Eco Happy (Solar Expert)

Published February 23, 2024

Do you enjoy a deep massaging warm shower over a miserly thin drizzle? Choosing the right shower for your combi boiler can guarantee the former. If you get it wrong, you may spend shower time jogging about under a sorry trickle, desperately seeking a splash of hot water.

There is a fair deal that goes into selecting the best shower options for combi boilers. So let’s get into it!

In this article, we will focus on the three best showers to run alongside combi boilers (spoiler: power showers are not one of them). We will also discuss key factors to consider, such as flow rate, water pressure, usage patterns, as well as specific scenarios, including multiple shower homes and sad water pressure.

The Top 3 Shower Types For Combi Boilers

The three main showers that perform well with combination boilers are thermostatic mixer showers, digital showers and electric showers.

1. Thermostatic mixer showers

A thermostatic mixer shower blends hot and cold water from separate pipes to give you the temperature you’re after. A good combination boiler and a thermostatic mixer shower can be a match made in bathroom heaven.

The mixer’s thermostatic valve ensures that your water maintains a consistent temperature regardless of outside factors like changes in water pressure.

We’ve all been there… You’re showering, when other people in the house decide to do the dishes or run the hose and suddenly your shower is freezing or scalding! The thermostatic valve keeps the temperature consistent, avoiding those two nasty shower surprises.

Some mixer showers have specific anti-scalding technology as an extra safety measure – very beneficial in homes with children or the elderly.

As an industry expert says: “If the hot water flow rate of your boiler is enough to meet the requirements of the mixer then I cannot think of a reason not to use a mixer.” 

In this regard, to align your combi flow rate to your mixer’s performance, you typically need to consider a minimum rate of around 12-15 litres per minute.

Pro: Great for a consistent, safe hot water temperature, even when other home occupants use water while you’re showering.

Con: If the water mains pressure connected to your home is low, this can throttle the shower’s performance and temperature.

2. Digital shower

Digital showers for high-pressure water systems: Digital showers are designed with advanced technology and are intended to align smartly with high-water pressure systems like combi boilers as well as with variable water demands.

The beauty of a digital shower is that it serves individual preferences. Each user can happily preset their preferred temperature and spray pattern. These can often be activated via voice command.

Consider the bouquet of smart tech features a top digital shower offers:

  • Voice control
  • Customised spray
  • Customised temperature
  • Bluetooth connectivity
  • Audio streaming
  • Water-saving settings
  • Stylish LED screen

A customer, Julie, told of returning home after an exhausting European business trip. She said the first thing she did after dumping her bags was activate the preset “relaxation” mode of her digital shower with a simple touch. The shower instantly delivered the precise temperature and flow she desired. The soothing spa-like experience she enjoyed was the perfect de-stresser after her manic week.

Pros: Great for modern bells and whistles and customising preferences for individual users; convenient too.

Cons: Higher upfront cost and possible temperamental behaviour.

3. Electric showers

An electric shower might the the top solution for you due to its versatility and energy efficiency.

Electric showers source water directly from the mains. They have a heating element that warms the water as it passes through the unit. These showers work independently from the boiler or central heating system.

Why is that a benefit?

  • An electric shower is not impacted by other users opening taps elsewhere in the house. As a standalone system, it provides a reliable flow of hot water during your shower.
  • Thanks to heating only the water needed for the shower, it’s pretty energy efficient too.

A good electric shower offers adjustment controls for temperature and flow rate. This gives you further independence from your boiler, allowing you to set your shower preferences and possibly achieve further efficiencies.

The downsides of electric showers include:

  • Temperature fluctuations may be an issue if your water pressure varies.
  • The heating element of an electric shower will wear out over time, especially if it’s a cheap unit. Additional maintenance, element checks, and replacement may be necessary.

Pros: Great for providing hot water showers independently from your combination boiler. This allows you to set the temperature and flow in the shower and possibly make energy savings.

Cons: If the electric shower goes on the fritz and your shower valve isn’t compatible with your combi boiler, you might be without hot water in the shower.

Choosing The Right Shower For Your Combi Boiler

We all want a shower that looks stylish and inviting. But, as much as looks, design, and budget are important, there are a few other factors to consider when selecting a shower for a new combi boiler.

  • Shower temperature and shower length: A boiler must work hard to bring you those long hot showers. If that’s your (guilty) pleasure, choose a shower that matches the combi’s performance.
  • Water and combi boiler usage preferences: If several people are likely to use water simultaneously (e.g. showering while the dishwasher is running), both the combi boiler and the shower must be able to deliver without sacrificing temperature and strength.
  • Budget considerations: Remember to factor in the unit cost, installation cost, and likely ongoing maintenance of the shower when doing your number crunching.

