Updated October 2026 · 21 brands
Tankless water heater brands: every maker rated (2026)
There's no best tankless water heater brand, only better and worse models inside each line. Here are the 21 makers with three or more products in our catalogue, each with its best-rated heater and the rankings it makes.
Every brand, best-rated model first
Sorted by the rating of each brand's best complete heater, then by how many heaters we rate. Ratings come from buyer reviews and each listing's documented specs; we have not installed these units ourselves.
How to read a brand
Start from your fuel, not the logo. A brand that makes a great outdoor propane unit can sell a mediocre electric one, and the reverse. Then read the exact model: flow at your winter rise, input or kW, venting, warranty terms. Our tankless water heater rankings do that per fuel, and the comparison tool puts up to three models side by side.
Common questions
What is the best tankless water heater brand?
There isn't a single best brand: every maker here sells strong and middling models side by side, so we rate models. The best-rated heaters in our catalogue come from Rheem (Rheem 18 kW Electric, 240V, 9.3/10), MIZUDO (MIZUDO 199,000 BTU Natural Gas Indoor, 9.2/10) and WINTEMP (WINTEMP WN-36kW Electric, 240V, 8.1/10), and Rheem, MIZUDO, WINTEMP, Ranein, Stiebel Eltron, Rinnai, Westinghouse, APUS, CAMPLUX, Novieex and Takagi place at least one model in our top 5 rankings.
Which tankless water heater brands have the most models?
In our catalogue, Rheem (23 complete heaters), Rinnai (22 complete heaters) and Ranein (10 complete heaters) have the most. Rinnai (14), Rheem (10) and APUS (5) have the most heaters with a buyer review record.
Rinnai or Rheem: which tankless brand is better?
Neither across the board. We rate 22 Rinnai and 23 Rheem heaters; Rinnai's best-rated is the Rinnai RU199iN Condensing at 7.8/10, Rheem's the Rheem 18 kW Electric, 240V at 9.3/10. In our catalogue Rheem sells electric and gas units and Rinnai gas ones, so your fuel often decides before the logo does.
What is the most reliable tankless water heater brand?
We don't measure reliability, and no maker publishes failure rates we could compare. What you can compare is the warranty of the exact model (heat exchanger, parts and labor periods) and its buyer review record, both on each review page. Installation and descaling decide much of a tankless heater's life anyway.
Our 2026 rankings
#1: Rinnai RU199iN Condensing · 9.1/10Best High-Efficiency Condensing Tankless Water Heaters in 20265 models ranked
#1: MIZUDO 199,000 BTU Natural Gas Indoor · 9.2/10Best Tankless Water Heaters in 20265 models ranked
#1: Rheem 18 kW Electric, 240V · 9.3/10Best Whole-House Electric Tankless Water Heaters in 20265 models ranked
#1: FOGATTI Outdoor Propane Tankless · 9.1/10Best Outdoor Propane Tankless Water Heaters in 20265 models ranked#1: MIZUDO 199,000 BTU Natural Gas Indoor · 9.2/10Best Whole-House Tankless Water Heaters in 2026: Gas and Electric5 models ranked#1: MIZUDO 199,000 BTU Natural Gas Indoor · 9.2/10Best Gas Tankless Water Heaters in 20265 models ranked