10 Best Electric On Demand Water Heater 2025 in the United States

The Stiebel Eltron Tempra 24 Plus is a solid choice for anyone looking for an electric on-demand water heater, particularly for households that require continuous hot water. One of its standout features is the advanced flow control technology that consistently maintains water temperature, ensuring that your hot showers are uninterrupted. This model has a powerful capacity of 24 kW, making it suitable for larger homes, and it can heat water up to 140°F, which is adjustable to prevent scalding.

Its compact design is another advantage, allowing it to fit in tight spaces without requiring venting, which can simplify installation. Additionally, the unit is designed for energy efficiency, and features like auto-modulation help to save on energy costs. The savings monitor is a nice touch, showing users how much they save on their bills, which can be a significant advantage in the long run.

On the downside, the Tempra 24 Plus does require a higher electrical service of at least 150 amps, which could mean additional installation costs if your current system needs upgrading. While the unit is generally quiet, some users may find that it slightly reduces the water flow when demand exceeds its capacity, which could be an issue during peak usage times. The warranty provided is commendable, with a 7-year leakage and a 3-year parts warranty, giving buyers some peace of mind regarding reliability.

The Rheem 18kW 240V Tankless Electric Water Heater is a solid option for those looking to efficiently supply hot water on demand. With a flow rate of up to 4.4 gallons per minute (GPM), it can cater to smaller households or applications requiring moderate hot water supply, making it ideal for apartments or homes with limited space.

One of its strengths is the 99.8% energy efficiency, which means it consumes less energy compared to traditional water heaters. This can help save on electricity bills over time. The unit features an external digital thermostatic control with an LED display, allowing users to set temperatures with +/- 1 degree accuracy, which is a handy feature for precise control and comfort. The self-modulating technology adjusts the power based on the demand for hot water, ensuring consistent performance. Additionally, the durable copper immersion heating elements are field-serviceable, which can simplify maintenance and repair.

However, there are some limitations to consider. The maximum flow rate of 4.4 GPM may not be sufficient for larger households or simultaneous high-demand situations, such as running multiple showers at once. Also, while the installation is straightforward with bottom water connections, it may still require professional assistance for optimal setup, especially for those unfamiliar with plumbing. It’s also worth noting that while the product dimensions are compact (14.5 inches wide and 18.25 inches high), its wall-mounted design might not suit every installation preference.