The Environmental Impact of Boilers: Green Solutions for Home Heating

The last gas boiler may be installed in the UK by 2035 to meet the government’s ambitious Net Zero Carbon Emission goal of eliminating greenhouse gas emissions by 2050.

While gas boilers are incredibly efficient and arguably the best solution for UK citizens because of the low running costs, there may come a time when everyone needs to switch to a green home heating solution.

Before discussing green heating solutions for your home, we need to focus on the environmental impact of current fossil fuel boilers

The Environmental Impact of UK Boilers

According to data published by The Guardian, gas boilers in UK homes produce twice as many greenhouse gases as all the gas-fired power stations combined.

Alarmingly, home heating is responsible for about 38% of gas used in the UK, and an average home boiler emits 2.2 tonnes of CO₂ a year.

UK homeowners still rely heavily on fossil fuels to heat their homes, but which are the worst offenders regarding carbon emissions?

Let’s start with the UK’s most popular heating system fuel.

Gas Boilers

Gas boilers are the most popular heating system in the UK, with 75% of residential heating energy consumption being gas.

The high volume of gas boilers in the UK has created a significant carbon problem, with estimates indicating that around 68 million tonnes of CO₂ are emitted into the atmosphere annually.

Currently, 14% of the UK’s total carbon emissions are due to home boilers.

It’s worth mentioning that newer models are more efficient than older ones. New condensing boilers release up to 10 to 20% less CO₂ than older boilers. By capturing wasted heat via the flue pipes, condensing boilers can lower fuel consumption and emissions.

Oil Boilers

While not a common heating source in the UK, oil boilers are usually found in more rural areas without access to the gas grid.

A single oil-fired boiler can emit four to six tonnes of CO2 per household annually, making it twice as inefficient as modern gas boilers in terms of carbon emissions.

The fuel it burns is a primary reason for its high greenhouse gas emissions. Kerosene and heating oil are carbon-intensive mediums.

While the total emissions from oil boilers are unknown, as there aren’t enough numbers to conduct proper surveys, it’s clear they are not a green heating solution.

Electric Boilers

An electric boiler does not emit greenhouse gases and can, in the right circumstances, be a green heating solution when combined with an alternative energy source like solar.

However, without solar, electric boilers need electricity from the grid, which indirectly contributes to carbon emissions when generated via fossil fuels such as natural gas or coal.

As the UK grid becomes more decarbonised annually, emissions will improve in the future.

According to the UK government, the country is one of the first major economies to have successfully halved its emissions by 50% between 1990 and 2022.

Renewable energy sources now account for more than 40% of the country’s electricity.

The UK government is making active strides to produce more environmentally friendly energy.

It’s worth noting that the government has also launched a few grant programmes to help citizens adopt more environmentally friendly energy solutions.

UK Government Grants for a Greener Future

The UK government offers grants to eligible households so that they can replace old, inefficient boilers with more energy-efficient solutions.

Two viable government grant schemes exist currently: the Energy Company Obligation (ECO) and the Boiler Upgrade Scheme (BUS). While there used to be a third option, the Renewable Heat Incentive (RHI) scheme, it is currently not accepting new applicants.

To apply for the available grants, you need to meet specific criteria.

The ECO Boiler Scheme

In 2012, the UK parliament passed the ECO Boiler Scheme. The ECO Scheme, also known as the free boiler scheme, aims to reduce the UK’s overall energy consumption by providing lower-income households with more energy-efficient methods of heating their homes.

The country’s largest utility companies are required to participate, including:

• British Gas
• EON
• EDF
• Octopus
• OVO
• Bulb
• Scottish Power
• And others

The grant’s main focus is to replace older non-condensing boilers. As we’ve mentioned, condensing boilers are designed to reuse the heat in their flues, which can reach temperatures of up to 200°C.

The BUS Scheme

The other grant available to residents in England and Wales is BUS. BUS is designed to help certain homeowners switch their heating source from fossil fuels to more environmentally friendly solutions.

To be eligible for BUS, you must be a property owner who would like to replace their older fossil fuel system. You will need the assistance of an installer who must ensure that their work is completed within 120 days from the application of the grant.

If you have already received assistance from another grant to make your home more energy efficient, you can still apply to BUS.

Another requirement you need to be aware of is your home has to have an installation capacity of up to 45kWth (kilowatt-thermal), which is a measurement of potential heat output from the installed system.

The BUS provides funding for three low-carbon heating systems, which include:

• £7500 towards the cost and installation of an air-source heat pump system.
• £7500 towards the cost and installation of a ground-source heat pump. The contribution must also cover water-source heat pumps.
• And £5000 off the cost of installing a biomass boiler.

But what exactly are these new green solutions for heating your home?

Green Solutions for Home Heating

Before we highlight the green heating solutions for your home, you need to be aware that most of these technologies are going to improve in the future. Also, many of these green solutions will require a large lump sum of money.

Also, some of these newer heat sources can be complex to install and require specialists.

Let’s review what your options are:

Air Heat Pump System

As eligible homes are potentially able to claim £7500 towards the cost and installation of an air heat pump system, it is a tempting green heating solution for many citizens.

If you want to understand how an air heat pump system works, a simple analogy is to think of it as working in the opposite manner of a fridge.

