Last updated October 4, 2026 — re-verified current Home Depot pricing directly; the AT-35WH-HD’s sale price moved from $89.99 to $119.99, and confirmed the PRO XTP is a distinct SKU from Atmor’s standard 36kW model (see naming note below).
Atmor shows up in tankless searches next to EcoSmart and Stiebel Eltron on price alone, and the hardware backs it up on paper — self-modulating output, digital temperature control, the same 240V multi-breaker installation pattern every whole-home electric brand uses. What’s easy to miss scrolling a product listing is the warranty gap: Atmor backs its units for 2 years on parts and workmanship, where the established electric brands on this site run 5 years or more. That’s not a reason to skip Atmor — it’s a reason to know exactly what you’re trading for the lower price before you buy.
A naming trap worth flagging: Home Depot lists two different Atmor 36kW units side by side — the standard AT-36WH-HD (two 40-amp double-pole breakers, ~$539.99) and the PRO XTP 36kW reviewed below (model AT-36N-XTP, four 40-amp double-pole breakers, roughly 150 amps of panel capacity). The “PRO” model is actually the cheaper of the two at $498.99, but it demands nearly double the electrical infrastructure — confirm the exact model number against your panel capacity before ordering either one.
Our top picks at a glance
| Model | Best for | Power | Max Flow | Circuit | Price |
|---|---|---|---|---|---|
| AT-35WH-HD | Single sink / point-of-use | 3,500W / 120V | 0.5 GPM | Standard 120V outlet | ~$119.99 |
| AT-29WH-HD | 2–3 bathroom whole-home | 29 kW / 240V | 5.4 GPM | 3x 40A double-pole | ~$474.99 |
| PRO XTP 36kW (AT-36N-XTP) | Larger home / cold climate | 36 kW / 240V | 7.03 GPM | 4x 40A double-pole (150A) | ~$498.99 |
| AT-36WH-HD (standard, not PRO XTP) | Larger home, less panel capacity | 36 kW / 240V | Lower rated flow than PRO XTP | 2x 40A double-pole | ~$539.99 |
Prices per Home Depot's current listings (re-verified October 2026): AT-35WH-HD $119.99 (marked down from $134.99 list), AT-29WH-HD $474.99 (marked down from $499.99), PRO XTP 36kW/AT-36N-XTP $498.99, standard AT-36WH-HD $539.99 (marked down from $599.99). Amazon, Lowe's, and Walmart pricing fluctuates and can run above or below these figures — check the retailer link before buying.
By the numbers
- 2 years — Atmor’s parts-and-workmanship warranty term, versus the 5-year parts terms Rheem, Rinnai, and Noritz attach to their whole-home electric or gas lines. — per Atmor’s published warranty terms
- 7 years — Atmor’s separate leak warranty, longer than its parts coverage but still shorter than the leak/heat-exchanger terms on the premium gas brands this site has reviewed. — per Atmor’s published warranty terms
- 3x 40A double-pole breakers — the electrical requirement for the 29 kW AT-29WH-HD at 240V, confirmed across Atmor’s own installation documentation and multiple retailer spec sheets — a real multi-circuit project, not a single-breaker swap.
- 4x 40A double-pole breakers (~150A) — what the PRO XTP 36kW (AT-36N-XTP) actually needs, versus just 2x 40A for Atmor’s own standard AT-36WH-HD 36kW model — nearly double the electrical infrastructure despite the PRO XTP costing $41 less at Home Depot. — per Home Depot and Atmor spec listings
1. Atmor AT-35WH-HD — Best Point-of-Use
Atmor AT-35WH-HD Point-of-Use Electric Tankless Water Heater
- Plugs into a standard 120V household circuit — no dedicated 240V line or electrician visit required for most installs, unlike every whole-home model on this list.
- Rated to 0.5 GPM, enough for one sink's worth of instant hot water but not a shower — pair it with our best point-of-use water heater roundup if you're comparing it against other single-fixture options.
- Home Depot has listed it as low as $119.99 (re-verified October 2026), marked down from a $134.99 list price, making it one of the cheapest tankless units this site has priced.
