Combi Boiler and Radiator Installation: What To Expect

Combi boilers are the most popular and common choice of boiler in the UK. This is because they are compact, simple to install and efficient at producing hot water. If you’re considering a new Combi boiler installation and also require new radiators, here’s everything you’ll need to know.

Combi Boiler Installation

Before a combination boiler installation, it is a good idea to request at least three different quotes from local engineers, as installation prices can vary hugely from company to company. You should be prepared for a Gas Safe registered engineer to assess your home.

After the assessment, they should be able to offer advice on the best kind of Combi boiler for your requirements, based on the number of bathrooms, number of bedrooms and size of your household. An initial visit from an engineer will also provide them with an opportunity to note down what equipment they will need for the job.

Choosing The Right Combi Boiler

Combi boilers are available in a variety of sizes and outputs, measured in kilowatts (kW). The right boiler for your home will depend on how much hot water your household uses. If you have multiple bathrooms, for example, a small Combi boiler might struggle to supply each bathroom with hot water at the same time.

– For a small flat or terrace, a Combi boiler between 24-27kW should suffice.
– For a medium terrace or semi-detached house, a Combi boiler between 28-43kW should suffice.
– For a large detached house, a Combi boiler between 35-4kW should suffice.

Choosing The Right Gas Safe Engineer

To legally work with gas appliances, a heating engineer must be listed on the official Gas Safe register. You can check the credentials of an engineer on the Gas Safe website, or alternatively ask to see their identification when they attend your home.

This will provide you with peace of mind that your engineer of choice is competent to complete a Combi boiler and radiator installation in your property.

Manufacturer Accreditation

Some Combi boiler manufacturers operate their own accreditation schemes where they recommend specific engineers to install their products. These engineers have usually demonstrated their knowledge of the manufacturer’s boilers, and choosing to use an accredited engineer could even entitle you to a longer boiler warranty.

Preparing for Combi Boiler Installation

Once you’ve decided upon a suitable boiler and given the engineer the go-ahead to proceed, you might want to be prepared to cover any carpets or surfaces so that your belongings aren’t damaged during the installation process. A capable engineer should bring their own coverings, and they might even perform a “power flush” on the existing pipework infrastructure. This will help to clear the system of any debris or rust prior to connecting the new boiler. Many engineers offer this service as standard, although some may charge extra. Regardless, power flushing is a good idea, because it ensures your new Combi boiler is being installed onto a ‘clean’ pipework system, which will minimise the risk of it becoming clogged with debris in the near future.

If your existing boiler is already a Combi, your engineer might be able to finish the installation within a single day. However, if you are switching out for an older type of boiler, or installing a completely new central heating system, the work may take a little longer.

Radiator Installation

If you are replacing existing radiators without changing their location, a simple like-for-like radiator installation should only take a couple of hours. A qualified gas engineer should bleed and test the radiator system after your new radiators have been installed, to ensure there are no errors. In some instances, they may also need to top the central heating system up with water – although this will depend on how much water is lost during the process of removing your old radiators.

Additional radiator installation could prove slightly more complex, depending on the amount of pipework required and the accessibility of any existing pipework. If it’s a first-time central heating installation, you could expect the work to be ongoing for several days. This is because pipe installation is generally performed under the floorboards, which can be a complex and time-consuming task. A complete pipework overhaul throughout the entire home could cost anywhere up to £1,000, although if existing infrastructure is already installed and there are no issues with leaks or blockages, your engineer will most likely recommend that you save money and time by utilising the existing pipes.

From a financial perspective, it’s worth remembering that radiators are available in a variety of styles and sizes, which will affect how much the overall installation will cost. Larger radiators may also take longer to install, which could result in a slight increase in labour costs.