Best Water Heaters 2026: Tankless, Gas, and Heat Pump Picks

Tankless is a simple promise: hot water that never runs out, from a box the size of a carry-on. The ECO 27 is the unit that made that promise mainstream on the electric side. Its 27 kW self-modulating design draws only the power the current flow demands, and at $393.36 verified it costs less than many people's last plumber visit.

The honest physics: electric tankless output depends on how cold your incoming water is. In Texas and the Sun Belt, where groundwater arrives warm, a 27 kW unit comfortably runs a shower and a sink together, and the ECO 27 earns its best-seller status. In Minnesota it becomes a one-fixture unit in January. Read our GPM explainer below, then our amperage explainer, before committing. If your panel checks out, nothing at this price competes. If it does not, the gas Rinnai V53DeN route below sidesteps the electrical question entirely.

If the ECO 27 is the value answer, the Tempra is the engineering answer. Stiebel Eltron is to electric water heating what Miele is to laundry: a German specialist that has been refining one product family for generations. The Tempra 24 Trend brings that pedigree at $619.99 verified.

The buying logic against the ECO 27 is pure philosophy. Same fundamental technology, same electrical demands, same endless hot water. The Stiebel premium buys build refinement and a brand with a century of institutional knowledge behind its support line. Budget rationalists take the EcoSmart and bank the $226; buy-it-for-life households take the Tempra and never think about it again. Bigger households in colder regions should look at the Tempra 36 Plus below instead.

The smartest tankless installs are often the small ones. Instead of one giant unit fighting the whole house's demand, a right-sized unit like the RTEX-13 serves one bathroom or one zone brilliantly, and its smaller electrical footprint means the panel conversation gets much easier than with the 27 kW monsters.

Rheem's brand is the other half of the story: this is the name on millions of American water heaters, with the parts availability and plumber familiarity that follow. At $287.00 verified it is the easy answer for the garage apartment, the cabin, or the workshop sink and shower. Whole-house shoppers should step up to the RTEX-24 or our top pick.

The ECO 18 exists for one buyer: the household whose electrical panel, not budget, is the constraint. Dropping from 27 kW to 18 kW meaningfully shrinks the breaker and wire demands, which can be the difference between a straightforward electrician visit and a panel upgrade quote.

A price quirk worth naming: at verified prices the ECO 18 ($407.37) currently costs slightly more than the ECO 27 ($393.36). Amazon pricing does this sometimes. If your panel can host the 27, buy the 27 and enjoy the headroom; the 18 is strictly the panel-constrained play, and a fair one, since a right-sized unit that installs cleanly beats a bigger one that triggers a service upgrade.

Rheem's pitch is not the spec sheet; it is the year-six service call. When a heating element or sensor eventually needs attention, the brand with parts in every supply house and a name every plumber knows becomes the easy unit to keep running. That is what $542.99 verified buys over the cheaper ECO 27.

Against the Stiebel Tempra 24, the RTEX-24 saves $77 and trades German refinement for American ubiquity. There is no wrong answer among the three whole-house electrics here; there is only which insurance you prefer, lowest price, deepest pedigree, or biggest service network. Rheem is the third option, and for many households the most practical one.

Cold groundwater is the enemy of electric tankless, and the Tempra 36 Plus is the biggest hammer available against it. Where a 27 kW unit in a northern winter becomes a single-shower machine, 36 kW keeps multi-fixture life plausible. At $630.70 verified, barely more than the Tempra 24, the capacity is nearly free at the register.

It is not free at the panel. This is the point in the guide where our amperage explainer below stops being advice and becomes the whole purchase decision: a unit this size can demand more capacity than an older service has to give. Electrician first, checkout second. If the answer is no, gas is your path: the Rinnai RX199iN delivers big-household hot water with zero panel drama.

The ECO 11 and the Rheem RTEX-13 above are the two ways to buy the same smart idea: put the heat where the water gets used. At $249.00 verified, the ECO 11 is the value pick of the pair, saving $38 against the Rheem for the same single-zone mission.

In a warm-groundwater climate this class of unit runs a full bathroom with ease, which is why the point-of-zone strategy is quietly the best hot water upgrade in sprawling single-story homes: no more marathon waits while cold pipe empties toward the far bathroom. Pick the EcoSmart for value, the Rheem for the service network, and either way size honestly: one zone per unit.

When the whole family showers back to back on a January morning, gas is still king. Electric tankless output rises and falls with groundwater temperature; a gas burner does not care. Rinnai has spent decades as the reference brand in this category, and the RX199iN is its current condensing flagship, extracting extra efficiency from exhaust heat that older non-condensing designs simply vent away.

The decision against our electric top pick comes down to climate, household size, and infrastructure: if you have a gas line, a cold winter, or three teenagers, the Rinnai premium buys certainty no electric unit at any price can offer, and our head-to-head below runs the full argument. If the flagship price stings, the V53DeN below is the value door into the same brand.

The cheapest thing about outdoor gas tankless is the installation you skip. Indoor gas units need sealed venting run through walls or roof, a significant chunk of any install quote. The V53DeN mounts on an exterior wall and vents to the air around it, which in mild-winter country turns a major project into a modest one.

At $741.65 verified you get Rinnai's burner pedigree in the value tier, a natural pairing with warm-climate homes where the outdoor mount thrives and warm groundwater means its capacity class covers real households. Northern buyers should spend up for the indoor RX199iN; this one belongs on a Texas wall.

Every other electric unit here makes heat; this one moves it, and that is why it wins the utility-bill decade. A heat pump water heater pulls warmth from the surrounding air into the tank, delivering hot water for a fraction of the running cost of resistance heating. Over a ten-year life, that difference commonly adds up to more than the unit's price.

The REHP50's Energy Star badge is also a key that opens incentive doors: federal efficiency tax credits and utility rebates frequently apply to this class, so your net price may land far below the $1,799.00 verified sticker. The trades are honest ones, finite tank capacity and the need for a reasonably warm host space. For a garage in Texas, it is close to a perfect appliance.

The most common hot water complaint in America is not capacity; it is the fifty-foot wait. Water cools in pipes between uses, so the distant sink runs cold for a minute while you pour the heater's work down the drain. A point-of-use mini-tank like the ES4 parks four hot gallons at the fixture, so the tap is hot the instant it opens.

At $259.00 verified, this is among the highest satisfaction-per-dollar purchases on this page, which its review scores reflect. It also pairs beautifully with any whole-house unit above: let the big system do volume while the Bosch kills the wait at the one stubborn sink. Renovating the kitchen anyway? Our shower head guide covers the other end of the hot water experience.

The POU 3.5 is the minimalist's answer to the same problem the Bosch solves: hot water where the pipes will not bring it fast. Being tankless, it never runs out and never stores a drop, which suits low-traffic sinks, cabins, and mobile setups where a mini-tank's bulk or standby heat makes no sense.

The choice against the Bosch ES4 is usage pattern. Busy family kitchen sink: the mini-tank's four-gallon punch wins. Occasional-use utility sink, shop basin, or RV: the EcoSmart's endless trickle and $73 savings win. Either way you are spending under $260 to end a daily annoyance, which is the best trade in home plumbing.