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New Back Boiler? Replace It With A Combi

If you have a back boiler installed in your home, there are a variety of reasons to consider updating your system to a modern combi boiler. Despite fewer parts and a longer lifespan, back boilers can be incredibly costly and are generally a lot less energy efficient than modern boilers, which is why most engineers will usually recommend a back boiler replacement with a combi boiler.

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Price Guarantee[28]

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]

Exclusive online discount!

What is a back boiler?

A back boiler is a unit that fits behind a fireplace or a gas fire and produces hot water for central heating and domestic use throughout the home. The back boiler is an outdated system that gained popularity for its reliability in the 60's and 70's, but is now no longer manufactured and are almost never advised for a new installation. The boiler also needs a separate water tank or hot water cylinder to function, which needs to be stored elsewhere in the home.

What is a combi boiler?

A combi (combination) boiler combines the functions of a water heater and a central heating boiler into one, single unit. A combi boiler heats water on demand, therefore eliminates the need for a separate tank or the need to wait for a cylinder to refill. Their compact design means they can usually be conveniently mounted on a wall in the kitchen or utility room. Because of their compact design and excellent energy efficiency rating, they are used in the majority of new boiler installations in the UK.

Why replace a back boiler with a combi boiler?

  1. All new combi boilers are condensing which means that they have a Flue Gas Heat Recovery System, that most back boilers do not have, that recycles the heat from waste gases to preheat the new, cold water as it enters the boiler from the mains.
  2. Combi boilers must achieve an A-rating for energy efficiency. Back boilers typically achieve only 76% energy efficiency compared to 90% achieved by modern combi boilers. Not only could this inefficiency of a back boiler be damaging to the environment, it could also be bad for your wallet too with all that wasted energy racking up an incredibly costly, inconvenient bill. By replacing your back boiler with a combi boiler, you could be making savings of up to £320 a year[41].
  3. In some circumstances, a back boiler could be a hazard in your household because if heated, your back boiler could explode due to the pressure build-up.
  4. Ease of installation because of no need for multiple elements, a Combi boiler can usually be fitted anywhere in the home. However, removal of a back boiler can cause disruption in your home because an engineer would be required to remove the old one from the wall. This can also add to the expense of replacing your boiler, so it can often be cheaper to install a modern combi boiler elsewhere in your home.
  5. A combi boiler could save space in your home. A back boiler requires two tanks which results in an inconvenient storage situation by taking up vital room in your home. A combi boiler however is a single wall-mounted unit; the compact and manageable size of a combi boiler makes it a suitable solution for most sized properties.

If you aren’t sure what combi boiler you would need in your home, it’s generally advised that the more radiators and bathrooms you have then the higher the output needs to be. If you have a high demand for hot water, then a high efficiency, condensing system or conventional boiler may be the answer. Find out more about boiler boilers and combi boiler brands here.


To find out how much a new back boiler replacement could cost you, get a quote online or call 0203 763 2682 .

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[28] Exclusions apply. See www.help-link.co.uk/fixed-price-quote-faqs/

[41] Source: energysavingstrust.org.uk

[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 autumn 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 www.help-link.co.uk and as long as the customer meets all the above criteria.