Oversink Water Heaters

7 products

  • Ariston over sink water heater

    Ariston Andris Lux Electric Oversink Storage Water Heater

    Ariston Andris Lux Electric Oversink Storage Water Heater

    From £115.43 GBP
    From £115.43 GBP
  • Ariston Andris Lux Electric Under sink Storage Water Heater

    Ariston Andris Lux Electric Undersink Storage Water Heater

    Ariston Andris Lux Electric Undersink Storage Water Heater

    From £115.43 GBP
    From £115.43 GBP
  • Ariston Lux under sink water heater 15 litres

    Ariston Andris Lux Electric Undersink Storage Water Heater 6Litre

    Ariston Andris Lux Electric Undersink Storage Water Heater 6Litre

    £111.16 GBP
    £111.16 GBP
  • Dexpro Delux Over Sink Vented Water Heater

    Dexpro Delux Over Sink Vented Water Heater

    Dexpro Delux Over Sink Vented Water Heater

    £67.15 GBP
    £94.80 GBP -30%
    £67.15 GBP
    £94.80 GBP
  • Dexpro Delux Under Sink Vented Water Heater

    Dexpro Delux Under Sink Vented Water Heater

    Dexpro Delux Under Sink Vented Water Heater

    £95.00 GBP
    £95.00 GBP
  • Zip Aquapoint Unvented Water Heater

    Zip Aquapoint Unvented Oversink/Undersink Water Heater

    Zip Aquapoint Unvented Oversink/Undersink Water Heater

    From £209.62 GBP
    £359.35 GBP -42%
    From £209.62 GBP
    £359.35 GBP
  • Zip Varipoint Oversink Water Heater

    Zip Varipoint Oversink/Undersink Water Heater

    Zip Varipoint Oversink/Undersink Water Heater

    From £432.82 GBP
    £741.98 GBP -42%
    From £432.82 GBP
    £741.98 GBP

Over sink water heaters are a type of point-of-use electric water heater designed to be mounted directly on the wall above or next to a sink or washbasin. Their key advantage is their compact size and convenient placement, which provides quick access to hot water without the need for a central heating system or long pipe runs. This makes them an ideal solution for small kitchens, offices, utility rooms, workshops, or any location where a standalone handwashing station is needed.

The categories of over sink water heaters are primarily defined by their heating method and their pressure system.

1. Storage Over Sink Water Heaters

These heaters have a small, insulated tank that stores and heats a specific volume of water, keeping it ready for immediate use.

  • Capacities: Typically range from 5 to 30 litres (1.3 to 8 gallons), designed for low to medium demand.
  • How they work: Cold water enters the tank and is heated by an electric element controlled by a thermostat. The water is maintained at a set temperature, so it's instantly available when the tap is opened. The tank then refills with cold water, and the heating cycle begins again.
  • Key Features:
    • Ready Supply: Provides a small reservoir of hot water for tasks like washing dishes or hands.
    • Thermostatic Control: Allows for precise temperature setting and prevents overheating.
    • Installation: Their compact, wall-mounted design saves valuable under-sink cabinet space.
  • Limitations: The supply of hot water is limited by the tank's capacity. They have a small amount of standby heat loss.

2. Instantaneous (Tankless) Over Sink Water Heaters

These heaters do not have a storage tank. They heat water on demand as it flows through the unit.

  • How they work: When the tap is turned on, a sensor detects the water flow and activates a powerful electric element, heating the water as it passes through the unit. The heater turns off as soon as the tap is closed.
  • Key Features:
    • Energy Efficiency: They only use electricity when hot water is being drawn, eliminating standby heat loss and saving energy.
    • Unlimited Hot Water: They can provide a continuous supply of hot water, as they don't have a tank that can run out.
    • Small Footprint: Their extremely compact size is ideal for the tightest spaces.
  • Limitations: The flow rate is limited, and the unit's power output must be sufficient for the desired water temperature, especially in colder climates.

3. Vented vs. Unvented Systems

This distinction is crucial for installation and performance and applies to both storage and instantaneous models:

  • Vented (Low Pressure): These heaters are open to atmospheric pressure and require a special vented tap. The tap is part of the system's safety mechanism, allowing for the safe expansion of water as it heats. They are simpler and often more affordable.
  • Unvented (Mains Pressure): These heaters are sealed and connected directly to the mains water supply, delivering water at high pressure. They require an expansion vessel and other safety devices to manage the pressure and are compatible with standard taps. This provides a more powerful flow but has a slightly more complex installation process.

FAQs

  • Is an over sink water heater suitable for a full kitchen sink?

    It depends on your usage. For a kitchen sink where you primarily wash hands and occasionally fill a kettle, a storage model of around 15 litres or a powerful instantaneous model can be sufficient. However, for a high-demand use like washing a large amount of dishes, the limited capacity of a storage model will likely run out quickly, and an instantaneous model may not provide the required flow rate at a high enough temperature. For heavier use, a larger under sink or whole-house heater is often a better choice.

  • What is the difference between a "vented" and an "unvented" over sink heater?

    This distinction relates to how the heater is connected to the plumbing and manages pressure.

    • Vented
      (Low Pressure):       This is a simple, low-pressure system. It uses a special vented tap that allows water to expand as it heats up, preventing pressure from building inside the unit. You must use the tap that comes with the heater.
    • Unvented
      (Mains Pressure):       This is a sealed unit connected directly to the mains water supply, so it delivers water at mains pressure. It requires additional safety devices, such as an expansion vessel, to handle the pressure. It is compatible with standard taps.
  • Do I need a professional to install an over sink water heater?

    Yes, it is highly recommended. While the physical mounting may seem simple, the electrical and plumbing connections require expertise. Improper wiring can be a significant safety hazard, and incorrect plumbing for a vented vs. unvented system can lead to leaks or even a unit failure. A qualified electrician and/or plumber will ensure the installation is safe and complies with all local building codes.

  • Why is the water from my instantaneous over sink heater not hot enough?

    This is a very common issue and is almost always due to the water flowing too quickly through the unit. An instantaneous heater needs a specific amount of time for the water to pass over the heating element to reach the set temperature. To get hotter water, you must reduce the flow at the tap. In some cases, especially in colder climates, the heater's power output may simply not be high enough to heat the incoming cold water to the desired temperature at the flow rate you require.

  • How much space do I need for an over sink water heater?

    One of the main benefits of these heaters is their compact design. The amount of space needed varies by model and capacity, but they are generally designed to fit in a small, out-of-the-way location. A typical 15-liter storage model might be around 40-50 cm high, 30 cm wide, and 25 cm deep. Manufacturers will provide detailed dimensions for each model to ensure it fits the desired installation location.