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The BBW Boiler Installation Guide


All you need to know when it comes to replacing your boiler

Are you looking to replace your existing boiler? Have you had it for a long time? Is it making strange noises and beginning to become unreliable? If the answer to any of these questions is ‘yes’, then it might be time to get a new one. 

But where to start…

Here at Boilers Bathrooms Wetrooms our expert team of boiler installers thought it would be useful to put together a one-stop guide. On this page we’ve included all of the information and answers you’ll need when you’re looking to get a new boiler for your home.

In creating this guide we’ve attempted to condense all of the knowledge we’ve gathered over the last 14 years into something genuinely useful. However, if we’ve missed anything or not answered a question you have, please contact our Bristol showroom and we’ll be happy to help. 

When it comes to navigating through this boiler guide, you can either scroll down the page and read the info as you go, or use the links below to jump directly to the specific sections you’re interested in.

What are the different types of boiler? 

After making the decision to get a new boiler, your next task is to decide which type of boiler will be best for you and your property. 

The three main boiler types are:

Combination boilers
Regular boilers
System boilers

Different fuels are available for each of the above boiler types, with the most common being gas, oil and LPG (short for liquified petroleum gas). 

Over the next three sections we’ll go over each of the boiler types listed above in more detail.

What you need to know about combination (or combi) boilers

A combination boiler, or combi for short, heats water directly from the mains when you turn a hot water tap or the heating on. In recent years combi boilers have become extremely popular with over 70% of UK homes choosing them over other boiler types. 

What are the benefits of getting a combi boiler?

The main benefits of getting a combi boiler installed are detailed below: 

Energy efficiency 

When it comes to energy efficiency, combi boilers have the edge over both regular and system boilers. Switching from an old boiler to a new combi boiler is likely to save you £100’s a year on heating bills. 

Compact boiler design

Because a combi boiler system heats water directly from the mains it doesn’t require a hot water tank. This means your heating system takes up far less room in your property than other boiler types. 

Boiler installation is straightforward

A combi boiler is less complex than either a system or regular boiler. This means it’s relatively quick and easy for a qualified boiler installer to fit your new boiler.

What size combi boiler is best for my property? 

When choosing your new boiler it’s vitally important that you get the right size unit for your property. 

Too small and the boiler system will struggle to heat your property adequately. Too big and you’ll end up wasting energy and spending more on heating bills than you need to. 

We’ve put together the typical house scenarios and included the average number of radiators each property will need and the size of boiler they should go for:

Central heating scenario #1

A property with up to two bedrooms and one bathroom will typically require 10 radiators. In this scenario the recommended output is 24 – 27kW. 

Central heating scenario #2 

A property with up to three bedrooms and two bathroom will typically require 15 radiators. In this scenario the recommended output is 28 – 34kW. 

Central heating scenario #3

A property with over four bedrooms and over three bathrooms will require upwards of 20 radiators. In this scenario the recommended output is 35 – 42kW. 

What you need to know about regular boilers

A regular boiler takes water from a tank and heats it up in a hot water storage cylinder before feeding it into the taps and radiators of the property. 

Regular boilers are the oldest type of boiler system and are referred to as traditional or conventional boilers.

What are the benefits of getting a regular boiler?

The key advantages of having a regular boiler installed at your property are outlined below:

High volumes of water

One of the key advantages of having a regular boiler installed is that it can provide high volumes of water to multiple bathrooms at the same time. This makes it ideal for large families or properties with a high number of occupants. 

Compatible with solar

Despite being the oldest type of boiler available on the market, regular boilers are compatible with solar panel technology. This energy efficient combination not only makes your home heating system more environmentally friendly by reducing carbon emissions, it also helps reduce your heating costs. 

Not impacted by low water pressure

Unlike a combi boiler, which takes water directly from the mains, a regular boiler system has its own water tank built in. This means it is unaffected by low pressure in the mains system. 

Is a regular boiler right for my property?

As already covered in the section above, there are many benefits of choosing a regular boiler system. That being said, they are typically best suited for a larger home as they require space for both a water storage tank and a hot water cylinder.

What you need to know about system boilers

A system boiler is similar to a regular boiler in that it needs a cylinder to store hot water, but unlike a regular boiler it takes its water supply directly from the mains. 

Hot water storage cylinder aside, the majority of the components used in a system boiler to generate heat for your home are built into the unit.

What are the main benefits of having a system boiler?

It can be argued that with a system boiler you’re getting the best bits of both a combi boiler and a regular boiler. The key benefits of choosing a system boiler are detailed below:

Great if you have high water demands

A large water tank is a key part of a system boiler. While this can take up a significant amount of space in your property (meaning it’s not ideal for everybody), those with the space will benefit from being able to run multiple taps at the same time. This can make them the perfect choice for large and/or busy households. 

Straightforward installation

As touched on in our intro above, with a system boiler the majority of the parts and components are included within the boiler unit itself. This can mean it’s more straightforward and, more often than not, neater to install a system boiler than other boiler types. 

