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EcoSmart is a US-based water heating brand best known for electric tankless water heaters and small electric mini-tank heaters. Unlike the gas-fired brands that dominate whole-home tankless conversations, the EcoSmart models covered here are all electric, which changes the decision from “where does the vent go?” to “how much electrical capacity does the panel have?” This guide walks through the EcoSmart models covered here, explains how the lineup is organized, and lays out what each one realistically fits. Everything below is based on the published product information for these models plus well-established general knowledge about electric water heating. Where a specification is not published, this guide does not guess at it.
How the EcoSmart lineup is organized
The models in this guide fall into three distinct groups, and mixing them up is the single most common sizing mistake homeowners make with this brand.
ECOS self-modulating tankless heaters. These are the higher-kilowatt units — the ECOS 18 (18 kW at 240 volts, 75 amps) and the ECOS 27 (27 kW at 240 volts, 112.5 amps). Both use EcoSmart’s patented self-modulating technology, which continuously monitors outlet water temperature and controls flow to hold the setpoint. EcoSmart states these units operate within one degree of the setpoint and are up to 96% thermal energy efficient, since they only heat water when there is a demand rather than maintaining a stored tank. Both share the same cabinet dimensions of 19 x 4.25 x 9.25 inches, which EcoSmart describes as roughly 90% smaller than a traditional tank heater and suitable for wall or point-of-use mounting.
Performance and POU units. The Performance 8 kW is a lower-output self-modulating tankless rated at 1.55 GPM, and the POU 6 is a 6 kW point-of-use heater designed for a single fixture. These are not whole-home devices. They exist to serve one tap or one low-flow fixture close to where the hot water is actually used, eliminating the long wait for hot water to travel from a distant heater.
ECO MINI plug-in mini tanks. The ECO MINI 1 (1.5 gallons) and ECO MINI 4 (4 gallons) are small stored-water heaters that plug into a standard 120-volt outlet and ship with an appliance line cord. EcoSmart positions both for buffer and point-of-use applications. A mini tank is a fundamentally different device from a tankless unit: it stores a small volume of already-hot water, so it delivers instantly at a single fixture but has a finite capacity before it needs to recover.
The models worth knowing
EcoSmart ECOS 27 (27 kW, 240V, 112.5 amps)
The ECOS 27 is the largest unit covered here. At 27 kilowatts it sits at the upper end of what residential electric tankless heaters are built to do, and in electric tankless design, kilowatts are what determine how much temperature rise you can hold at a given flow rate. The listing cites 2.7 to 6.6 gallons per minute depending on inlet water temperature, and describes the unit as suited to a bathroom, small sink, office breakroom or other point-of-use or low-flow application, with the usual electric-tankless caveat: the colder the incoming water, the lower the flow rate at which the unit can still deliver a comfortable outlet temperature. Warranty is listed as five years limited on leaks and one year on parts.
The limiting factor on this model is almost never the plumbing — it is the 112.5-amp draw. That is a serious load that typically requires multiple double-pole breakers, correspondingly sized conductors, and a service with genuine headroom after a load calculation. Whether a given home’s electrical service can support a 27 kW load is something only a licensed electrician’s load calculation can answer. Homes with warm inlet water, a larger service and few competing large loads are the most plausible candidates. If your panel is already near capacity, the cost and scope of the electrical work usually dominates the project.
- Endless On-Demand Hot Water; Consistent hot water when you need it that never runs out; Continuously monitored water temperature a…
- Save Energy; EcoSmart tankless electric water heaters are 96% thermal energy efficient; Only heats water when called unlike a tank…
- Save Space; EcoSmart tankless electric water heaters are 90% smaller than traditional tank heaters; may be installed on wall or at…
EcoSmart ECOS 18 (18 kW, 240V, 75 amps)
The ECOS 18 uses the same self-modulating control strategy, the same cabinet size, and the same stated warranty terms as the ECOS 27, but at 18 kilowatts and 75 amps. The published flow range is 1.8 to 4.3 gallons per minute depending on conditions — again, the high end of that range assumes warm incoming water and a modest temperature rise.
This is the model that fits a smaller, lower-simultaneous-demand situation: a one-bathroom home or apartment in a mild climate, a guest suite, an accessory dwelling unit, or a dedicated supply for a single bathroom group. It is also the more approachable option electrically, since 75 amps is a meaningfully smaller bite out of a residential service than 112.5 amps. Anyone considering either ECOS model should run the numbers on temperature rise before choosing, rather than assuming the published maximum flow applies to their climate.
- Endless On-Demand Hot Water; Consistent hot water when you need it that never runs out; Continuously monitored water temperature a…
- Save Energy; EcoSmart tankless electric water heaters are up to 96% thermal energy efficient; heats water on demand unlike a tank …
- Save Space; EcoSmart tankless electric water heaters are 90% smaller than traditional tank heaters; may be installed on wall or at…
EcoSmart POU 6 (6 kW point of use)
The POU 6 is purpose-built for a single point of use. EcoSmart describes it as designed for applications such as hand sinks in RVs, boats, restaurants, hotels, and medical offices, with low flow rates not exceeding 1 GPM. That framing is a useful honesty check: this is a hand-sink heater, not a shower heater.
