What boiler do I need?

Researching home boilers can be a daunting task. There is plenty of information available online but scrolling through the mass of search results for something as simple as “boiler types UK” may leave you feeling overwhelmed; especially if you are unfamiliar with boiler terminology.

But don’t worry; this beginners’ guide explains the main types of home boiler that are available and easy ways to help you decide which one you will need. It is designed to help demystify boiler vocabulary and to make next-stage conversations with your gas engineer more productive.

Let’s start with the basics which is to say that a boiler is a central heating unit that pumps hot water through the pipes around your home to your taps and radiators. If you are connected to mains gas – as most UK homes are – then you have a choice of three main types of gas-condensing boiler. These are combination boilers or ‘combis’, conventional boilers and system boilers.

Combination Boilers (Combis)

  • Water is heated on demand and a bulky water tank or a hot water cylinder is not required
  • Considered the best choice for small to medium size properties with average hot water demands
  • Energy is not wasted by heating water that may not be used, thereby reducing your heating bills and your carbon footprint
  • Quick and easy to install
  • The most popular UK boiler type

Conventional Boilers

  • Also called heat-only, open-vent or regular boilers, they provide central heating and hot water using an airing cupboard storage cylinder, and also require a cold-water storage tank plus an expansion tank in the loft
  • Featuring in most older heating systems they are slightly less efficient than combis, but are the ‘go-to’ choice for large homes with a high demand for hot water or multiple bathrooms, or for situations that already have a traditional heating and hot water system in place
  • On the downside they tend to be more expensive to install and take up more space

System Boilers

  • System boilers provide central heating and hot water using an airing cupboard storage cylinder but, unlike regular boilers, they do not rely on water supplied by a cold-water storage tank in the loft.
  • The hot water in the storage cylinder is always topped up ensuring hot water is always available which makes these boilers well suited to large, multi-bathroom properties with high hot water demands.
  • As well as saving space they are also easier to install than conventional boilers as many of the components are built into the boiler

Which type of home boiler is right for me?

You will be able to narrow down the best solution by answering some basic questions about your heating and hot water demands. These primarily relate to the size of your house and the number of people living in it. To help guide you, we have published an interactive tool on our website which takes you through a simple set of multiple-choice questions and answers. These cover all issues relevant to boiler selection such as: how your home is currently heated; what type of boiler do you currently have; is the new boiler going to be fitted in the same place; and how many bedrooms, baths, showers and radiators do you have.

This data, along with advice from a Gas Safe registered engineer, will make choosing your new boiler much easier. Whether you need a small boiler for a flat, a large domestic combi boiler or even a high efficiency fan-assisted condensing boiler such as ProTec Plus* for very large domestic projects with multiple bathrooms, Alpha can provide the answer.


* Available with outputs ranging from 50kW-115kW, ProTec Plus high efficiency fan-assisted condensing system boilers are ideally suited to large domestic projects and can be wall hung or fixed to free-standing frames.

Hydrogen-ready boilers

What does hydrogen-ready really mean and how will this affect you today and in the future? 

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