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New Combi Boiler Installation

Combi boilers and Help-Link

There are different boiler technologies available that could provide heating solutions perfect for you personal needs. In this guide, we’ll explain one of these boilers technologies: combi boilers. Read on to learn what a combi boiler is, how it works, the associated costs and how it compares to other types available.

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Simply answer a few multiple choice questions about your existing boiler and we’ll give you a fixed price for a new boiler including all parts and installation[28]

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What is a combi boiler – and how does it work?

A combi – or combination – boiler is a single, compact unit that functions as both a water heater and a central heating boiler. This space saver heats water immediately, rather than heating and storing, which removes the need for a bulky hot water storage cylinder or cold water storage tank, as found with old boiler systems.

How a combi boiler heats water

To provide hot water, combi boilers are on constant standby and connected to the mains water supply. When a tap is turned on, the boiler is triggered into action and it heats the water through a heat exchanger, for on-demand hot water any time of day.

How a combi boiler provides central heating

A combi boiler follows the same heating process as a conventional boiler, but the expansion tank is contained in the boiler itself, so water is heated within the boiler before being sent to the radiators.

A conventional boiler has a separate expansion tank to heat water – usually in a house’s loft – and is connected to the boiler using an external feed, which takes up quite a lot of space.

Combi Boiler Diagram

How does a combi boiler compare to other types of boilers?

There are two other main types of boilers besides the combi version; system and standard boilers.

Standard Boilers

Standard boilers are the traditional set-up, with a heating system, hot water cylinder and cold water storage tank. These bulkier systems take up significantly more room than a combi boiler, but are ideal for anyone with an older house as the system will already be set up, potentially making for a much easier installation. They’re also ideal for anyone with a large, busy house, or with weak local water pressure, as they should withstand simultaneous use.

Standard Boiler Diagram

System Boilers

System boilers are almost a hybrid between standard and combi boilers. They use a hot water cylinder to store water, but the hot water system is stored within the unit – just like a combi boiler. They’re slightly more powerful than a combi boiler, which is great for busy homes, and compact enough to be fitted within a smaller house as no loft space is needed.

System Boiler Diagram

What are the benefits of a combi boiler?

Space saving is a real perk of this boiler system. Rather than requiring room for large water storage cylinders or tanks, combi boilers are compact, making them ideal for many living in a smaller space such as a flat, or anyone looking to save room in their loft.

As there are fewer pieces to the boiler, you have a much lower risk of your pipes freezing, which can be a major concern in winter. This also means combi boilers are typically quicker and easier to install than standard boilers, as there are fewer parts to fit.

Are there any disadvantages of a combi boiler?

If you have a large, busy household with multiple bathrooms, you could lose water pressure, depending on the mains pressure in your area. You should check the pressure levels in your area before choosing your boiler type.

The nature of the combi boiler means all of the heating takes place within one central unit. Because of this, the unit must prioritise certain actions, meaning when the hot water is turned on, the central heating will be paused. It should, however, automatically switch back when hot water is no longer needed.

How much does a combi boiler cost?

The price of a combi boiler differs depending on the brand, size, output and maximum flow rate. The more powerful the boiler, the more it’s likely to cost. Rather than trying to cut costs, you’ll need to choose your new boiler based on the requirements of your home.

Combi boilers come in various outputs with a 24kW model being suitable for small homes such as flats and very small houses. A 28kW boiler costs slightly more and would suit a medium-sized home such as a semi-detached house.

If you have a large home such as a big detached house, you’ll likely need a boiler with a 35kW to 42kW output, which is more costly.

At Help-Link, we offer three of the most reliable and efficient brands on the UK boiler market: Worcester Bosch Group, Vokèra and Ideal. So, whatever size or price you have to pay, you can be guaranteed an excellent, energy efficient and long-lasting boiler.

How much does it cost to install a combi boiler?

Installation costs might fluctuate depending on the type of work needed. Never be tempted to try and save money by installing one yourself – any new boiler must be installed by a Gas Safe registered engineer.

If price is important to you when buying a new boiler, it’s best to work out which type will be the most cost effective with regards to installation, as well as in the future.

In some cases, switching a like for like boiler (e.g. combi boiler for combi boiler) could be the cheapest option when replacing your system, but not always.

Bottom line: do a little research and ask for quotes on a few options.

Get in touch today and we can provide you with a personalised quote for your boiler installation. Along with a professional, friendly service, you’ll also receive a manufacturer backed warranty, and the opportunity to purchase a Customer Care Package, which includes unlimited callouts, a 24/7 care line, and more.

Want to talk your boiler options through?

A boiler is a big decision. If you want to talk through something in person, simply fill in the form below to give us an idea of where you are and one of our local advisors will give you a call back quick-sharp.

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[28] Exclusions apply. See

[79] 5% online discount is available to domestic gas and LPG customers who receive an online quote for all boiler brands excluding the Ideal Logic HE24, HE30, HO15 & HO18 and Worcester Bosch 25i ERP, 30i ERP, 15ri & 18ri boilers which qualify for the summer bundles offer. £50 additional discount available on all like-for-like system swaps and a £100 discount is available on conventional to combi, and combi to conventional boiler swaps. Online discounted price is only available for the duration of the 14-day quote validity which starts from the day the quote was given. Help-Link UK Ltd include a filter as part of your quote as this is highly recommended by the boiler manufacturer as a key component in maintaining boiler health, functionality and may potentially be looked upon favourably by manufacturers when assessing warranty work. This filter can be removed at the customer’s request. Quote also includes a programmable thermostat for all combi boiler installations as this is a legal requirement as part of the Boiler + legislation introduced 6th April 2018, and cannot be removed from the installation unless; it is replaced with an alternative smart thermostat; or another energy saving measure as listed in the Boiler + legislation or if a smart thermostat already exists within the property. Offer is not available to Help-Link UK Ltd or HomeServe group employees. This offer cannot be used in conjunction with any other offers. Help-Link UK Ltd have the right to withdraw or change the offer at any time. Online discount is automatically applied when the customer gets a quote using the online quote system at and as long as the customer meets all the above criteria.