Where it earns its place in a house is a remote bathroom, a workshop sink, a bar sink, or a garage utility sink that sits far from the main water heater. Serving that fixture locally avoids running a long hot line and avoids the water wasted waiting for hot to arrive. It fits best where the only demand is handwashing. Unlike the plug-in mini tanks, it is hardwired, and published sources differ on its voltage and amperage, so a licensed electrician should confirm the circuit against the manual and unit label.
- Designed for single point-of-use applications such as hand sinks in RVs, boats, restaurants, hotels, and medical offices requiring…
EcoSmart US Performance 8 kW (1.55 GPM self-modulating)
The Performance 8 kW is a self-modulating electric tankless unit rated at 1.55 GPM. It slots between the POU 6 and the ECOS models: more output than a hand-sink heater, far less than a whole-home unit. At 8 kilowatts, it is realistically a single-fixture or single-low-flow-fixture device, and the 1.55 GPM rating should be read as a flow ceiling that will tighten as inlet water temperature drops.
Reasonable uses include a laundry sink, a remote half bath, a utility area, or a single low-flow fixture in a mild climate. Treat 1.55 GPM as the planning number and compare it against the actual rated flow of the fixture it will serve. Unlike the plug-in mini tanks, an 8 kW tankless unit is hardwired and needs a dedicated 240-volt circuit, so it also calls for a licensed electrician; confirm the exact breaker size in the manufacturer’s manual.
- Brand New in box. The product ships with all relevant accessories
EcoSmart ECO MINI 4 (4-gallon, 120V)
The ECO MINI 4 stores four gallons and plugs into a 120-volt outlet, with an appliance line cord and a pressure relief valve included. EcoSmart lists it for buffer and point-of-use applications. Because it stores hot water rather than heating on demand, it delivers hot water immediately at the fixture it serves — the trade-off is finite capacity and a recovery period.
Typical fits are an under-sink installation in a kitchen or bathroom far from the main heater, a coffee station, or a buffer tank ahead of another appliance. Four gallons is enough for handwashing and dishes at a single sink, not for a shower. Note that even a plug-in unit still needs an outlet on a circuit that can carry it continuously, plus proper relief valve discharge routing.
- Plugs into 120V outlet
- Pressure Relief Valve Included
- For Buffer and Point of Use applications
EcoSmart ECO MINI 1 (1.5-gallon, 120V, 1440 W)
The ECO MINI 1 is the smallest unit in the group: 1.5 gallons of stored water, 1440 watts, 120 volts, with a digital output temperature display and an included appliance line cord. EcoSmart states it is manufactured in the United States and lists it, like the ECO MINI 4, for buffer and point-of-use duty. The product listing also carries a 99.8% energy efficiency claim, although the listing text attributes it to EcoSmart tankless heaters in general rather than to this stored-water model, so treat it with caution. As with any efficiency number, what it means for your utility bill depends entirely on your rates and how much hot water you actually draw.
This is the model for a single hand sink where space is tight — a powder room vanity cabinet, an office kitchenette, or a bar sink. Its compact footprint and plug-in installation are the main draws. With only 1.5 gallons stored, it should be matched to genuinely intermittent, low-volume use.
- Sleek and compact design with digital output temperature display
- ECOSMART tankless water heaters are 99.8-percent energy efficient
- Manufactured in United States
Model comparison
| Model | Type | Key capacity / output | Power | Best fit |
|---|---|---|---|---|
| ECOS 27 | Self-modulating electric tankless | 27 kW; listed 2.7–6.6 GPM depending on inlet water temperature | 240V, 112.5 amps | Largest electric tankless here; needs substantial service capacity |
| ECOS 18 | Self-modulating electric tankless | 18 kW; 1.8–4.3 GPM depending on conditions | 240V, 75 amps | Smaller homes, suites or single bathroom groups in mild climates |
| POU 6 | Point-of-use electric tankless | 6 kW; low flow not exceeding 1 GPM | Hardwired electric (confirm voltage and breaker size on the unit label and in the manual) | Single hand sink in a home, RV, boat or commercial washroom |
| Performance 8 kW | Self-modulating electric tankless | 8 kW; rated 1.55 GPM | Hardwired 240V-class electric (confirm breaker size in the manual) | One low-flow fixture such as a laundry or utility sink |
| ECO MINI 4 | 120V mini tank (stored) | 4 gallons; pressure relief valve included | 120V plug-in, line cord included | Under-sink point of use or buffer tank duty |
| ECO MINI 1 | 120V mini tank (stored) | 1.5 gallons; digital output temperature display | 120V, 1440 W plug-in, line cord included | Tightest spaces; intermittent single-sink use |
How to choose
Start with the electrical panel, not the plumbing. With electric tankless heaters, the kilowatt rating converts directly into amps, and the amps decide whether the project is straightforward or turns into a service upgrade. An 18 kW unit at 75 amps and a 27 kW unit at 112.5 amps are very different propositions for the same house. Have a licensed electrician perform a load calculation on your existing service before you commit to a model.