Rather than absorbing heat from the appliance and expelling it, the system’s pipe network extracts heat from an ambient environment, retains it, and uses this captured energy to warm your home and water.

For those concerned about it working in more frigid conditions, air heat pumps can operate easily at least -10°C, while some more durable units can work in temperatures as low as -25°C.

Air heat pumps are also incredibly efficient compared to other heating technology, with a 400% efficiency rating. To install an air heat pump system, you will need enough outside space to ensure adequate airflow for it to capture the heat.

It’s worth remembering that currently, air heat pump systems are not completely carbon emissions free, as the system requires an electricity source to pump the heat capturing fluid.

Also, there is no manufacturing process for this system that is completely carbon emissions free. However, running this system for your home will dramatically reduce your carbon footprint compared to running a gas boiler.

While air heat pumps are generally efficient, depending on the household’s needs, they can become a little less efficient.

Lastly, air heat pumps are known for being a bit noisy; think about your home’s current fridge. While not an extremely loud appliance, you can hear it operating when all is quiet in the household.

Geothermal (Ground Source) Heat Pump

Sometimes referred to as a ground-source heat pump, this is an incredibly efficient method of heating your property. And with the change in seasons, it can also be used to cool the home.

As you’d guess by the name, the system works by circulating a mixture of water and antifreeze into a network of pipes buried in the ground. While we may not think about it often, soil, dirt, or any ground substance, captures heat and cold incredibly well, making it a natural thermal energy bank.

This means that when water is circulated underground, it is able to capture this retained energy (hot or cold) from the ground and distribute it around the home. However, it is worth noting that what energy you capture is heavily dependent on the season.

And in the depths of winter, the system can use a refrigeration cycle to up the desired temperature.

Also, geothermal heat pumps are incredibly efficient, being able to reach efficiency ratings of between 300% and 600%, even in the coldest conditions. In fact, in Norway, 29,745 heat pump systems have been installed.

And if you’re looking for a long-term investment into green energy solutions, the underground piping system can last over 50 years, with the pump unit having a shelf life of around 20 to 25 years.

Also, when compared to an air pump, this system operates very quietly.

However, compared to Norway, which produces nearly 100% renewable energy thanks to its extensive hydropower plants, the UK falls behind by still relying on fossil fuels. This means, that no geothermal heat pump system installed in the UK will be 100% carbon emissions free, as it requires electricity to operate.

While the UK government will help with installation costs, geothermal heat pump systems are extremely expensive, and require enough land with the correct soil composition to be installed.

And lastly, it cannot be installed in urban environments.

However, there is an alternative green energy source that can assist with making these systems’ emissions rating even lower.

Solar Boiler And Heating

A solar boiler works via a system of solar collectors, which are tubes filled with glycol fluid installed on your home’s roof.

How this solar boiler works is, the sun heats this fluid, which circulates into a storage system where it is stored until it can be used or circulated back to the roof if the temperature in the storage tank drops.

Solar heating systems require little to no maintenance. However, they do not work in colder conditions or extremely overcast conditions. Also, because of the climate in the UK, most solar hot water tanks do require an additional boiler system.

But, if that system is a heat pump, then you could be well on your way to a greener heat source.

Also, it is worth mentioning that a solar boiler will not produce energy that can be used to power appliances. This will require the installation of a different type of solar system panel, which is a low maintenance source of energy.

However, if you can afford to install a solar power system with a battery storage bank to power your heat pumps, you’ll be far ahead of the green heating solutions curve.

But for those looking for an environmentally green solution that requires burning fuel, then the next option is for you.

Biomass And Biofuel Boiler

While the name biomass or biofuel boiler will potentially paint an image of a fantastic future fuel, it is simply a wood burning device that uses wood or any other natural renewable fuel source to generate heat.

It may be confusing, but wood is a sustainable resource we can manage effectively to ensure it is always around.

However, as we all know, burning wood releases carbon. But burning wood only releases recently captured carbon dioxide back into the atmosphere. When we burn fossil fuels, we’re releasing carbon dioxide that was captured millions of years ago, emissions that should have stayed in the ground forever.

At the end of the day when you burn wood, it is carbon neutral. Installing a biomass boiler that uses other resources such as methane gas, ethanol, and biodiesel fuels is also possible but will be a costly exercise. However, if you qualify, you can apply for a government grant to help finance it.

Just be aware, running a biomass boiler can be expensive and will also require regular maintenance.

While this old-school solution is a green one, you can also upgrade your current boiler to accept hydrogen.

Hydrogen Ready Gas Boilers

Hydrogen (H₂) is a gaseous fuel that uses infrastructure similar to LP gas. Which means, given the motivation, it could be piped through current infrastructure.

But to be transparent, the National Infrastructure Commission has highlighted there is no public policy case for hydrogen to heat individual buildings and therefore, there is no grant, or a drive to push this technology.

Retrofitting older boilers to use H2 could lower costs and carbon emissions. In fact, burning hydrogen does not produce carbon emissions. Its by-product is actually water.

At the moment, hydrogen-only boilers are in the prototype stages of development; however, if you are really keen to invest in this technology, hydrogen-blend-ready units are widely available.

As a champion for affordable heating solutions, WarmZilla can assist you select a hydrogen-blend-ready unit, or a new incredibly efficient gas boiler that could be retrofitted to keep up with the government’s policy goal for Net-Zero Emissions by 2050.