By Kerry Hale

kW Ratings Explained

  • Wednesday 28 February 2018
  • 5 minute read

There are a lot of things to think about when buying a new electric shower. But before you start choosing styles, colours, panels and heads, you need to get clued up on the most important bit - the kW rating. Words that are usually reserved for electrician's manuals will probably pop-up in the product descriptions but don't worry if you don't fully understand them. With our simple guide, we'll decode the kW shower ratings so you can confidently choose the best fit for you and your home.

What does it mean?

When you look at a list of electric showers you'll find each one categorised by a kW rating. This stands for kilo-watt, which translates to the power and the pressure of the water.

Back to basics

Electric showers work by feeding cold water through their system and heating it up before it flows through the shower head. To reach higher temperatures, the electric shower needs more time to heat it up and, by doing so, releases water at a slower rate and a gentler flow. To resolve this issue and maintain a consistent high-pressure at higher temperatures, higher kilowatt systems were introduced.

In turn, this means the more powerful the shower, the greater the flow of water at your desired temperature. Simply put, if you want hotter water at a higher pressure, you'll need a higher power, and a higher kW rating.

The choices

7.5kW and 8.5kW electric showers

If your household hosts a smaller water tank or an unreliable water supply, this range of kW rates will probably suit you best. 7.5kW and 8.5kW shower rates require less power so the gentler flow of water will mean your shower is unlikely to ever run cold. What's more, they're usually cheaper models to purchase and run. If you're okay with a gentler flow of water as the temperature rises, you can stick with this model.

From 9.0kW up to 10.8kW electric showers

Most people associate a higher kW rate with a better shower. The higher power means a consistently greater flow of water at your selected temperature which can give a real luxury experience. Plus, if you have long, thick hair that often needs a greater water flow to get all of the shampoo and conditioner out easily, this kW rate range is probably your best bet.

Check the power

The devil is in the (technical) details when it comes to choosing the best kW rating for you. Don't immediately opt for a higher kW rating - such as a 10.8kW electric shower that promises the best shower experience - when you aren't sure if your household system can host it. To ensure there's no power outage, you must check that your fuse has the required amount of amps. The general rule is that the higher your kW rating, the more amps required to run it. This also goes for the supporting cable, which may also need to be changed to suit your chosen shower. For more detailed advice, read our guide to Electric Showers and don't forget that you'll always need a professional electrician to install an electric shower.

Check the scales

The final consideration to think about is limescale. Just like a kettle, water in an electric shower is heated by passing over an element that is prone to building up layers of chalky limescale. Over time, this build-up can cause electric showers to breakdown completely, limiting their lifetime. Mira electric showers include a unique technology called Mira Clearscale that reduces the build-up of limescale by up to 50% - which means a shower that lasts longer and performs better, making sure you're getting the best shower every morning without worrying that you're losing power or ruining the heating element.

Besides Mira Clearscale, there are other important benefits to think about choosing a Mira electric shower if you're keen to get the best flow for your money. Our Mira Airboost™ technology adds air induction to the system, increasing the flow by up to 30% without actually using any more water. If you want a powerful shower without counting your kilowatts, flow boosting features like Mira Airboost technology which is part of the Mira Sport Max are an obvious choice - pushing hotter water out of the shower head at a consistently greater force.

Whatever electric shower you go for, it's important to do your research first and make sure you're getting the best system for you and your home.

If you are thinking about replacing your current shower, try our shower replacement tool. Simply enter the name of your current shower and we can help you make your choice.

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