Quick Answer: State Water Heaters is A.O. Smith’s contractor-channel brand — literally the same hardware platforms as A.O. Smith’s own tankless lineup, sold under a different badge through plumbing wholesalers instead of retail. The ProLine XE GTS-540-NIH (199,000 BTU, indoor condensing) is the best overall pick at $1,874.00 (HVACDirect.com, checked August 2026). For hard-water homes, the GTS-240X3-PIH (160,000 BTU propane, condensing, X3 Scale Prevention) runs $1,295.00 (AC Wholesalers, checked August 2026). For a no-venting point-of-use install, the UPVS-90E (9 kW, 240V) shares its exact platform with A.O. Smith’s UPVA-90E, priced at $279.72 on SupplyHouse under that badge. The detail that matters most before you buy: State is a wholesale-first brand, so budget for a contractor relationship rather than a big-box pickup.
A.O. Smith owns more water heater badges than most shoppers realize — State, American Water Heater, and Lochinvar all sit under the same corporate roof, and our A.O. Smith roundup covers the retail-facing name. State is the trade-channel sibling: the same core gas and electric platforms, rebadged, sold almost exclusively to and through licensed contractors. That’s a different story from Bradford White, a genuinely separate manufacturer that also happens to be trade-only — with State, you’re buying A.O. Smith engineering under a different label, which changes how you should shop for it.
Our top picks at a glance
| Model | Best for | Type | BTU/kW | UEF | Price |
|---|---|---|---|---|---|
| GTS-540-NIH | Best overall | Gas condensing, indoor | 199,000 BTU | 0.95* | $1,874.00 |
| GTS-240X3-PIH | Best for hard water | Propane condensing, X3 | 160,000 BTU | 0.94 | $1,295.00 |
| UPVS-90E | Best electric, no venting | Electric point-of-use | 9.00 kW | N/A | ~$280 (shared platform) |
*GTS-540-NIH’s UEF is reported for the shared-platform A.O. Smith ATI-540H-N; State’s own listings don’t republish the figure separately. Prices are equipment-only, wholesaler listings checked August 15, 2026 — installed totals run higher once labor, venting (gas models), or a dedicated circuit (electric models) are added, per our tankless water heater cost guide.
The badge-sharing most shoppers never notice
Search “State vs A.O. Smith tankless” and the pattern isn’t subtle once you compare model numbers side by side. State’s GTS-510CX3-110 (indoor, non-condensing, X3 Scale Prevention, 10.0 GPM continuous flow) and A.O. Smith’s ATI-510CX3-110 are the same unit, down to the spec sheet. The point-of-use electric line goes a step further: the 9 kW/240V single-chamber unit ships as State’s UPVS-90E, A.O. Smith’s UPVA-90E, and American Water Heater’s UPVM-90E — three badges, one manufacturer, one factory in Ashland City, Tennessee. A.O. Smith bought State Industries, Inc. outright in 2001 for $58 million, and the badge-sharing you see today is what that integration looks like two decades later.
By the numbers
- $58 million — what A.O. Smith paid to acquire State Industries, Inc. in 2001, the deal that folded State into the same manufacturing operation behind A.O. Smith-badged units today.
- Up to 300% longer heat-exchanger life claimed for X3 Scale Prevention Technology on State’s GTS-240X3-PIH product page — the identical claim A.O. Smith makes for the same tech on its own Adapt+ line, since it’s the same underlying hardware.
- 3 brand badges, 1 platform — the 9 kW/240V point-of-use electric unit ships as State’s UPVS-90E, A.O. Smith’s UPVA-90E, and American Water Heater’s UPVM-90E, confirming how far the shared-hardware strategy extends across A.O. Smith’s brand portfolio.
1. ProLine XE GTS-540-NIH — Best Overall
State ProLine XE GTS-540-NIH
- Runs the same 199,000 BTU condensing core as A.O. Smith's ATI-540H-N, State's trade-channel take on that platform — confirm current wholesaler pricing before assuming either badge is the cheaper route, since it varies by distributor.
- No X3 Scale Prevention on this non-X3 "540" tier — if you're in a hard-water region, the smaller GTS-240X3-PIH below carries the upgrade, or plan for a dedicated scale-inhibitor filter and stricter descaling schedule.
- Indoor condensing installation with PVC venting — check clearance in your mechanical room against our [sizing guide](/guides/tankless-water-heater-sizing/) before ordering.
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For a straightforward whole-home indoor swap, this is State’s core condensing platform at wholesale pricing — the same engineering as A.O. Smith’s retail-available ATI-540H-N, sourced through a contractor-first channel instead.
2. ProLine XE GTS-240X3-PIH — Best for Hard Water
State ProLine XE GTS-240X3-PIH
- X3 Scale Prevention Technology is built in — State's own spec sheet claims up to 300% longer heat-exchanger life versus an unprotected unit, the same platform tech A.O. Smith uses on its Adapt+ flagship.
- 0.94 UEF condensing efficiency, sized for a 2-bath home in northern climates or a 3-bath home in southern climates per State's own capacity guidance — confirm your fixture count against our [sizing guide](/guides/tankless-water-heater-sizing/) rather than assuming the BTU rating alone covers you.
- This same X3 platform is also licensed to Takagi (badged as the TK-240X3-PIH) and sold under American Water Heater's badge (GT-240X3-PIH) — one more confirmation of how far the shared-hardware strategy runs in this corner of the industry.
If hard water is the concern driving your search, this is the State model to compare against A.O. Smith’s Adapt+ ATHR-199X3 — same core scale-prevention tech, smaller BTU tier, lower price. Pair it with our descaling guide regardless of which badge you buy.
3. UPVS-90E — Best Electric, No Venting Required
State UPVS-90E
- Wall-mounts on standard NPT connections with no gas line, venting, or combustion air — the fastest install path in State's lineup, meant for a single fixture or small point-of-use load rather than whole-home service.
- State's own site doesn't publish a distributor price for the UPVS-90E specifically, but the identical 9 kW/240V unit sells for $279.72 under A.O. Smith's UPVA-90E badge on SupplyHouse.com (checked August 2026) — a reasonable price anchor since it's confirmed the same hardware.
- For whole-home electric coverage instead of point-of-use, this small single-chamber unit isn't sized for it — see our [best electric tankless water heater](/best/best-electric-tankless-water-heater/) roundup for higher-kW options built for that load.
For a single remote bathroom, workshop sink, or other point-of-use load where running gas isn’t worth it, this is State’s simplest install — no venting, no combustion air, just a 240V circuit.
How to choose
- If you want State’s core whole-home gas platform: the GTS-540-NIH — 199,000 BTU condensing, no X3 markup.
- If you’re in a hard-water region: the GTS-240X3-PIH — built-in X3 Scale Prevention at a lower price than the bigger non-X3 unit.
- If you need a single point-of-use fixture covered without venting: the UPVS-90E — smallest, simplest install in the lineup.
- If you want the same hardware sold through a retail-friendly channel instead: see our A.O. Smith roundup — same platforms, different badge, some models on Lowe’s and Amazon.
The bottom line
State isn’t a competitor to A.O. Smith so much as its trade-channel alter ego — same corporate parent since a 2001 acquisition, same core gas and electric platforms, badge-shared three ways in the case of the point-of-use electric line. The GTS-540-NIH ($1,874.00) is the strongest whole-home pick, and the GTS-240X3-PIH ($1,295.00) is the one to reach for in hard-water territory. What actually differs from A.O. Smith isn’t the engineering — it’s the channel: budget for a plumbing wholesaler and a contractor relationship, not a big-box aisle.