Gas Boilers – Choosing the Best Type for Your Home

27 Apr. 2019

Written by Neil Marsh MCIPHE RP RHP EngTech

The type of gas boiler used in a property can have a significant effect on energy consumption and overall performance. Consideration needs to be made into what type of gas boiler system is going to be installed … The properties design and the needs of the occupiers should dictate what system is best for a particular property. Installing the right system may lead to higher costs initially; however, the savings made through energy consumption alone can quickly recover these costs.

The main gas boiler types are:

  • Combination Boilers
  • System Boilers
  • Conventional Boilers

When purchasing a gas boiler for your property, we strongly advise you to find out more about various types of gas boiler systems as many companies out there are offering bad advice. 

A professional company such as FORTHRIGHT is your best choice as you need an experienced, educated company, that is honest to be able to offer you the best advice. Many companies will focus on what boiler is best for them to install and/or what they can maximise profits on, and others lack the knowledge or experience to advise you best.

Some of the factors that a quality installation company will consider when advising you on what type of boiler system to use are:

  • Mains water pressure
  • Water flow rates
  • The hot water usage and potential usage
  • How many people reside in the property on a regular basis and their bathing habits
  • The length of pipework to such thing as the taps and showers
  • The types of showers installed
  • The existing heating/hot water system and the pro’s and con’s of installing each type of system
  • Costs
  • Space available
  • Total disruption


Elaborating on the kinds of gas boilers:

Combination (combi) boilers: These provide heat and hot water with no need for water tanks or cylinders. Cold water passes through the boiler and is heated instantaneously, it supplies hot water on demand in unlimited supply. These boilers are best suited where the hot water needs within a property are low. Modern condensing boilers, despite the common conception, often only run at efficiencies of 60% in hot water mode and this can lead to an increase in energy consumption over stored hot water systems (such as cylinders) in properties where hot water is used in higher amounts. Combi boilers provide hot water at mains pressure and flow rates. The flow rates available at the property will, when installed correctly, dictate the kilowatt rating (size) of the boiler. A combination boiler does offer a space-saving design over a storage system which can offer advantages in properties with limited space. Water flow and pressure will often reduce noticeably if more than one draw point such as a tap is opened at the same time, how much will depend on system design, water pressure and flow rates. If the combi boiler becomes non-operational, you will have no way to produce hot water from the system so having an electric shower in the property is beneficial.

System Boilers: These boilers operate in the same way as a conventional boiler, except they have several components that are usually external that are built integrally to the boiler. They are designed to be used on a sealed system (pressurised). The primary purpose of a system boiler is to save space and is best suited to smaller to medium size properties due to limitations of the pump and expansion vessel.

Conventional Boiler (heat only): These boilers provide heat that can be distributed to cylinders to heat water and/or heating components, like radiators, via external components such as pumps and valves. These boilers can be installed onto both open (gravity fed) systems and sealed systems. Conventional boilers are suited to properties of any size, however, smaller properties may lack the space to accommodate components such as cylinders that are required for hot water. A well installed conventional boiler system can achieve efficiencies as much as 95% in both heating and hot water mode. Immersion heaters can be installed on cylinders to provide a back up for hot water should the boiler, or one of the external heating components fail.

All modern boilers in the UK are higher efficiency condensing boilers. However, their operational efficiencies are effected by the design of the systems they are installed to. To maximise the efficiency of the boiler and system overall, the system and components, such as controls, need to carefully designed and the best practices for use need to be explained to the user.

Only a quality company like FORTHRIGHT can advise and design systems that are best suited to a property. Do not be fooled into thinking that all heating companies are equal, many are not able to design systems that will perform efficiently and that are durable. Contact Forthright for boiler installations in Gloucester, Cheltenham, Tewkesbury and the areas surrounding.