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

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Our Top Picks

#1

Winner

Stiebel Eltron Tankless Water Heater - Tempra 29 Trend – Electric, On Demand Hot Water, Eco, White

Rating
9.9
Chosen by1,483
Flow Rate
Temperature Rise
Power Rating

Most important from
2063 reviews

Flow Rate
Provides a continuous flow of hot water, even when running two showers simultaneously.
Temperature Rise
Temperature control is precise, ensuring hot water without any fuss.
Power Rating
Uses no power when not in use, providing instant hot water upon return.
Energy Efficiency
The unit's performance has exceeded expectations in terms of convenience and efficiency.
Size and Installation
The installation took about four hours, including the addition of a whole-home water filtration system.

The Stiebel Eltron Tempra 29 Trend is a compact and energy-efficient tankless electric water heater that's great for providing continuous hot water on demand. Its sleek white design makes it a space saver, fitting well in tight spaces and eliminating the need for venting. With a powerful 28.8 kW rating, it delivers an impressive water temperature range from 68°F to 140°F, ensuring hot showers whenever needed without interruption.

The digital temperature display is user-friendly, and the unit operates silently, which is a plus for households looking to minimize noise. Additionally, the auto-modulation feature helps save energy by adjusting the power based on water demand, making it eco-friendly. The solid copper heating system adds to its durability and reliability.

The 7-year leakage warranty and 3-year parts warranty offer peace of mind and reflect the brand’s confidence in the product's quality. However, it’s essential to note that the unit requires a minimum electrical service of 200 A, which might be a consideration for homes with lower electrical capacity. If you have the appropriate electrical setup, the Tempra 29 Trend is a robust option for consistent and efficient hot water supply in your home.

Rating
9.9
Chosen by1,483
Flow Rate
Temperature Rise
Power Rating

Most important from
2063 reviews

Flow Rate
Provides a continuous flow of hot water, even when running two showers simultaneously.
Temperature Rise
Temperature control is precise, ensuring hot water without any fuss.
Power Rating
Uses no power when not in use, providing instant hot water upon return.
Energy Efficiency
The unit's performance has exceeded expectations in terms of convenience and efficiency.
Size and Installation
The installation took about four hours, including the addition of a whole-home water filtration system.
#2

Stiebel Eltron Tankless Water Heater – Tempra 24 Plus – Electric, On Demand Hot Water, Eco, White, 20.2

Rating
9.8
Flow Rate
Temperature Rise
Power Rating

Most important from
2063 reviews

Flow Rate
Ability to provide a continuous flow of hot water even when running two showers simultaneously.
Temperature Rise
Accurate temperature control ensures you get the hot water you desire without any fuss.
Power Rating
Using no power when not in use, and delivers instant hot water upon return.
Size and Installation
Impressively quiet and space-saving design is a game-changer.

The Stiebel Eltron Tempra 24 Plus tankless electric water heater is designed to deliver continuous on-demand hot water for your entire household. With its advanced flow control technology, the water temperature remains consistent, ensuring those luxurious long showers won't get interrupted even if the demand is high. This model provides an impressive 24kW power rating and can heat water to a range of 68° to 140°F, suitable for various uses.

The unit is also eco-friendly, thanks to its auto-modulation feature and electronic water flow control, which help save energy and reduce your utility bills. Additionally, the small and sleek design of this heater allows for easy wall mounting and space-saving installation without the need for venting, making it ideal for homes with limited space. The digital display and user-friendly preset temperature and memory buttons make operation straightforward and convenient.

However, it requires a minimum electric service of 150 amps, which may necessitate an electrical upgrade in some homes. The included warranties (7-year leakage and 3-year parts) provide some peace of mind regarding durability and reliability. While the flow rate won't match that of larger tank heaters, its performance is solid for its size and category. This model will be particularly beneficial in smaller homes or for users looking to save space and energy while still enjoying the convenience of endless hot water.

Rating
9.8
Flow Rate
Temperature Rise
Power Rating

Most important from
2063 reviews

Flow Rate
Ability to provide a continuous flow of hot water even when running two showers simultaneously.
Temperature Rise
Accurate temperature control ensures you get the hot water you desire without any fuss.
Power Rating
Using no power when not in use, and delivers instant hot water upon return.
Size and Installation
Impressively quiet and space-saving design is a game-changer.
#3

Rheem 18kW 240V Tankless Electric Water Heater, Gray

Rating
9.6
Flow Rate
Power Rating
Size and Installation

Most important from
1941 reviews

Flow Rate
It'll get warmer before it gets hot in the shower; you need to let it run longer or adjust while showering.
Power Rating
Pulls about 8kw upon use.
Size and Installation
Installed in a tiny house and works wonderfully.

