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  • Writer's pictureDan Kelly


Updated: Sep 15, 2021


Climate Change (CC) is of the most problematic phenomena and the environmental Armageddon of our time. This is primarily due to the production of Greenhouse Gas Emissions (GHG) from a multitude of sources that are often anthropogenic. GHG emissions are detrimentally challenging as they contribute to the gradual warming of the planet. The gases absorb solar energy from the land and ocean which is then radiated and gradually released back into the Earth. In turn, thermal heat is trapped within the atmosphere that securely blankets us and is ultimately tipping the energy budget. This is known as the Greenhouse Effect. The toxic combination of gases that mainly formulate GHG are Methane (CH4), Nitrous Oxide (N2O), Fluorinated Gases and Carbon Dioxide (CO2) [1]

CO¬¬2 is causing prime concern as it is contained within the atmosphere for a much longer time. This gas typically enters the atmosphere through fossil fuel combustion such as the burning of coal or oil. The thermal energy generated from this process is purposed for electricity and heat. But the harmful impact this has on global health, climate and the environment make you wonder, is it all worth it? Especially as they can be substituted by utilising renewable sources and the use of fossil fuels can be abolished. This transition is significant as CO2 concentrations continue to climb and are etching us towards an unrecognisable future [2] Therefore, methods of sustainable living must emerge and be conducive to a zero-carbon or carbon-neutral existence.


Let’s look at this impact a little closer to home. In the UK, we contribute 1% global total GHG emissions (Figure 1) [3]. And strangely, 1% is still a sufficient amount to warrant changes to current systems. However, since 1990 the UK have made dramatic improvements and achieved a decrease of 49% in emissions with the credit owed to better waste management resulting in a 71% decrease and the exchange of coal for renewables in the energy sector. [4]

Figure 1: GHG emissions per country. Source: Union of Concerned Scientists (2020) Data: Earth Systems Science Data 11, 1783-1838, 2019

Our recent situation has seen positive alterations, surprisingly, related to the ongoing COVID-19 Pandemic and the resulting restrictions. This has caused a dip in oil and coal demand but also expanding renewables in some sectors [5]. UK CO2 emissions in 2020 have had a slightly drastic fall from 2019 with a decrease of 10.7%. This is mainly due to the transport sector which has had little change since 1990. This is the outcome of restricted travel and the number of furloughed employees. On the other hand, GHG emissions in the residential sector have risen by 1.8%. This is the effect of people staying at home, using their fossil-fuelled appliances for heating and cooking.[4]


As you can see, the UK need a strategy. But what are they currently doing about this?

As previously mentioned, the government have a goal of reaching ‘Net-Zero’. This means to achieve a balance between the production and removal of GHG emissions from the atmosphere meaning created emissions need to be fully offset. The government have produced legislation and numerous initiatives on their ongoing road to net-zero. The Climate Change Act (2008) is an example, originally aiming for an 80% reduction in GHG emissions compared to 1990 levels by 2050, the government have since amended this to reach net-zero by this time. Additionally, to this, a 2025 target has been set to reduce emissions by 51% and also a 57% reduction in 2030[6]. The statutory body, the Climate Change Committee (CCC) have stated that the UK are currently not on track to meet these goals and need to implement certain measures to adapt. To align with net-zero targets, the government need to set consistent policy, regulations and make a practical plan for each sector on how emission reduction is to be achieved. As an example, for the ineffectively energised buildings of the residential sector, the government should take action by retrofitting existing and building new homes to meet low carbon standards with additional secure funding dedicated to low carbon heating [7]. To progress in this direction, in 2019 the then-chancellor Phillip Hammond announced a ban on the installation of gas or oil boilers in newbuild houses by 2025 with the ambition to install 600,000 heat pumps by 2028. [8] [9] Unfortunately there is no plan to implement a low carbon policy on existing homes, however incentives and government grants have become available to aid this shift. In addition to government aids, there are changes as a resident, you can make to your current heating system with a range of low carbon options to choose from. You can be in control of ensuring your home is efficiently energised.


Now after digesting the issue we currently face, you may be curious as to the alterations you can make to your home heating in order to reduce your carbon footprint and which low carbon heating options are best to do this.