Fast and efficient

After the cold water enters the system boiler from the mains, a pump is used to move it to the hot water cylinder. It’s then stored there until required. This fast and efficient process guarantees a supply of hot water can be maintained even with multiple taps or showers running. 

Is a system boiler right for me?

If you and your family need lots of hot water and heat at the same time, then a system boiler might be the best option for you. 

How energy efficient is my boiler?

One of the main reasons you may decide to get a new boiler installed is improved energy efficiency. Not only is a more efficient boiler better for the environment, it will also cost you less money to run.

Checking the efficiency of your existing boiler is fairly straightforward, but the process varies depending on the age of your boiler. 

Newer boilers should have a small sticker somewhere on the front panel with the EU flag in the top left corner. Below this you’ll see a vertical row of coloured lines. These should go from green at the top, through yellow, orange and then red. 

The rating of your boiler will be shown as a black arrow on the right with a letter in it. Ratings go from A++, the best, all the way down to G, the worst. 

For older boilers without the sticker you’ll need the make of the boiler, which should be on the front of the unit itself, and the model name. This second part can be a little more difficult to find, but you should be able to see it somewhere near the controls when you lift the front panel. 

With the make and model you’ll then need to head to the Building Energy Performance Assessment website to find the energy efficiency rating of your boiler. 

Now that you have the rating of your existing boiler you’ll have something to compare with the new units you’re looking at. 

Which boiler brand is best?

While there are lots of boiler brands out there to choose from, here at Boilers Bathrooms Wetrooms we often work with one of the four brands listed below:

Ideal
Vaillant
Worcester Bosch
Glow-worm

Why? Over the years we’ve found the above boiler brands to be some of the most reliable and efficient on the market. However, if you specifically want to go with another manufacturer, we’ll do everything we can to accommodate your request.

Ideal boilers 

Ideal is a well established and trusted boiler brand that has been serving both the domestic and commercial markets since 1906. The company prides itself on their innovation and central heating expertise.

You can find out more about Ideal and explore their full range of boilers by heading to their website

Vaillant boilers 

Vaillant boilers have been in existence for over 140 years and the company was responsible for pioneering the ‘combi’ boiler 35 years ago. The firm is known for producing high quality units and in recent years, it’s investment in renewable technologies.

For more information on Vaillant and what they offer, please visit their website

Worcester Bosch boilers 

Worcester Bosch, commonly known as Worcester, was founded in 1962. The company employs over 2,000 people across sites in Worcester and Clay Cross. The company has an excellent reputation for providing high quality products with excellent aftercare and warranties. 

Head to the Worcester Bosch website to see the full list of products the company offers and learn more about their commitment to customer service.

Glow-worm boilers 

Glow-worm is another leading UK boiler manufacturer. The business has been in existence for over 75 years and invests in hot water cylinders, domestic controls and renewable energy. 

To find out more about Glow-worm boilers and see the full range of products the company offers you can visit their website

Our relationships

We have excellent relationships with the above four boiler brands, meaning we can get the boiler you want for a great price and in quick time. 

You can also be sure that when it comes time to service your boiler, our expert installers have the make and model specific knowledge required to ensure your new boiler is perfect for you and your property. 

Boiler servicing 

Once you’ve had your new boiler installed you’ll want to ensure it remains in tip top condition for as long as possible. Most manufacturers advise that you service your boiler once a year to keep, and in fact some make it a condition of their warranty.

Here at Boilers Bathrooms Wetrooms our team of specialists don’t only handle new boiler installs, we can also take care of your boiler servicing requirements too. What’s more, if you aren’t quite ready to have a new boiler installed and need your old unit repaired – we can help with this too. 

Boiler experts working across Bristol 

Our team of boiler experts have over 50 years’ of combined experience and work across Bristol, Bath and the wider South West. 

Our showroom is located on Wells Road in South Bristol, but our Gas Safe engineers and installers work right across the city. From Bedminster, Whitchurch and Knowle in the South to Clifton, St Pauls, Redland and right at the top of Gloucester road. 

Speak to our team today

If you have any boiler related questions, would like to book an initial consultation or find out more about any of the boiler brands we work with, please get in touch with our showroom today and we will be happy to answer any questions you have. 

You can call us on 0800 002 9541, email boilersbathroomswetrooms@gmail.com or visit our showroom which is located at the crossroads of Wells Road and Airport road, postcode BS14 9AG.

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Working with Customers across Bristol


Our experienced team of plumbers and heating engineers work for domestic and commercial customers in the following areas across Bristol:

Working in the South West


We also work with clients based in smaller towns and villages across the South West, including:

Get in touch with our Bristol team 


Working in Bristol and across the South West

450 Wells Road, Bristol, BS14 9AF

Our team offer a range of boiler, plumbing and bathroom services to clients across Bristol and the South West.

These include new boiler installations, repairs and servicing. Our central heating engineers can install a replacement boiler unit for you. We also offer a full range of bathroom and wetroom services. 

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