The Rheem 18kW 240V Tankless Electric Water Heater is a compact and efficient solution for your hot water needs. One of its standout features is the external digital thermostatic control with an LED display, offering precise temperature adjustments within a one-degree accuracy, which allows for more consistent water temperature. The heater uses advanced self-modulation technology to adjust power based on the hot water demand, which can contribute to energy efficiency and potentially lower electricity bills. It has a flow rate of up to 4.4 gallons per minute (GPM), making it suitable for small to medium households, especially those with lower simultaneous hot water needs.

The heater is powered by 18,000 watts, ensuring quick heating capabilities. However, keep in mind that the higher power rating may require adequate electrical infrastructure in your home. The durable copper immersion heating elements are field serviceable, adding to the product's longevity and ease of maintenance. Installation is relatively simple, thanks to the bottom 3/4 inch NPT water connections and threaded design for easy replacement. The compact dimensions (14.5 inches wide by 18.25 inches high) allow it to fit in tight spaces, which is a significant advantage for homes with limited installation areas.

This Rheem model is ideal for those who need a reliable, space-saving water heater with advanced temperature control features, but should verify installation requirements beforehand.

Rating
9.6
Flow Rate
Power Rating
Size and Installation

Most important from
1941 reviews

Flow Rate
It'll get warmer before it gets hot in the shower; you need to let it run longer or adjust while showering.
Power Rating
Pulls about 8kw upon use.
Size and Installation
Installed in a tiny house and works wonderfully.

Buying Guide for the Best Compact Tankless Electric Hot Water Heaters

Choosing the right compact tankless electric hot water heater can significantly improve your home's energy efficiency and ensure you have a reliable supply of hot water. These heaters are designed to provide hot water on demand without the need for a bulky storage tank, making them ideal for smaller spaces. To make an informed decision, it's important to understand the key specifications and how they align with your needs.
Flow RateFlow rate, measured in gallons per minute (GPM), indicates how much hot water the heater can produce at a given time. This is crucial because it determines whether the heater can meet your household's hot water demands. Lower flow rates (1-3 GPM) are suitable for small households or single applications like a shower or sink. Higher flow rates (4-6 GPM) can handle multiple simultaneous uses, such as running a shower and a dishwasher at the same time. Assess your household's hot water usage to choose the right flow rate.
Temperature RiseTemperature rise refers to the increase in water temperature as it passes through the heater. This is important because it affects how hot the water will be when it reaches your tap. A higher temperature rise is needed in colder climates where the incoming water temperature is lower. For example, if you need a 70°F rise to achieve your desired hot water temperature, ensure the heater can provide that at your required flow rate. Consider your local water temperature and desired output temperature to determine the necessary temperature rise.
Power RatingThe power rating, measured in kilowatts (kW), indicates the electrical power the heater uses to heat the water. This is important for understanding the heater's efficiency and compatibility with your home's electrical system. Lower power ratings (3-6 kW) are suitable for smaller applications or lower flow rates, while higher power ratings (7-12 kW) can handle larger demands. Ensure your home's electrical system can support the heater's power requirements and choose a power rating that matches your hot water needs.
Energy EfficiencyEnergy efficiency, often expressed as a percentage, indicates how effectively the heater converts electrical energy into hot water. Higher efficiency means lower energy consumption and reduced utility bills. Look for heaters with efficiency ratings of 90% or higher for the best performance. Consider your long-term energy savings and environmental impact when evaluating efficiency.
Size and InstallationThe physical size of the heater and its installation requirements are important for ensuring it fits in your available space and can be installed properly. Compact models are ideal for small spaces like under sinks or in closets. Check the dimensions and installation guidelines to ensure compatibility with your space. Consider where you plan to install the heater and ensure it meets the necessary clearance and ventilation requirements.
Warranty and SupportA good warranty and reliable customer support are important for peace of mind and long-term satisfaction. Warranties typically cover parts and labor for a certain period, often ranging from 1 to 5 years. Look for heaters with longer warranties and positive customer reviews regarding support. Consider the manufacturer's reputation and the availability of service in your area when making your decision.

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