Best tankless water heater 2021

Which is the best tankless water heater in the UK?


The 10 best tankless water heaters to buy in the UK

The top 10 list of the best tankless water heaters lists various brands and prices

Review10Best compares the best tankless water heaters in the UK and selects the one by Zerodis as the best tankless water heater. In a tankless water heater buying guide, you can read more about the features of the different tankless water heaters and see a recommendation on which tankless water heater to buy in the UK in 2021. By considering the top list of tankless water heaters, you can find the best tankless water heaters and save time shopping online.

Table of contents

  1. Read the ultimate tankless water heater buying guide
  2. View the tankless water heater picks and see how they rank in the top list

(skip buying guide)

Best tankless water heaters: A complete buying guide

All you need to know before buying a great tankless water heater

Picture of a tankless water heater

Finding the best tankless water heater system for your home can help save a lot of money in energy bills, although knowing what to look for in a heating system can be challenging for anyone that isn’t a plumber. Given the cost of paying for a new heating system, you will want to put a lot of thought and consideration into your decision, which is not always easy if you are unfamiliar with what a tankless water heater is and how to choose the right one for your home.

To help with this, we have created a handy buying guide that covers all the information that you need to know to find the best tankless water heaters for your home.

What are tankless water heaters?

As the name suggests, a tankless water heater is a type of water heating system that does not use a large water tank to store heated water. Instead, cold water passes through a pipe and into the heating unit, which uses either a gas burner or electric element to instantly heat the water. Whenever you turn on hot water, you instantly get a constant supply as there is no need to wait for a tank to fill with heated water. Therefore, a good tankless water heater makes hot water very convenient and energy-efficient.

Why should you buy a good tankless water heater?

One of the major benefits of using tankless water heaters is reduced energy consumption. Because there is no tank to fill and store with hot water, it can help to reduce water heating bills. Furthermore, while the initial cost of installation is higher than a tanked water heater, the best tankless water heaters are much more durable so will last significantly longer. This means you can save money over the long term, making it a fantastic investment for many homeowners.

Another picture of a tankless water heater
How to choose the right tankless water heater?

Choosing a new tankless water heater can be daunting for those unfamiliar with water heating systems. So here are some things to consider that can make the process easier:

  • Hot Water Consumption: You need to determine how much hot water you consume daily so that you can select a tankless water heater that meets the demand. Simply list all the fixtures in your home that use hot water at any time (e.g. faucet, shower head, dishwasher) and combine their flow rates. To check flow rate, simply refer to the manufacturer instructions for any fixture you’ve bought or check online for a rough estimate of each fixture.
  • Temperature Rise: This refers to the temperature that the heater uses to warm incoming water to the desired temperature. To calculate, you need to determine the average temperature of incoming water and subtract from the desired incoming temperature.
  • Power Source: A tankless water heater is either gas-powered or electric, so consider which is best for your needs. Electric is suitable for smaller water heaters designed for point of use (e.g. heating water for just the shower), while gas-powered water heaters are best for an entire household’s water heating.
What is the best kind of tankless water heater in the UK?

There are two main types of tankless water heaters available to buy:

  • Gas-powered Tankless Water Heaters: Gas-powered systems are more powered and the most used, being the best tankless water heater for an entire household. However, you need to ensure that appropriate piping is in place and consider its location relative to where the heater will go, otherwise extensive installation work may be necessary.
  • Electric Tankless Water Heaters: Electrically powered systems are only recommended for point of use rather than a whole household, as it puts too much strain on the electrical supply when forced to heat too much water. It is more affordable to install, however.
…are you ready for the best picks of 2021?

Top 10 list of tankless water heaters in the UK (July 2021)

