Save energy, money & the planet: increase your household’s boiler efficiency and offset your carbon emissions


The energy used by the UK’s 29 million homes accounts for 14% of its total carbon emissions and the main culprit is one of our most essential household items – boilers, commonly fuelled by either gas or oil. Boiler inefficiency is the key issue when it comes to carbon emissions.

Learning how to make your boiler as efficient as possible will reduce CO2 emissions, save energy, and reduce your energy bills. Here, with some help from Mark Glasgow, Managing Director and Owner of The Edinburgh Boiler Company, we discuss your boiler’s emissions, as well as what you can do to optimise its efficiency and offset your emissions to contribute to the fight against climate change.

Boiler efficiency explained

Boiler efficiency is measured by how efficiently your boiler turns its fuel into heat energy. Essentially, an efficient boiler uses the least amount of energy and money and produces fewer carbon emissions. It’s a win-win situation for both you and the planet.

You can measure your boiler efficiency at home by looking at the percentage of energy your boiler uses to heat your home. A study conducted by The Edinburgh Boiler Company shows that if you buy a new boiler that is 94% efficient, which is the standard, your appliance will use 94% of the supplied energy to heat your home. The remaining 6% will be lost, which is about 1.44kW.

Money-wise, you will be losing about £0.05 per hour*, and planet-wise, your boiler will exert about 0.26 kWh of excess gas (carbon emissions). Over a period of one year, that totals a wastage of 525.6kW, £19.97*, and 96.7kWh of gas.

What is boiler efficiency dependent on?

The example above is based on a new boiler used for one hour a day. However, if you increase the use of that same boiler to five hours a day, you will be losing about 7.2kWh, £0.27*, and 1.32kWh of gas a day.

If you have a household that demands more heat and hot water and you need to use the boiler for eight hours a day, you’ll be looking at 11.52kW wasted energy, which is about £0.44* and 2.12kWh of excess gas emissions a day. Over one year, that equals 4,204.8kW, £159.78*, and 773.68kWh of gas.

The thing that impacts your boiler efficiency the most is its age. This study shows that if you have a 10-year-old boiler, it will be wasting more than double the energy, pennies, and carbon emissions. If you’ve had your boiler for more than 25 years and you’re using it for eight hours each day, it’ll waste 28,032kW, which equates to about £1,065.22* and 5,157.89kWh of excess gas.

What’s the solution?

Of course, limiting your boiler use would save you energy and money and reduce your household’s carbon emissions. However, it’s not a viable solution for everyone because heat and hot water are household essentials.

Despite our tendency to hold onto things in order to save money, the study proves different. If you service your boiler regularly and replace it when it becomes inefficient, it is likely to be more cost-effective in the long run.

But it’s not all about money. Our planet is a direct victim of boiler inefficiency. When your appliance uses more energy than necessary to heat your home and water, it is producing more carbon emissions. When fossil fuels such as gas and oil are burnt with oxygen, they produce CO2, which is a greenhouse gas that contributes to climate change.

According to several studies, fossil fuels create the highest level of carbon emissions, which makes them the leading contributors to climate change. In order to minimise this issue, we can all try and use our boilers as little as possible, replace our old boilers with news ones when they become inefficient, and invest in renewable heating solutions, such as electric boilers, when we replace them.

How many trees are needed to offset the CO2 produced by your gas boiler?

Deforestation is also heavily contributing to increasing carbon emissions and climate change. When a tree is cut down, it not only stops absorbing carbon from the air but it also releases the carbon it has been storing. Since trees and forests are the lungs of our planet, soaking up tons of CO2, deforestation results in more greenhouse gas emissions.

The UN Food and Agriculture Organisation (FAO) has estimated that about 178 million hectares of forest were destroyed between 1990 and 2020. That is almost the equivalent of Libya’s total surface area. Due to deforestation, tropical forests now emit more carbon than they absorb, a 2017 study found.

To put things into perspective, you’ll need to grow 12.8 trees over 10 years to offset the use of a new boiler for eight hours every day per year. But for a boiler that’s over 25 years old, you’ll need the equivalent of 85.1 new fully-grown trees to counteract your boiler’s carbon footprint for a year.

Although our eco-consciousness is on the rise, the effects of our boilers on climate change might have not yet appeared on our sustainability agenda. But being aware of how we can increase our boiler efficiency is key to combating these pressing climate issues. One small step at a time and one tree planted at a time, we are doing our bit for the environment.