Ground Source Heat Pumps

Ground source heat pumps (GSHP) are one of the most efficient options for your home and the process is intriguing. Within this operation, an abundance of heat is transported from the ground, concentrated and released into your home for warmth or hot water, allowing you to take advantage of the earth’s natural heat throughout the year. But how does this really work? Let’s break it down. The ground absorbs low grade energy from rain and sunlight. A series of pipes known as the ground loops are imbedded within the soil, with an antifreeze solution circulating around them and soaking up the natural heat. The heated mixture is fed into a heat exchanger (also known as the evaporator) where the energy is absorbed and transferred to a refrigerant liquid which, when reaching a boiling point, becomes a gas. The temperature of the gas is increased in the compressor before passing through a secondary heat exchanger and finally transferred to purpose your home [10] This is a very stable and cost-effective option with 4KW of energy generated for each KW consumed, meaning the costs per KW/h is quartered!

Air Source Heat Pumps

Air source heat pumps (ASHP) may be a better option if you want less disruption to your garden. This pump uses an ultra-quiet fan to draw in the outside air. Similarly to GSHP, this system uses a liquid refrigerant and a heat exchanger to absorb heat from the air. The heat can then be used in the home’s radiator system or stored in a water cylinder to be utilised for hot water [11]. This is a brilliant environmentally structured machine, and if not for the electricity used to power this, it would be perfection. But don’t let that deter you, the energy output generated is far greater than the electrical input. Additionally, costs for pumps vary but are however eligible for government grants. Fortunately, any homeowner with a garden space can benefit from both ASHP and GSHP.

Solar Thermal Panels

Solar thermal panels obtain heat from the sun to warm fluid for hot water and heating (Figure 2) There are two main types of solar heating panels, flat plate or evacuated tubes. The latter being more resourceful and smaller in size. The initial cost is lower than that of pumps with minimal additional costs. The cost of maintenance may be a little pricey, but it is a very low maintenance system with a life span of 20 years or 30 in some cases. On a sour note, you will still need a boiler or immersion heater to make the water hotter or to provide hot water when solar energy isn’t available. [12] These panels work best on a south facing roof at a 30° angle that is not obstructed by shade. Furthermore, your roof will need to withstand the heavy weighted panels which your installer can advise you on.

Figure 2: The process of solar thermal panels. Source: Which.

Hybrid (Dual Fuel)

If you or your finances are not ready to make the leap to a net zero heating system, then why not venture into a Hybrid system? A hybrid or dual fuel system combines a renewable source, typically ASHP with your traditional existing boiler (you will need to have an existing oil or gas boiler to be eligible). To adhere to a set temperature, the systems will switch depending on which is most effective at the time. This is a flexible choice that will reduce both environmental and economic costs whilst maintaining consistency in your home’s temperature. Furthermore, this reduces your dependency on gas or oil boilers and prepares you for a complete renewable system in the future. Although this is certainly a step in the right direction it does not fully aid a net zero future so the above options should be strongly considered first. [13]

Biomass Boilers

This strips us back to the basics by generating heat from organic matter, typically wood in the form of pellets, chips or logs. The organic matter is burned in a combustion chamber to form hot gas and air that travels through a flue. The heat exchanger then transfers the produced heat to the properties central heating system. Excess heat is stored in a thermal tank also known as the buffer vessel. There are various types of biomass boilers that may be suited to your situation and needs. You may even want a simple wood burning stove that heats only one room. The installation of this boiler has various requirements so it may not be suitable for every home but most importantly a decent amount of space is needed to house boiler and additional parts such as buffer vessel. The is a simplistic solution and depending on the type of biomass boiler, is a profitable choice as it’s also eligible for government grants. Having said that, studies exist that give indication of the potential air pollution of nitrogen oxides this produces. [14]


Insulation in your home is a resourceful way of retaining heat which ultimately keeps cost of bills and energy down as insulation of loft, cavity and solid walls decreases the amount of heat lost through roofs, walls and floors, meaning less energy is required to heat the building [15]. Additionally, there will be less environmental impact with less pollutants being released. The decreased use of your heating will also give you a good EPC (Energy Performance Certificate) rating, making your home more attractive to potential buyers. And notably, insulation can benefit your mental and physical health. Various studies have found that insulation retrofits have aided health, especially with improvements to respiratory conditions. It has also been linked with reducing asthmatic wheezing in children. Moreover, the thermal satisfaction of being warm and cosy will ease your mentality [16].

