Searching “Costco tankless water heater” turns up something different from every other big-box retailer on this site: there’s no product page to add to cart. Costco routes tankless water heaters through its member Home Services program instead of its warehouse floor, and that changes what you’re actually comparing when you shop there. Here’s how the program works and where it wins or loses against buying a unit yourself.
How the Costco program differs from a shelf purchase
| Costco program | Home Depot / Lowe's | |
|---|---|---|
| Brand choice | Rheem only | Multiple brands (Rheem, Rinnai, Navien, A.O. Smith, EcoSmart, Bosch) |
| How you buy | Free consultation → sized quote → bundled install | Buy the unit (in-store or online), arrange install separately or via retailer's contractor network |
| Published price | None — quote-only, sized to your home | Listed unit price, install quoted separately |
| Warranty | 12-year parts and labor (program-specific) | Manufacturer standard, typically 5-15 years depending on brand/model |
| Member incentive | Up to $300 Costco Shop Card | Store-specific promotions and rebates vary |
Program terms per Costco's published water heater services page as of September 2026; installer network coverage and current Shop Card promotions vary by region and can change without notice, so confirm at consultation.
By the numbers
- 12 years — the parts-and-labor warranty term commonly attached to a Costco-program Rheem tankless install, roughly double the 6-year term typical of the same class of unit bought and self-installed. — per Costco’s water heater services program terms
- $300 — the maximum Costco Shop Card credit offered with a completed Rheem water heater installation through the program, applied after the job closes rather than off the quoted price. — per Costco member services program
- 1 — the number of brands available through Costco’s tankless program (Rheem), versus 5-6 brands stocked at Home Depot or Lowe’s — the clearest trade-off for the bundled warranty and incentive.
Rheem Condensing Gas Tankless — Costco’s Program Platform
Rheem Condensing Gas Tankless (Costco installation program)
- Costco's program draws from Rheem's condensing platform — the same general hardware family covered in depth in our Rheem tankless lineup guide, including the IKONIC and Performance Platinum lines sold under different names at other retailers.
- Because Costco quotes a sized install rather than a fixed SKU, the exact model and GPM rating you get depends on your home's bathroom count and gas-line capacity — ask the installer to name the specific model so you can cross-check its spec sheet independently.
- If you want to shop the same Rheem hardware on your own terms — different GPM tiers, your own installer, and a comparison against Rinnai or Navien — start from our best tankless water heater roundup instead.
Get your tankless heater and fittings in two days — try Amazon Prime free for 30 days.
What the bundled price doesn’t tell you upfront
Two things are worth clarifying before you book a Costco consultation:
- You can’t comparison-shop the unit price in advance. Every other retailer on this site lists a sticker price you can check against Amazon or a plumbing wholesaler before you buy. Costco’s program only produces a number after an installer has sized your home, so the first real price comparison you can make is Costco’s quote against an independent plumber’s quote on the same Rheem model — get both before signing.
- The warranty is tied to the program, not the box. A 12-year parts-and-labor term sounds like a clear win over Rheem’s standard 6-year coverage, but it only applies to units installed through Costco’s program. Buying the same Rheem platform elsewhere and hiring your own plumber reverts you to Rheem’s standard warranty tiers — covered in detail in our tankless water heater warranty guide.
The bottom line
Costco isn’t a place to buy a tankless water heater the way you’d buy one at Home Depot or Lowe’s — it’s a bundled Rheem installation program, single-brand, quote-only, but backed by a genuinely longer 12-year warranty and a member Shop Card incentive that can offset a meaningful chunk of the job. It’s worth a consultation call if you’re not set on a specific brand and want one company to handle sizing and installation together — just get an independent plumber’s quote on the same class of unit before you commit, since there’s no shelf price to check the Costco number against. For every brand ranked side by side if you’d rather shop and install on your own terms, see our best tankless water heater guide.