Selecting the right shower for your combi boiler will set you up for years of blissful, hassle-free showering in piping hot water!

Understanding Shower Flow Rate

Whether you shower under a mighty Niagra Falls or a poor drizzle, understanding the flow rate is important. Flow rate is the volume of water in litres your showerhead streams per minute.

Acceptable flow rates for your combi boiler

Once your combination boiler is fired up, how much water can it drive through the system to your taps and showers? For a decent shower, you want at least 12-15 litres a minute. A good boiler will help ensure the taps throughout your home get hot water at a healthy flow.

There is a limitation, however. Your combi boiler relies on the flow rate from your mains supply. If your mains pressure is weak, even a powerful boiler is unable to perform at full capacity. It’s similar to an expensive new football striker failing to score goals because his teammates aren’t good enough to get him the ball.

Balancing your flow rate

Managing your flow rate effectively helps provide an enjoyable, stable shower flow with a consistent water temperature. Water-efficient showerheads and shorter showers will support overall efficiency in a combi boiler system.

When picking showers for combi boilers, it’s always a good idea to have a professional check over the property’s plumbing setup to assess what will work and what won’t. You always want to make sure that the shower valve (the plumbing device that controls the flow and temperature of water) is compatible with a combi boiler.

Why Not Power Showers?

A power shower provides a powerful cascade of water thanks to an in-built pump that intensifies pressure and spray. This shower system is usually associated with conventional boilers because it draws its water supply from a conventional hot water storage cylinder.

Shower flow rates and power showers

The power flow is generated by an integrated pump that increases the water pressure from a hot water cylinder. This can be a great boost in lower-pressure areas, improving the shower experience.

Because a combination boiler is designed for a higher-pressure environment and takes water from the mains (rather than a hot water cylinder), power showers and combi boilers are not compatible. As much as you may love a power shower, it sadly isn’t an option with a combi boiler.

While power showers are popular and pleasurable, their increased pressure may place a dangerous strain on your plumbing system, causing pipe and unit damage. Water wastage and a higher risk of scalding are other concerns.

Considerations For Specific Needs

The question of the best shower for a combi boiler can become slightly more complicated in households with multiple showers and homes with weak pressure.

Family homes with multiple showers

For homes with two or more showers, more factors come into play. Running three showers at the same time from a combi boiler will result in fairly miserable showers. Even two may be a battle.

You’ll first need to check that you have enough incoming water to feed two showers simultaneously. Then, you’ll want a fairly hefty combi boiler. A 35 kW boiler and 15 litres of flow are probably the minimum requirements to support two showers running together.

An alternate is to have one boiler-connected shower and make your second an electric shower. This should give you two lovely warm showers since they are heated from separate sources.

Homes with weak water pressure

For homes with weak water pressure, a powerful combi boiler can only boost your water pressure so far. A 40 kW combi boiler is usually a pretty powerful appliance but it will be stripped of its power if your mains pressure is too feeble.

With a conventional boiler, you can install a boiler pump to increase water pressure. Unfortunately, this is not possible with your combi boiler since it’s connected to the mains.

Obviously, ensuring that no other taps are running during shower time delivers the best pressure. It’s also advisable to have a plumber check for leaks and damaged pipes because these can also negatively affect pressure.

If you haven’t cleaned your showerhead in a while, doing so may result in miraculously improved shower power!


What happens if my boiler isn’t powerful enough to handle the incoming water pressure to my property?

If your water pressure is bringing water to the shower too fast, the boiler system struggles to heat the water and the shower is often too cold.

What is the best shower head for a combi boiler?

Many showerheads, including rainfall and waterfall heads, go well with combi boilers. A showerhead that can manage variable water pressure is a good idea, as are low-flow showerheads that save water without affecting performance.

What types of showers give you the best water pressure with a combi boiler?

If you have a high-pressure water supply, a mixer shower usually works well. If your mains pressure is low, an electric shower might be more advisable.


Most discussions on the best showers for combi boilers include thermostatic mixers, smart digital showers, and electric showers. The right option for you and your boiler will depend on your preferences, configurations, hot water requirements, pressure, and budget.

It’s best not to rush the decision. Speak to professionals to better understand the compatibility between different systems. Eco Happy wants our clients to be happy with their choices for years to come. Reach out today for expert advice or quotes to help you make the best-informed decision about your next shower and combi boiler.

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