Electric Mini Tank Water Heater UL Listed
- Water Heater
- More reviewed than 60%
The Incoloy heating element and thick insulation make this a durable-leaning pick for one sink, provided the 1/2 inch fitting matches your lines.
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How it ranks among the 10 water heaters we track
4.3★ across 764 Amazon ratings, Bayesian-smoothed toward the category average.
764 Amazon ratings, weighted on a log scale so huge counts don't drown everything.
100+ bought on Amazon last month.
Brand identity, imagery, description and spec coverage.
The ProductDome score is separate from the Amazon rating shown above: it combines the Bayesian-smoothed Amazon rating with evidence volume, tracked demand, and data quality across the 10 water heaters we track - how the scorecard works · full water heaters data report. Confidence: limited - incomplete product information.Updated 8 days ago. Data-computed, not a hands-on test. Compiled by the ProductDome Research Team.
Overview
Thermomate's ES250 packs a 2.5-gallon tank into a compact cube meant to live under a sink, counter or cabinet and supply hot water to that single fixture on its own 120-volt circuit.
It uses a 3-layer, porcelain enamel glass-lined tank and an Incoloy 800 stainless steel heating element rather than the more common copper element, a spec Thermomate ties to better corrosion resistance and a 99 percent heating efficiency figure. At 30mm, the insulation is on the thicker side for this size class, which should help it hold temperature longer between draws. The 1/2 inch NPT connection is narrower than some competing 2.5-gallon units that use 3/4 inch, worth checking against existing supply line fittings before buying.
- 2.5-gallon tank, 1440W at 120V
- Incoloy 800 stainless heating element
- 50-149 F adjustable thermostat
- UL listed, 150 PSI max
Who it's for
Works for a single remote sink, RV galley, salon station or shop washroom needing a small, self-contained hot water supply. Not intended to serve more than one fixture.
Strengths and trade-offs
Drawn from this product's published specifications.
- Incoloy 800 heating element resists corrosion better than copper
- 30mm insulation for better heat retention
- UL listed with ASME/ANSI/CSA-approved T&P valve
- Compact 12.95 inch cube fits tight spaces
- 1/2 inch NPT connection may need adapting to 3/4 inch lines
- Only 1-year warranty on parts versus 3 years on the tank
- 2.5 gallons limits it to one fixture at a time
Performance notes
The Incoloy 800 heating element is the standout spec here: Thermomate rates it as four times more corrosion resistant than copper and more efficient under high temperature and pressure, which should extend service life versus a basic copper-element tank. The 3-layer glass lining and extra-thick anode rod target scale and rust inside the tank itself, and the unit is rated to withstand 10,000 impulse cycles in testing. Thermostat range runs 50 to 149 F, with a 150 PSI maximum pressure and a UL-listed T&P relief valve for overpressure protection.
Specifications
| Brand | thermomate |
|---|
Other thermomate water heaters
How it compares
This product against the closest alternatives we track in water heaters.
| Product | Amazon rating | Ratings | ProductDome score |
|---|---|---|---|
| Electric Mini Tank Water Heater UL ListedThis product | 4.3 / 5 | 764 | 2.7 / 5 |
| Stiebel Eltron 233219 2.5 gallonStiebel Eltron | 4.6 / 5 | 462 | 4.2 / 5 |
| CAMPLUX 5L Portable Tankless Water HeaterCamplux Enjoy Outdoor Life | 4.2 / 5 | 3,346 | 4.1 / 5 |
| EcoSmart ECO 8 Tankless Water HeaterEcoSmart | 4.2 / 5 | 709 | 4.0 / 5 |
| GASLAND BS158 Outdoor Portable Gas Water Heater 1.58GPMGasland | 4.3 / 5 | 1,400 | 3.9 / 5 |
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Questions about the thermomate water heaters
Common buyer questions answered straight from the product spec data - no fluff, no "it depends".
What size water connection does the ThermoMate ES250 use?
It uses a 1/2 inch NPT water connection, narrower than the 3/4 inch fitting on some other mini tanks in this size range.
How long is the warranty?
Thermomate covers the tank for 3 years and parts for 1 year, with 24-hour customer service listed.
What are the dimensions and weight?
It measures 12.95 x 12.95 x 11.5 inches and weighs 15.4 pounds, sized to mount under a sink, counter or cabinet.