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Things to consider when installing and purchasing an electric shower

Dimplex Shower

Have you been looking at different options of electric showers? There are several on the market and it can be very overwhelming. We have spoken to our experts to get some tips on things to consider when purchasing an electric shower and installing the shower. At Dimplex we offer two different models of electric showers, Verve and Vital.

What type of shower is best suited for my home?

Most modern homes are fitted with combination boilers, with this type of installation then a mixer shower is what you would have installed. A mixer system takes the hot water from your combination boiler and draws it to one side of your Thermostatic Mixer Valve (TMV), cold water is also taken from your cold-water supply and is also fed to the TMV.

The TMV then blends the 2 together by using the valve/lever mounted on the front of your TMV. The hot and cold are mixed/blended to create a suitable showering water temperature. The only problem with having this system is that if your combination boiler fails, then you do not have any hot water for washing, heating, or bathing/showering.

What water pressure do I require for my electric shower?

There are a few important requirements you also need to know about before installing an electric shower:

  • The water at your mains entry must have a minimum running pressure of 1 bar and ideally your water must flow at a rate of 8 litres per minute.
  • It should also have a maximum static pressure of 10 bar
  • Depending on the location of your house can greatly affect your pressure for example, is your house on top of a hill? How far from the pumping station? How many other properties draw the same water and if they all turn on a cold tap at the same time, what happens to my pressure?
  • Generally, most households are guaranteed to receive a minimum of 1Bar=14.5psi of pressure, showers require a minimum of 1 bar to operate safely if the water pressure drops below 1 bar your electric shower will not work correctly.
  • Electric showers also have an upper working limit of 10bar, anything greater than this can cause problems.
  • Most electric showers will be configured for these water bye-law stipulations, but it is as well to check with the manufacturer’s instructions.

Is a power shower the same as an electric shower?

The main difference lies in how water is fed into your shower. With an electric shower—only cold water is fed into the shower. Some of this water is passed over an electrical heating element and then passed directly to the shower head. With a power shower—both cold and hot water from your boiler tank is fed into your shower, then mixed to reach your set temperature.

Power showers also use an electric pump to increase water pressure. While electric showers rely on the pressure of your mains water supply only—which doesn’t use a pump.

Cable Sizing

The simple answer to ‘what size cable do I need’ is always to consult a qualified domestic electrician, he can offer good advice and ensure your shower is fitted using the correct cable size. Electric showers come in various power options however the most common power options are 7.5kW, 8.5kW, 9kW, and 10.8kW. There is even an 11kW which is a rare option.

Traditionally older houses were all fitted with 6mm electric cable, this limits the size of shower you can fit and as a ‘rule of thumb’ 8kW is the largest rated shower that should be fitted on a 6mm supply.

Most modern homes are fitted with 10mm electric cable and can accommodate the larger. Higher kW showers however care must be taken as fitting a shower that is too high (kW) on smaller cable size can be dangerous and employing the advice of a qualified electrician is always the safest option.

cables under the shower

Will having a higher Kilowatt rated shower improve performance?

Within an electric shower, the cold water is passed over a heating element. The temperature control dial on your shower controls how long cold water is passed over the heating device for—the longer, the hotter.

When you increase the temperature setting, you might sometimes notice a slight dip in pressure as the water flow slows down to increase heat. This is where the kW rating comes in, the higher the kW rating, the faster your shower can heat water to a hotter temperature. This means that the water can maintain a more consistent pressure-resulting in better shower experience.

Cable size does play a key part in the ability to install a higher rated kW shower. It is best to consult a qualified electrician for advice.

I have hard water; will this affect my shower?

If you live in a hard water area, then paying that little bit more for a shower with ‘Phased Shutdown’ or an Anti-Scale feature will be a benefit.

What is phased shutdown or Anti Scale?

Phased Shutdown is the removal of hot water from inside your showers tank when you turn off the shower and replacing it with cold. If you turn of your shower and it continues to run for 3 or 4 seconds, then it has phase shutdown or anti scale. What this feature does is keep the water temperature in your showers heating tank below 50 as this is the temperature that scale crystalizes. If when you stop showering the hot water held within the shower is removed and replaced with cold, then the temperature is lowered, and the scale is minimized.

Another added benefit is when you have someone getting into the shower directly after you, if the water inside the shower is hot and they turn on the shower then the first water to come out of the shower can be at 50 and potentially scald. Having phase shutdown will reduce limescale and stop the risk of a scald upon start up.

Explore our range of electric showers to find the best fit for your home.