The government are working to increase insulation levels to further contribute to their carbon targets. By the end of 2020, it was estimated that 32% of homes with lofts were uninsulated and 91% of homes with solid walls were uninsulated, while 70% of homes with cavity walls were insulated. The lack of insulation in solid walls is likely due to the costly nature of this process, forcing the government to potentially discontinue with solid wall insulation [17]. According to the CCC, government insulation measures are 95% lower than 2012 [18]. However, current schemes continue to improve and encourage energy efficiency in homes.


Many government grants have supported the low carbon heating transition. However, some have now desisted but are still worth mentioning. Firstly, the Green Deal launched in January 2013 and ran until July 2015 when the government halted their support for the Green Deal Finance Company. This scheme provided loans for numerous heating systems. To name a few; replacement boilers; insulation; GSHP; and ASHP. Some maintenance costs were also covered. The loans were then paid back via your electricity bill. Since its termination, other energy companies have adopted this idea [19]. The Green Homes Grant (GHG) is another prime example. This scheme began in September 2020, following the Prime Ministers ‘build back better’ strategy. This would help economic recovering in the wake of the pandemic and create green jobs. The £1.5 billion programme provided household grants for up to £5,000 or £10,000 to cover 2/3 of the cost to make household energy efficient improvements to your home. This scheme was scrapped just 6 months in. This may wound the country’s credibility in the upcoming Cop26 UN climate talks to be hosted by the UK this November. [20] [21]

Local Authority Delivery Scheme (LAD)

This £500 million scheme was launched in August 2020 and funds energy efficiency and low carbon heating projects for low-income households across England. As stated by the government, this is being delivered In 3 phases.

• Phase 1A: Allocated grants of over £74 million for 55 projects which will upgrade energy efficiency of 10,000 low-income households in over 100 local authorities by 2021.

• Phase 1B: £126 million will be allocated to 81 local authorities to deliver energy efficiency project by September 2021 with an aim to upgrade 15,000 homes.

• Phase 2: £300 million has been allocated to the 5 local energy hubs who will work alongside their regional local authorities to continue energy upgrade to up 30,000 homes that need it most, until December 2021.

The local energy hubs are based in 5 areas, South East, South West. Midlands, North East, North West [22] As a case study example, Devon County Council have been successful in applying for the grants schemes in their areas. [23]

ECO (The Energy Company Obligation)

The Energy Company Obligation (ECO) scheme came into effect in April 2013, with amendments to it since then. The latest iteration of the scheme focuses on targeting energy efficiency measures in lower income and more vulnerable households. The latest policy and the fourth phase of the obligation is ECO3 which launched in December 2018 and will run until 31 March 2022. [24] The ECO scheme means that medium/large gas and electricity suppliers are obliged to help households with energy efficiency measures. These measures available through ECO include:

• Insulation – loft, cavity wall, solid wall and under floor.

• Boiler replacement or repair. [25]

This helps save on energy bills, keep homes warmer and reduces emissions. This scheme is ideal if you are a low-income household or are a consumer vulnerable to the impact of a cold home including elderly, disabled and families. And also, if you are living in a social housing property with energy efficiency ratings of E, F, or G. [26]

Domestic Renewable Heat Incentive (RHI)

This is a government financial incentive that began in 2014 and has helped many. The resident receives quarterly payments for seven years, provided they abide by the rules set in this incentive. With this, you can claim for biomass boilers, solar water heating and heat pumps. There are numerous requirements to meet to be eligible. You can find more information on the requirements here. But it primarily applies to people that own the homes they live in, social and private landlords for properties where one heating system only serves a single household, tenants, and people that build their own homes, or have them built for them and meet certain other requirements. Moreover, to join the scheme you must have an EPC that is less than 24 months old to prove your property is a domestic residence. If you have hopes of installing a heat pump, you’re in luck.

So now that you know you’ve been provided with tools to install your energy efficient heating system, which one will you choose?




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