Find the Best Tankless Water Heater for Your Home
We compare and rank gas, propane, and electric tankless water heaters on flow rate, efficiency, and real install cost — so you get endless hot water without the guesswork.
Latest Reviews & Guides
Tankless Water Heater Buffer Tank (2026): What It Actually Is, and What Most Homes Should Buy Instead
A 'buffer tank' for a tankless water heater usually means a 25-300 gallon commercial ASME component, not an Amazon purchase. We explain what really solves short-cycling for a home — Navien's built-in buffer or a flow-through mini-tank like the Bosch ES4 — and when you genuinely need the commercial version.
Best PicksTankless Water Heaters at Walmart (2026): Why You Won't Find One on the Shelf
Walmart sells tankless water heaters under the real Rheem RTEX pro-channel name instead of Home Depot's retail-renamed RETEX/ECOH line — but you won't find one in a Walmart aisle. Real prices, the online-only/marketplace mix, and the major-appliance return catch.
Best PicksTankless Water Heaters at Menards (2026): Three Brand Tiers Under One Roof, Plus the 11% Rebate Explained
Menards sells tankless water heaters under three different badges — Richmond, Rheem Prestige, and State — plus a mail-in 11% rebate that Home Depot and Lowe's don't offer. Real prices, the return-window fine print, and why the State GTS-540-NIH beats the equivalent Rheem on price and warranty.
Best PicksTankless Water Heaters at Costco (2026): Why You Can't Just Put One in Your Cart
Costco doesn't sell tankless water heaters off the shelf — it runs an exclusive Rheem installation program with a 12-year warranty and up to a $300 Shop Card. Here's how the Costco path actually works, and how it compares to buying a unit yourself.
Best PicksTankless Water Heaters at Lowe's (2026): What's on the Shelf, and Why the Return Window Is Shorter Than You'd Guess
Lowe's stocks A.O. Smith, Rinnai, EcoSmart, and Bosch tankless water heaters — but its return policy on an installed or opened unit is meaningfully stricter than Home Depot's. Real brands, real prices, and the fine print.
Best PicksTankless Water Heaters at Home Depot (2026): What's Actually in Stock, and What a Discounted Price Doesn't Cover
Home Depot sells Rinnai, Rheem, Navien, Bosch, EcoSmart, and Camplux tankless water heaters online and in-store — but its own installation service and 90-day return window work differently than buying through a plumber. Real prices, brand availability, and the fine print.
Why Trust TanklessHeaterLab?
Spec-Driven Reviews
We rank on measured GPM flow rate, UEF efficiency, and real-world install cost — not marketing claims.
Tankless Specialists
Gas, propane, condensing, and electric on-demand units — we know Rinnai from Rheem and UEF from GPM.
Every Budget
From under-$200 point-of-use electric units to premium condensing whole-home systems — clearly labelled.
Updated for 2026
Prices, picks, efficiency ratings, and tax-credit notes kept current.