heaters since 1964 and offers a 12-year heat exchanger warranty. Navien offers a 15-year heat exchanger warranty and is known for condensing efficiency. For budget gas options, Noritz has a strong reliability record. For electric, Stiebel Eltron (German-made) is the reliability leader but at premium prices; Rheem is the best value for electric.

Question 2

Is Rinnai or Navien better?

Accepted Answer

For long-term reliability: Rinnai. Larger certified installer network, longer track record, easier to find parts and service techs. For maximum efficiency: Navien. Higher UEF ratings and 15-year HX warranty. Navien's condensate system adds installation complexity. Key trade-off: Navien units typically cost $300–$500 more and $1,000–$2,000 more to install due to condensate drain requirements. If your home is already set up for condensate drainage, Navien is excellent. If not, Rinnai is usually the better choice.

Question 3

Why do Rinnai and Navien require certified installers?

Accepted Answer

Both Rinnai and Navien strongly prefer certified installers (Rinnai's ProPartner programme; Navien's NSI programme) for several reasons: (1) Proper venting and gas pressure configuration is critical to efficiency and safety. (2) Warranty claims are easier to process through certified installers. (3) Certified installers often get wholesale pricing on units, which can offset their higher labor rate. While non-certified plumbers can legally install these units in most states, using certified installers is worth the modest premium for premium brands.

Question 4

Where is the best place to buy a tankless water heater?

Accepted Answer

For Rheem and EcoSmart: Home Depot and Lowe's offer competitive pricing and hassle-free returns. For Rinnai: Plumbing supply houses (Ferguson, Weinstein) and Amazon often have better prices than retail. For Navien: Navien's dealer network and plumbing supply houses — Navien units are rarely found at big-box stores. For budget units: Amazon offers competitive pricing with Prime delivery. Important: buying the unit separately and supplying it to your installer can save $150–$400 vs the installer markup.

Brand	Unit Cost	Installed Total	HX Warranty	Condensing?	Fuel	Install Complexity
Rinnai	$500–$1,700	$2,500–$4,500	12 years	Yes	Natural Gas, Propane	●●○
Navien	$1,075–$1,535	$3,900–$7,200	15 years	Yes	Natural Gas, Propane	●●●
Rheem	$300–$1,200	$1,800–$4,000	12 years	Yes	Natural Gas, Propane, Electric	●●○
Noritz	$600–$1,400	$2,500–$4,800	12 years	Yes	Natural Gas, Propane	●●○
Bosch	$500–$1,100	$2,200–$4,000	10 years	No	Natural Gas, Propane	●●○
EcoSmart	$150–$700	$300–$1,200	N/A	No	Electric	●○○

Your Situation	Best Brand	Why
Budget under $2,000 total installed	Rheem (gas) or EcoSmart (electric)	Widely available, competitive pricing, acceptable reliability for the budget
Gas whole-house, budget $2,000–$4,000	Rheem or Noritz	Strong mid-range options, good warranty, widely serviced
Gas whole-house, budget $4,000+	Rinnai	Best reliability track record, widest certified installer network, 12-yr HX warranty
Maximum efficiency, any budget	Navien	Highest UEF ratings, 15-yr HX warranty — but budget for complex installation
Electric whole-house	Rheem	Best balance of price, performance, and availability for whole-house electric
Point-of-use only	EcoSmart or Stiebel Eltron	Best range of small units; Stiebel Eltron for premium build quality

Tankless Water Heater Brands Compared: Cost, Reliability & Installation (2026)

Brand Comparison Table

Brand Profiles: Honest Assessments

Which Brand Is Right for Me?

Frequently Asked Questions