Best Instant Water Heater Buying Guide
Super-convenient and easy to use, there are numerous benefits to owning an electric water heater, whether that’s in your home, motorhome or office:
- They are energy-efficient – if you are looking to manage your energy bills, then look for the EF (energy factor) rating when buying an electric water heater. The higher its EF rating, the more energy efficient it is.
- You get instant hot water – as the unit heats the water internally – via a heating element or fuel source – you get hot water when you need it. And it means that you are not drawing from the hot water storage system you have for heating your home.
- Small and compact – their size and compact design mean they are a versatile water heater that can fit in smaller spaces, so a good choice for water heating on boats, RVs and caravans too.
- They’re environmentally friendly – by heating the amount of water you need, when you need it, instant water heaters are kinder on the environment as they use less energy and water.
- Long Life Expectancy – electric water heaters are pretty robust and built to last, with an average life expectancy of between 10 and 15 years.
To ensure you get the right instant water heater for your needs as well as intended location and space, you need to check for the following:
Capacity – if it has a tank, the size is important as you want to ensure you have an adequate supply of hot water, ‘on tap’.
Energy rating – its energy factor (EF) – the amount of hot water produced per energy consumed over a typical day – is important as it indicates how efficient (and cost-effective) it is. The higher the EF, the more efficient the heater will be.
First hour rating – this is another indication as to the heater’s suitability for your needs. The FHR indicates how many gallons of hot water the heater can supply per hour and so meet your hot water requirements.
Size – you need to ensure the size of the unit as a whole can be installed in the space you are looking to locate it.
Over or under-sink design – these are the two main designs of instant water heater. The over sink design is readily accessible whereas an under-sink style is more discreet and can easily connect with sinks that have storage space underneath.
Under sink is generally more discreet, great for residential settings and connecting to pre-built sinks with available storage space underneath. They can provide a welcome boost to the weak central boiler's supply. Over sink is easily accessible and often features temperature controls.
Safety Features – check the safety features that are available on the hot water heater for extra peace of mind. Look for functions such as water alarms and timers as well as extra features including heater stands and heater blankets.
Anti-scale – limescale build-up can clog and potentially cause damage to the heating element and internal workings of your instant water heater, especially if you live in a hard water area. Some heaters include features that can swirl the water at the bottom of the tank and so help to reduce limescale build-up. Choosing a model that has a long warranty (most warranties are for between 3-12 years) means the element will also be made from thicker material and so more durable and resistant to scaling.
There are two main styles of instant water heater you can choose from – tank and tankless. Both have their pros and cons, with each working best in different situations, so knowing your requirements will help you choose the right type:
Tankless water heaters – more readily recognised as an ‘instant water heater’, tankless water heaters don’t store water but use your mains cold water supply to heat up water as and when needed. They are more compact as well as efficient, by saving the need to keep water heated all the time.
Tankless water heaters also need less space, can be portable (some models are designed specifically for caravan-living or travelling) and only need a basic plumbing set up to work.
Tank water heaters – as the name implies, these heaters have their own water storage tank, which can have large capacity if required. This means you will need to have more space for installing a tank water heater. Tank heaters are not as efficient as tankless, but they are in general cheaper to buy and need little maintenance over the long-term.
Easy to install under the sink, the ATC Water Heater is a versatile mini tank instant water heater that gives 5 litres of hot water at a time. And as it can be either floor or wall mounted, the ATC can be used in a caravan as well as your home. The ATC has a 2kw heat exchanger for instant hot water on demand, with an adjustable thermostat for temperature fine-tuning. Durable, with anti-corrosion protection, when it comes to hot water on the go, the ATC is our review's instantaneous water heater top choice.