The bestseller list compares brands and their tankless water heaters. Which tankless water heater is the best?
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Best choice* TOP 1
Image of Zerodis Zerodis8vqhd57fos tankless water heater
220V 6500W Tankless Instant Electric Hot Water Heater with Shower Head for Home Bathroom Shower*
  • Safe and long lifespan, automatic power-off when water is off and over-temperature…
  • Large LED screen shows temperature clearly, touch button for easy operation
  • Low water pressure to start, users of higher floors can enjoy pleasant experience…
Image of RBAYSALE JSD12-S02-LPG tankless water heater
RBAYSALE Gas Water Heaters 6L 1200W 2800Pa LPG Instant Hot Water Heater Boiler Tankless Portable with Shower Head Pure Copper Water Tank for Bath Indoor Outdoor Glamping RV Caravan Horse*
  • Space saving and quick installation- LPG Water Heater connect the water inlet, water…
  • Multiple protection-Tankless Water Heater with flame failure protection, overheating…
  • Instant and 0.02Mpa Low pressure startup Instant water heaters do not need to wait.Even…
Image of Haofy  tankless water heater
Mini Electric Water Heater, 3000W Tankless Instant Hot Water Heater Boiler with LCD Display, Under Sink Basin, Auto Power Off Shower Hot Water System for Kitchen Bathroom Washing (Black)*
  • Energy conservation saves water waiting for hot water to reach the tap, reduces heat…
  • Constant temperature This electric temperature control device guarantees a constant…
  • Ensure safety Built-in leakage protection device. It turns off automatically due…
Offer* TOP 4
Image of Garosa Garosackwhr4axf61282-02 tankless water heater
3000W Mini Water Heater Mini Electric Tankless Instant Hot Water Heater for Bathroom Kitchen Home Washing(Gold)*
  • Stainless construction with mini design, it is durable, elegant and fashionable.
  • Freely adjust water temperature by water flow, simple operation.
  • LCD digital temperature display, safe heater, electricity saving, water saving, no…
Image of CAMPLUX BW264BC tankless water heater
Camplux BW264BC 10L Instant Gas Water Heater Outdoor, Tankless Portable Water Heater with Rain Cap, On-Demand LPG Boiler for Camping Shower RV Trip Horse Washing, A+*
  • CE CERTIFIED GAR STANDARD - To provide a safer bathing environment, Camplux BW264BC…
  • EASY TO INSTALL & USE - The water heater is equipped with basic installation…
  • WEATHERPROOF RAIN CAP - The stainless steel rain cap design can prevent rain, leaves,…
Image of Eccotemp CE37-L5 tankless water heater
Eccotemp CE-L5 6.0 LPM Portable Outdoor Tankless Water Heater, 37 mbar*
  • Rated at 6 Liters per minute (LPM), the CEL5 can produce hot water with water pressure…
  • Real, appointment based dedicated support available M-F, 8am-8pm EST. Eccotemp also…
  • Runs on a standard 20 lb. liquid propane tank and is equipped with an electronic…
Image of Weiyiroty Weiyirotymfyazxo9bv-02 tankless water heater
Electric Tankless Water Heater, 220V 3000W Mini Tankless Instant Hot Water Heater Bathroom Kitchen Washing with LED Indicator Light, Rust Proof, Corrosion Resistant(White)*
  • Stainless construction with stylish design, it is rust proof, corrosion resistant,…
  • LED indicator light to show you the power and heating status
  • Build-in turbo heating part and the blow off valve for safe heating system
Image of Focket Focketo3evdwx8yt-13 tankless water heater
Focket Electric Water Heater, White Rapid Heating Mini Tankless Instant Hot Water Heater Hot Cold Dual-use Under Sink Water Heater, Electricity Saving and Water Saving for Home Washing (220V 3000W)*
  • WIDELY APPLICATIONS This is a water heater for the application of changing the cold…
  • SAFE USE Safe heater, electricity saving, water saving, no pollution, no exhaust…
Image of CAMPLUX ENJOY OUTDOOR LIFE AY132P43 tankless water heater
Camplux AY132P43 5L Portable Gas Water Heater with 4.3L Water Pump 12V, Tankless LP Gas Boiler with Folding Handle, Use for Outdoor Camping Shower RV Trip Washing Horse*
  • EASY TO OPERATE - You can simply adjust the water and gas flow to achieve your desired…
  • FOLDABLE HANDLE FOR EASY CARRY- This gas shower only weighs 4.54kg, with a handle,…
  • SAVING ENERGY & MONEY- Camplux AY132P43 employs energy saving technology, higher…
TOP 10
Image of RBAYSALE HP-M10374-2 tankless water heater
RBAYSALE Water Heater Gas Portable Liquid Gas Water Heater Tankless Instant Boiler with Copper Water Tank for Home, Shower, Outdoor Camping, Horse Shower (6l)*
  • Multiple protection - Flame failure protection, overheating protection, shutdown…
  • High Quality - Propane Gas Water Heater Brushed Stainless Steel Housing. Waterproof…
  • Wide application - Gas water heater for showering, washing pets, cleaning outdoors,…
Affiliate Disclosure

* We participate in the Amazon Associates Program. As an Amazon Associate we earn from qualifying purchases. For the list of the best tankless water heaters, we consider only products that are available on Amazon while the ranking is based on factors such as customer reviews, number of sales and keyword. It is not a tankless water heater test. Last Update: 2021/07/31.