a man adjusting a mixer shower

It seems that we Brits love our showers. In fact, research from Victorian Plumbing shows that 57 per cent of people prefer a shower compared with 32 per cent favouring a bath. The remaining 11 per cent couldn’t decide between the two. More and more, we’re seeing bathtubs taken out and replaced with walk-in showers that take up less space and use less water. So with the shower being the clear winner, we thought that it was time to examine the different types of showers available, as well as how much they could cost to run. 

Manual mixer shower

A manual mixer shower is the most standard type of shower in the UK. They take water from both your hot feed (inside your hot water tank) and cold feed (the tank in the loft) and mix them together to reach the temperature you’ve requested.

However, there are three different types of mixer shower: Exposed Valve (EV), Built-In Rigid (BIR) and Built-In Valve (BIV). So what does each of these things mean? Essentially, they simply explain how the mixer is installed and which aspects you can see.

EV mixers have the whole shower control on show and the pipes connect through the wall, as in the image below.

an exposed valve mixer shower with grey tiles

Both BIR and BIV showers hide the pipes, so you simply have a temperature control, as in the image below. They are sometimes known as ‘concealed mixers’.

a BIR mixer shower with marble tiles

Mixer showers can be used both in a walk-in unit as well as over a bathtub. The shower handset is usually attached to the wall via a rail, but can be removed if needed. As already mentioned, mixer showers are the most popular type of shower in the UK, however, they work best if your home already has good water pressure. This is because they rely on mains pressure to operate, so if your home has low water pressure, a mixer shower may not be the one for you.

If you’re concerned about this being an issue, you could turn your mixer shower into a power shower. Essentially, a power shower just has an additional pump that increases the water pressure, but it works in exactly the same way as a mixer.

One of the potential negatives of a mixer shower is its inability to react to fluctuating temperatures. You may find that it frequently goes hot and cold and this is because it can struggle to know exactly how much hot or cold water is needed to reach the requested temperature. This is where thermostatic showers have a slight advantage. 

Thermostatic showers

Just like a mixer shower, a thermostatic shower mixes both the hot and cold water feeds together in order to reach your desired water temperature. However, it differs in that it contains an internal thermostatic valve, which helps the unit to maintain a constant water temperature.  

How do thermostatic showers work?

Thermostatic showers are capable of balancing the water temperature because of four main components: the element, return spring, piston and temperature control.

First, the thermostatic element will expand or contract depending on the temperature of the water that flows through it. This element is attached to a piston, which in turn moves as the element expands. The piston will therefore either reduce the amount of hot water or increase the amount of cold water as needed to create a static temperature that doesn’t fluctuate. The return spring works in the opposite way to the piston. When the element contracts (instead of expands), the spring will move the piston to increase the temperature, either by adding more water or decreasing the cold water.

The temperature control allows you to manipulate the heat, increasing it or decreasing it for your own comfort. When you do this, all of the above components work together to ensure that the shower is delivering the water at the proper temperature.

The thermostatic valve allows the shower to react to changes in temperature and instantly balance the water as needed. The hot and cold water are perfectly mixed together to provide one set temperature, so there’s no blast of scalding water followed by water that’s the same temperature as the Arctic Ocean.

An additional safety feature means that the shower will cut out should the cold water supply fail, so you don’t have to worry about family members, such as young children, being scalded by burning hot water. 

Is a thermostatic shower electric?

Thermostatic showers aren’t electric. They don’t use electricity but instead rely on mains pressure, while the water is heated by your boiler.

How much does it cost to run a thermostatic shower?

A thermostatic or mixer shower that doesn’t have a pump attached will use on average 12 litres of water per minute. Therefore, a 10-minute shower could use up to 120 litres of water. According to This Is Money, you would pay around 23 pence in gas to heat this water, and therefore a 10-minute shower will cost 23 pence when the water has been heated by your gas boiler*. 

Electric showers

Electric showers are the second most popular option after a mixer shower. Generally, people like this option because the hot water is instant and you can’t run out, as it’s generated by the shower and not the boiler. They’re also a good option for households with low water pressure.

You will know if you have an electric shower, as it will have a box on the wall, like the one below.

* https://www.thisismoney.co.uk/money/experts/article-2176415/Is-cheaper-run-electric-power-shower-whats-difference.html 

an electric shower on the wall with white tiles behind it

How does an electric shower work?

Put simply, an electric shower works in much the same way as a kettle does to boil water. The box contains a heated element that warms up the water that passes through it directly from the mains water feed. By the time the water reaches the shower head, it will be the correct temperature as set by you.

There are some things to consider when having an electric shower installed. Your home’s water supply must have a minimum running pressure of one bar and should flow at around eight litres per minute. 

Do electric showers use a lot of electricity?

Electric showers are sized in kilowatts (kW) from 7 kW to 10.5 kW. This is how much electricity they would use if they were left running for one hour. Therefore, in 10 minutes, a 7.5 kW shower would use 1.25 kWh of electricity. As the average daily energy usage of a house is 8 to 10 kWh, an electric shower could use up a fairly decent chunk of this. In comparison, a desktop computer uses around 0.1 kWh per hour and a washing machine uses 1 kWh in a one-hour cycle. So you can see that an electric shower uses much more than this.

Are electric showers more expensive to run?

Electricity currently costs around 12 to 15 pence per kWh. Therefore, based on the calculations above, running a 7.5 kW shower for 10 minutes would cost you around 16 pence. This doesn’t sound like a lot, but if you increase the power to 10.5 kW and the shower time to 15 minutes, it could go up to as much as 33 pence.

Based on our previous calculations, where we estimated that a mixer shower would cost around 23 pence to run for 10 minutes, the difference between a mixer and electric shower isn’t that much. 

Sources:

  • uk.style.yahoo.com/official-british-people-vote-showers-baths-161014721.html
  • bathstore.com/buyers-guides/showers/which-shower-system-should-i-choose
  • plumbworld.co.uk/blog/thermostatic-shower-buying-guide
  • soakology.co.uk/how-to-bathroom/power-shower-vs-electric-shower-everything-you-need-to-know/
  • thisismoney.co.uk/money/experts/article-2176415/Is-cheaper-run-electric-power-shower-whats-difference.html
  • plumbworld.co.uk/blog/benefits-of-mixer-showers
  • victoriaplum.com/blog/posts/how-does-a-thermostatic-shower-valve-work
  • plumbworld.co.uk/blog/electric-shower-buying-guide
  • heatandplumb.com/blog/how-does-an-electric-shower-work 


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