Our Pages

Boiler Efficiency Rating

Boiler Efficiency Explained

The energy efficiency rating of a boiler serves as a crucial factor in determining its operational cost. It provides a valuable means of comparing different boiler models to ascertain which one will yield greater savings on your energy expenses. If you’re presently reliant on an outdated boiler, upgrading to a modern, energy-efficient alternative could significantly reduce your utility expenditures.

What are SEDBUK Efficiency Ratings?

Between 1999 and 2015, boilers were assessed using the SEDBUK scale, which represents the ‘Seasonal Efficiency of a Domestic Boiler in the UK.’ Even though SEDBUK 2009 and 2012 were superseded by the Energy-related Products Directive (ErP) in 2015, numerous manufacturers continue to make reference to SEDBUK because it provides a more comprehensive and detailed efficiency rating.

What Is The ErP Directive?

The ErP Directive was established in response to the European Union’s goal of enhancing the energy efficiency of residential buildings and accomplishing the following objectives by the year 2020:

In adherence to the prevailing ErP standards, boiler manufacturers must affix a label to their products, displaying an efficiency rating ranging from A+++ to G, with G signifying the least efficient.

How to Choose the Most Energy Efficient Boiler?

However, a drawback of the ErP system is that it often assigns an A rating to most modern condensing boilers, leaving homeowners with limited differentiation when seeking the most efficient model. In contrast, the SEDBUK rating system quantifies efficiency as a percentage, typically ranging from 70% to 92%, reflecting the balance between energy utilization and wastage during home heating. Consequently, many homeowners prefer to evaluate potential new boilers based on their SEDBUK efficiency rating rather than relying solely on the more recent ErP energy label. You can find modern, A-rated condensing boilers available in various types, including combi boilers, system boilers, or conventional boilers, tailored to your home’s central heating system.


How Much Money Could I Save with a More Efficient Boiler

To grasp how a new boiler can lead to cost savings, it’s essential to consider the energy wastage associated with an inefficient boiler. For instance, if a boiler operates at only 70% efficiency, for every £1 spent on heating your home, 30p is lost as wasted energy. However, if your new boiler achieves an efficiency of 90%, the waste is reduced to just 10p for every £1 spent. This translates to a saving of 20p in every £1, which accumulates significantly over time.

While the ErP directive became effective in September 2015, the UK government’s Boiler Plus legislation, implemented in April 2018, raised the minimum efficiency requirement for all gas boilers manufactured and installed in England to 92% (ErP). Additionally, the regulation mandated the incorporation of additional heating controls to empower homeowners with maximum control over their energy consumption:

  1. Time and temperature controls are mandatory for all gas and oil boiler installations.
  2. Combi boiler installations must include one of the following: Weather compensation, Load compensation, Flue Gas Heat Recovery, Smart controls.

The potential financial savings resulting from replacing your boiler with a more efficient model can be substantial. However, the exact amount saved will depend on factors such as your home’s size, the type of fuel used by the boiler, and the inefficiency of your current boiler.

On average, households that upgrade from an old gas boiler (equipped with a standard programmer and room thermostat) to a new A-rated condensing boiler with a programmer, room thermostat, and thermostatic radiator controls (TRVs) could achieve savings of up to*:


Boiler Efficiency and The Environment

Boiler efficiency isn’t solely about financial savings; it also has a significant environmental impact. An inefficient boiler, one that consumes more fuel than necessary to heat your home, contributes to higher carbon emissions in the atmosphere. Natural gas and oil, which are commonly used fuels for heating, release carbon dioxide when burned.

Carbon dioxide is a greenhouse gas, and the elevated levels of it in our atmosphere contribute to global warming. This rising temperature is responsible for shifts in our climate, leading to increasingly unpredictable and extreme weather events like ice melting, rising sea levels, and eventual flooding. If substantial measures are not taken to combat climate change, both humans and wildlife will face escalating challenges in inhabiting our planet.

The fossil fuels we burn, whether for industrial purposes or home heating, are a major driver of climate change. Therefore, it is imperative that we minimize our carbon footprint as much as possible. Utilizing the most energy-efficient boilers is essential, but the ultimate goal is for the UK to seek alternative renewable heating solutions that do not release carbon into the atmosphere.


Renewable Heating Alternatives

While fossil fuels are finite resources that deplete and release carbon into the atmosphere, renewable energy derives from natural sources that replenish within human timescales. Furthermore, renewable energy sources are typically carbon-free or carbon-neutral. Renewable heating systems often come with low operating costs because they harness free resources, resulting in reduced energy purchases from suppliers and, in many cases, lower heating bills.

For instance, heat pumps extract latent heat from the air, ground, or water from lakes and rivers and use it to heat water or air for household use. Solar thermal panels capture energy from sunlight to generate hot water. Biomass boilers, similar in function to gas and oil boilers, burn wood pellets or similar materials to produce energy. Importantly, this process is carbon-neutral, meaning that the pellets do not emit more carbon than was initially contained within the trees from which they were sourced.