Then do the temperature rise math. Electric tankless output is a fixed amount of energy per minute; the flow you get is whatever that energy can raise to your target temperature. Northern homeowners with inlet water in the 40s see far lower usable flow than someone in a warm climate. Our tankless water heater size calculator walks through that calculation for both gas and electric units, and the broader comparison in best tankless water heaters, gas vs. electric explains why cold-climate whole-home conversions often end up on the gas side.
Decide whether you need whole-home or point-of-use. Many homeowners shopping EcoSmart do not actually need a whole-home replacement. If the real complaint is “it takes forever to get hot water at the far bathroom,” a POU 6, Performance 8 kW or an ECO MINI under that specific sink addresses the problem directly while the main heater keeps doing its job.
Tankless or stored? Tankless never runs out but is flow-limited. A mini tank is instant at the fixture but capacity-limited. For a hand sink used a few times an hour, a mini tank is often the simpler choice; for continuous low-flow draws, tankless makes more sense. If you are weighing the bigger picture of operating costs and replacement cycles, tankless vs. traditional water heater cost lays out the trade-offs, and the complete water systems guide covers how a heater fits with the rest of the plumbing.
Account for water quality. Scale is the main long-term enemy of any tankless heat exchanger. In hard-water areas, plan on periodic descaling and install isolation valves so the service can actually be performed.
Installation and safety
Electric water heaters look deceptively simple, and the high-kilowatt units are not DIY projects.
- Use licensed trades. Water heater replacement and installation generally require a licensed plumber, and the electrical hookup for a 240-volt tankless unit requires a licensed electrician. Where local code or the manufacturer’s warranty requires professional installation, using anyone else can void coverage.
- Pull permits. Permits and inspection requirements for water heater and electrical work vary by jurisdiction. Confirm what your local authority requires before work starts.
- Size the circuit properly. Breaker and conductor sizing, number of circuits, grounding and bonding must all follow the National Electrical Code and local amendments. A 112.5-amp or 75-amp draw typically means multiple dedicated double-pole breakers and a documented service load calculation. Never reuse an undersized existing circuit.
- Respect the relief valve. Stored-water heaters, including mini tanks, need a working pressure relief or T&P valve with discharge piped per code. Never cap, plug or block it.
- Plug-in does not mean unregulated. A 120-volt mini tank still needs a suitable outlet on an appropriately rated circuit, correct mounting support and proper drainage considerations for the space it sits in.
- Plan for freezing. Electric tankless units in garages, crawl spaces or unheated utility rooms are exposed to freeze damage. Our guide to winterizing your water heater covers the pre-winter checklist for both tank and tankless systems.
Frequently asked questions
Can an EcoSmart electric tankless unit replace my existing tank water heater?
Sometimes, but it depends on two things: your household’s peak simultaneous hot water demand and your electrical service capacity. The ECOS 27 and ECOS 18 are the largest units in this group, but their listings describe them for a bathroom, small sink or other point-of-use or low-flow applications rather than whole-home use, and both require significant dedicated amperage. In homes with cold incoming water and multiple bathrooms in use at once, a single electric tankless unit may not hold the flow you are used to. Get a load calculation and a temperature-rise estimate before deciding.
What does “self-modulating” actually mean?
Self-modulating means the heater adjusts its power draw and controls flow based on continuous monitoring of water temperature, rather than running full-on or fully off. EcoSmart states this holds the outlet temperature within one degree of the setpoint and avoids the energy used by a tank heater maintaining stored water around the clock. The ECOS 18, ECOS 27 and Performance 8 kW are all described as self-modulating.
Is an ECO MINI meant to be a whole-house water heater?
No. EcoSmart lists both the ECO MINI 1 and ECO MINI 4 for buffer and point-of-use applications. At 1.5 and 4 gallons respectively, they are designed to serve a single fixture, usually a sink, or to act as a buffer ahead of another appliance. They are not a substitute for a primary water heater.
How do these compare to gas tankless brands?
Electric and gas tankless units solve the same problem with different constraints. Electric units need no venting or gas line and are physically small, but they demand a lot of amperage. Gas units need venting, combustion air and correctly sized gas piping, but they generally deliver higher flow at a given temperature rise. If you are comparing across fuel types, see the Rinnai tankless buyer’s guide for the gas side of that comparison.
Specifications cited here come from the manufacturer’s published product information for these models. Confirm current specifications, warranty terms and code requirements with the manufacturer and your local licensed installer before purchasing.