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A point-of-use unit like the AT-35WH-HD solves a narrower problem than a whole-home install: a detached sink, a workshop, a wet bar, or a guest bathroom too far from the main water heater to get fast hot water. Because it runs on a standard 120V outlet rather than a dedicated 240V circuit, it’s the rare tankless unit a confident DIYer can actually install without an electrician — just confirm local code allows a plug-in installation for the fixture you’re targeting.
2. Atmor AT-29WH-HD — Best Whole-Home (2–3 Bathrooms)
Atmor AT-29WH-HD Whole-Home Electric Tankless Water Heater
- 29 kW output and 5.4 GPM puts it in the same performance class as EcoSmart's ECO 27 and Rheem's RTEX-27, at a lower price than either.
- Requires three 40-amp double-pole breakers and three runs of 8/2 AWG wire at 240V — get an electrician's sign-off on panel capacity before ordering.
- Self-modulating technology adjusts power draw to actual demand, the same efficiency approach every electric tankless brand on this site uses.
The AT-29WH-HD is the Atmor most 2–3 bathroom homes land on, and at roughly $474.99 it undercuts comparably rated EcoSmart and Rheem units by a meaningful margin. The three-breaker install is the real cost most buyers underestimate — budget for an electrician’s time even if the unit itself is cheap, since a 29 kW draw is a genuine panel-capacity question, not a plug-and-play swap. See our best electric tankless water heater roundup for how it stacks up against the category leaders on warranty and long-term reliability.
3. Atmor PRO XTP 36kW (AT-36N-XTP) — Best for Larger Homes
Atmor PRO XTP Series 36kW Electric Tankless Water Heater
- 7.03 GPM is Atmor's highest residential flow rating, enough for a 4-bedroom home running multiple fixtures at once in a moderate climate.
- At roughly $498.99, it's barely more than the 29 kW model despite the higher output — but don't assume that means a lighter electrical install: it needs four 40-amp double-pole breakers and roughly 150 amps of panel capacity.
- Not to be confused with Atmor's separate standard AT-36WH-HD 36kW model (~$539.99), which actually requires fewer breakers (2x 40A) — the "PRO" name here refers to the self-modulating/digital-control hardware, not a smaller electrical footprint.
The PRO XTP 36kW is Atmor’s answer to homes where 29 kW is cutting it close — an extra bathroom, a cold-climate groundwater temperature, or just wanting headroom for two showers running at once. The price gap over the 29 kW model is small, but the electrical gap isn’t: confirm your panel has roughly 150 amps of spare capacity for four 40-amp double-pole breakers before ordering, since that’s nearly double what Atmor’s own standard 36kW model needs. For the broader electric-vs-gas tradeoff at this output level, see our electric vs gas tankless water heater comparison.
How to choose an Atmor tankless water heater
- One sink, no dedicated circuit available: the AT-35WH-HD — plugs into a standard outlet.
- 2–3 bathroom home, budget-conscious whole-home swap: the AT-29WH-HD.
- 4-bedroom home or colder climate, want flow headroom: the 36 kW PRO XTP.
- Weighing Atmor against Rheem or EcoSmart: expect to pay less for comparable self-modulating hardware, but budget for the shorter 2-year parts warranty when deciding how long you plan to keep the unit.
The bottom line
Atmor earns its shelf space at Home Depot and Lowe’s with real, self-modulating hardware at a lower price than the established brands: the AT-35WH-HD for a single point-of-use fixture, the AT-29WH-HD for a typical 2–3 bathroom whole-home install, and the PRO XTP 36kW (AT-36N-XTP) for larger homes or colder climates — just confirm you’re ordering that exact model and not Atmor’s separate standard AT-36WH-HD, since the two 36kW units need different breaker counts. The tradeoff is a 2-year parts warranty instead of the 5-year terms Rheem and Rinnai offer, so weigh the savings against how long you expect to own the unit. A newer Amazon-only rival at an even lower price is Midea, whose 18kW MHE18W2AWW has listed as low as $250–$270 with WiFi control but only a 1-year warranty, half of Atmor’s own 2-year term — see our Midea tankless water heater review for both current models. For the full field of electric options at every price point, see our best electric tankless water heater roundup, or start with our best tankless water heater guide to compare every brand side by side.