10 Best Booster For Water Heaters 2025 in the United States

The Stiebel Eltron Tempra 24 Plus is a tankless water heater that caters to users seeking a continuous hot water supply without the interruption of traditional heaters. Its advanced flow control technology ensures a consistent temperature, making it suitable for households needing reliable hot showers. The compact design is a space saver and eco-friendly, as it includes auto-modulation to manage energy usage efficiently.

With a 24kW power rating and a wide output range from 68°F to 140°F, it is versatile for different household needs. However, it requires a significant minimum electric service of 150 A, which might be a drawback for homes not equipped to handle such a load. The installation could also require professional assistance, adding to the initial cost. Safety is addressed with options to limit maximum water temperature, preventing scalding risks. Additionally, with warranties covering leakage and parts, it promises durability and reliability.

The LED display and user-friendly controls enhance its usability. Despite its higher initial installation requirements, its energy-saving benefits could lead to reduced costs in the long run. This model is ideal for those prioritizing energy efficiency and consistent hot water delivery for a whole house, assuming their electrical setup meets the requirements.

The Rheem RTEX-36 36kW Electric Tankless Water Heater is a robust choice for those seeking a powerful and efficient booster for their water heating needs. With a power rating of 36 kW and a maximum flow rate of 6 gallons per minute, it can comfortably serve households with moderate hot water demands. The model operates at 240 volts, making it suitable for most residential installations.

One notable strength of this unit is its energy efficiency, boasting a 99.8% efficiency rate, which means lower energy bills and a greener footprint. Additionally, the digital temperature control allows for precise adjustments, ensuring the water temperature is always just right. Its compact and stylish design also makes it a good fit for spaces where aesthetics are a consideration.

However, there are some points to consider before purchasing. The installation requires a 240V electrical connection, which might not be available in all homes without some electrical upgrades. While its flow rate is adequate, it might fall short for larger households or those with high simultaneous hot water usage. Safety features are not elaborated upon, so it's important to ensure that the unit complies with your local safety standards. Customer feedback is generally positive, with a 4.4 out of 5-star rating, indicating user satisfaction, but the sample size is quite small. This water heater is well-suited for medium-sized households looking for an efficient and stylish unit, but make sure your home meets the necessary electrical requirements for installation.

The EcoSmart ECOS 27 is a tankless electric water heater with a substantial power rating of 27 kW at 240 volts, which means it can handle multiple low-flow applications simultaneously, such as a bathroom and a small kitchen sink. Its self-modulating technology is a notable strength, as it adjusts energy use based on hot water demand, making it highly energy efficient—claimed to be up to 96% thermal energy efficient. This feature can significantly save on energy costs compared to traditional tank heaters that continuously maintain water temperature.

Despite its efficiency, the maximum flow rate of 6.6 gallons per minute may not suffice for larger households with high simultaneous water usage, making it more suitable for smaller homes or specific point-of-use applications. Additionally, the temperature rise capability might be limited in extremely cold climates.

The compact size is a strong advantage, allowing the unit to be wall-mounted, thus saving considerable space compared to bulky tank heaters. With dimensions of 19 x 4.25 x 9.25 inches, it can fit in tight spaces, which is ideal for apartments or offices with limited installation areas. Safety features, while not extensively detailed, seem to be embedded through the consistent monitoring of water temperature, although potential buyers might want to confirm specific safety certifications if this is a primary concern.

Installation requirements should be carefully considered as the unit demands a 240-volt connection and 112.5 amps, which might necessitate electrical upgrades in older homes. While the product offers a five-year limited warranty on leaks, and one year on parts, it's advisable to review warranty conditions to understand coverage fully.

The EcoSmart ECOS 27 serves well as an efficient and space-saving booster for water heaters, especially suited for smaller or specific-use scenarios, but may not be the best fit for high-demand households.