10 Best Compact Tankless Electric Hot Water Heaters 2025 in the United States

The EcoSmart ECOS 27 tankless electric water heater is a compact and efficient option for those needing hot water on demand, especially in smaller spaces like bathrooms, offices, or kitchen sinks. It delivers between 2.7 and 6.6 gallons per minute depending on your incoming water temperature, which is suitable for low to moderate hot water use but might struggle with multiple large fixtures running simultaneously. Its 27 kW power rating at 240 volts ensures a strong temperature rise up to 140°F, and the self-modulating technology helps keep the temperature steady within 1 degree of your setting, improving comfort and saving energy. Speaking of energy, it’s very efficient—about 96% thermal efficiency—because it only heats water when you need it, unlike traditional tank heaters that keep water hot all the time.

The heater is also quite small, about 19 by 9.25 by 4.25 inches, and mounts easily on a wall, making it a great space saver. Installation is straightforward, but keep in mind it requires a substantial electrical supply (112.5 amps) which might need an upgrade to your home’s electrical panel. Warranty coverage includes 5 years limited on leaks and 1 year on parts, which is decent but not the longest in the market. If you want an energy-saving, space-saving water heater for light to moderate use, the EcoSmart ECOS 27 fits well. However, it may not be ideal for larger households or high-demand situations where more flow or multiple simultaneous hot water uses are needed.

The EcoSmart ECO 27 is a compact, wall-mounted electric tankless water heater that stands out for its high power rating of 27 kW, which allows it to deliver a maximum flow rate of about 6.6 gallons per minute. This means it can supply enough hot water for multiple bathroom fixtures simultaneously in small to medium homes, making it suitable if you want a reliable flow without a bulky tank. It uses 240 volts on a single phase and offers digital temperature control with an easy-to-read LED display, so adjusting hot water temperature up to 120°F is straightforward. The heater is quite space-efficient with dimensions of 17 by 17 by 3.5 inches and weighs just under 11 pounds, which makes installation feasible in tight spots, especially compared to traditional tank water heaters. Energy efficiency is a strong point here; as a tankless unit, it heats water on demand, helping reduce energy waste and utility bills. EcoSmart backs this model with a limited lifetime warranty on key electronic components and heating elements, though the warranty doesn’t cover labor or incidental costs and requires proper registration to remain valid.

One limitation is that the maximum temperature is capped at 120°F, which might be lower than some users expect for specific needs. Also, while the flow rate is good for many households, it might be insufficient for larger homes with higher simultaneous hot water demands. The EcoSmart ECO 27 represents a smart choice if you want compact size, energy-efficient electric heating, and moderate hot water flow, but it may not be the best fit if you need very high temperature settings or serve a larger family with heavy water usage.

The Orbek 14kW tankless electric water heater provides instant hot water with a flow rate of up to 3.38 gallons per minute, suitable for 2 to 3 points of use simultaneously, such as sinks or showers. It includes a stable temperature control system that maintains water temperature within 1°F of the set level, adjustable between 86°F and 140°F through an easy-to-read LED display. Designed for high energy efficiency, it can reduce electricity costs by up to 60% compared to traditional tank heaters, utilizing water-electricity separation technology that also helps prevent scaling and corrosion.

This heater requires a 240V power supply and a dedicated 60-amp breaker, which may necessitate professional electrical installation if your home’s setup is insufficient. Its compact size (approximately 14 by 9.5 inches) saves space, making it ideal for tight installation spots. Safety features include ETL certification and multiple protections against leaks, overheating, dry heating, and electrical issues. The product comes with a warranty and 24/7 customer support for added peace of mind.

Its 14kW power rating limits its use to smaller households or point-of-use applications rather than whole-home coverage. Due to specific electrical requirements and installation considerations, it may not be suitable for those seeking a simple DIY installation or with lower electrical capacity. This model fits well for users needing reliable, energy-efficient instant hot water for a few taps or showers, who have the appropriate electrical setup and want a space-saving solution with modern controls.