10 Best Tankless Water Heaters 2025 in the UK

The Stiebel Eltron DCE-X Premium Compact Instant Water Heater is a notable option for those seeking a compact and efficient tankless water heater, ideal for shower use. This model stands out with its emphasis on energy efficiency, thanks to its 4i technology and fully electronic closed-loop control, which ensures accurate temperature delivery and maximum energy efficiency. The inclusion of an ECO mode further enhances its energy-saving credentials, making it particularly attractive for users conscious of their energy consumption.

The unit's design is sleek and modern, with a large, backlit multifunction display that simplifies operation, making it user-friendly even for those not familiar with advanced electronics. The size and weight of the heater are within a reasonable range, with dimensions that suggest it should fit easily into smaller spaces, although installation might require professional assistance due to its electrical requirements.

Some potential drawbacks include the specific voltage requirements of 220-240V, which may limit its use in certain regions without the appropriate electrical infrastructure. The 10/12 kW power specification suggests a moderate flow rate, which should be considered for households with higher hot water demands or multiple simultaneous users. While it ranks decently in its category and has positive customer reviews, prospective buyers should consider the specifics of their water heating needs, particularly in terms of flow rate and installation capabilities, to ensure this model meets their requirements. It's a strong contender for those needing a reliable and efficient water heater for personal or small-scale use.

The Thermomate AZ132 5L Portable Gas Water Heater is a compact and lightweight solution for outdoor needs, such as camping showers and RV trips. With a flow rate of 5 liters per minute, it's designed to provide instant hot water with a temperature rise of 25°C, even in areas with low water pressure. This makes it particularly useful for outdoor settings where water pressure might be an issue. The energy efficiency is enhanced by its 3-row burner design, promising to save around 11.5% on gas consumption.

Fuelled by propane, this unit is eco-friendly with an energy class A rating, meaning it efficiently uses fuel to produce hot water. Its portability is a highlight, with a folding handle that makes it easy to carry and install almost anywhere outdoors. The installation process is simple and quick, requiring only basic tools and wall mounting. However, it's important to note that the heater is powered by 2 D batteries, which are not included, and it's designed strictly for outdoor use.

In terms of safety, the Thermomate AZ132 includes essential features like an oxygen depletion shutoff mechanism and protection against overheating and flameout. This ensures that the unit will automatically shut off under certain conditions, providing peace of mind while in use. However, it does require regular maintenance, such as draining residual water to prevent freezing damage. Despite its effectiveness and safety features, the heater's maximum pressure of 7.5 bars may not suit all needs, particularly if higher pressure is required. For those seeking a portable, efficient, and easy-to-use water heating solution for outdoor adventures, the Thermomate AZ132 offers a reliable choice.

This GEESEN 9KW electric tankless water heater offers endless hot water on demand, making it an excellent choice for those wanting continuous showers without waiting for a tank to refill. It delivers a flow rate of about 11 liters per minute, which should suffice for a single shower or sink but might be limited for multiple simultaneous uses in a whole home setting. The built-in smart chip adjusts energy use based on water temperature and flow, helping to save energy and maintain a steady water temperature between 86°F and 131°F, which you can easily control with a digital display.

Since it heats water only when needed, it can reduce heating costs by up to 60% compared to traditional tank heaters and saves space with its compact wall-mounted design. Installation requires a dedicated 240V, 50AMP breaker and appropriate wiring, so it may need professional setup if your home isn’t already equipped for it. The heater includes multiple safety features like overheat protection and IPX4 water resistance, which help prolong its lifespan.

With a 9KW power rating, it is better suited for smaller households or single-point use rather than large homes with high simultaneous water demands. The pink color and included mounting accessories make it a distinctive and convenient option if you want a portable, efficient electric tankless heater. This unit is well-suited for users looking for space-saving, energy-efficient instant hot water primarily for showers or limited use, but it might not meet needs where high flow rates for multiple outlets at once are required.