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We carefully consider the needs of our customers and the impact on the environment, both from the construction of our homes and from our homes in use. We take all reasonable measures to minimise our impact on the environment, whilst balancing the need to deliver affordable, quality homes.

Carbon Emissions

The built environment contributes around 40% of the UK’s total carbon emissions, with around half of this being from “in-use” sources, such as heating, lighting, cooking and running appliances1.

This has reduced over the years as the UK moves towards decarbonising the electricity grid, with total in-use emissions having reduced by about a fifth since 1990 despite there being approximately a quarter more homes.2

This will continue with the government’s Future Homes Standard; which commenced in 2021 with interim updates and the next of these changes to Part L, Part O and Part F of the Building Regulations setting new energy and ventilation requirements from 2025.

These changes will continue to improve the energy performance of new homes, with homes being highly energy efficient, with low carbon heating, and ensuring they are zero carbon ready.

We recognise the impact that the built environment has on carbon emissions, both from the construction of new homes and in-use emissions. We are working hard to reduce our carbon footprint and this strategic priority is part of our sustainable business strategy.

1. Source: UK Green Building Council.
2. Source: UK government press release - Rigorous new targets for
green building revolution (January 2021).

man drawing on a map

The carbon cost of building a home

An average Gleeson home takes 47 tonnes of CO2e to build – this will rise to 54 tonnes under the Future Homes Standard due to the increase in size of properties, thermal insulation and increased embodied carbon of alternative heating systems. The average Gleeson home adds 107 tonnes of CO2e of in-use emissions over 60 years. However the installation of air source heat pumps and the decarbonisation of the grid will reduce in-use emissions to 40 tonnes of CO2e over 60 years.

Carbon cost of building a home

Reducing our emissions

We take our responsibility for minimising our impact on the environment very seriously, and are continually looking at ways to improve the efficiency of our homes in use, and to reduce the embodied carbon of the materials we use to build them. During the year, we launched new policies on efficient generator use and the procurement and use of biodiesel. Turning these policies into actions will help further reduce our carbon emissions. In addition we are continuing to make progress on the initiatives commenced in prior years.



Our Progress

Our scope 1 and 2 emissions increased to 2.09 tonnes CO2e per home sold, missing our target of 1.75 tonnes CO2e in 2023, which was set in 2021. This was due to a number of factors including the way in which we measure intensity  based on homes sold rather than homes built meaning the emissions generated in build activities were not matched by the number of homes sold. As well as this, a number of factors led to an increase in generators being used on site for longer, rather than sites being connected to the National Grid. This increased our diesel usage on site during the year.

It remains a key priority to reduce scope 1 and 2 emissions and our commitment to Science Based Targets will set out an absolute reduction target for scope 1 and 2 emissions.

In-use emissions

Whilst the carbon emissions from housebuilding are clearly significant at 47 tonnes per home sold, the emissions from our homes in use over 60 years contributes a further 107 tonnes of carbon emissions. We are looking at ways to reduce the in-use emissions for our customers through heating and energy efficiency.

The Future Homes Standard is designed to reduce the emissions over the lifetime of the house and this is being implemented by changes in building regulations. One significant change is the move away from gas-fired boilers in homes. Alternative technologies are being widely taken up and one of the most efficient is air source heat pumps. Our projections suggest that the Future Homes Standard will increase embodied emissions of building a home by 9 tonnes through the requirement of more materials however this is expected to reduce in-use emissions over the 60 year period by 69 tonnes saving an overall total of 60 tonnes. This assumes that there will be a wider decarbonisation of the electricity grid as the UK switches to more renewable energy sources.


We installed our first ASHP in a detached home on Erin Court, Derbyshire, in September 2021. In partnership with Sheffield Hallam University we ran a number of tests, including assessing the efficiency and running costs. These test results showed an impressive efficiency of 293% compared to the 94% efficiency of a gas boiler.

Since this initial test we have continued to work with Sheffield Hallam University and our ASHP manufacturer to make changes, and further testing is now under way to provide a better understanding on the effects of seasonality on ASHP efficiency.

As these continue, we have taken the decision to move from traditional gas boilers to ASHP technology. We are already installing ASHPs on certain developments and all Gleeson homes starting build post June 2023 will be heated using air source heat pump technology. 

Energy efficiency

We build high-quality, affordable homes that are energy efficient. 95% of our homes achieve an energy performance rating (“EPC”) of B or above compared to the house building industry average of 85%.

When compared to existing dwellings, a Gleeson home produces 48% lower carbon emissions due to its higher energy efficiency.

This allows us to play our part in helping our customers live sustainable lifestyles in their new homes, saving on average £700 per year against the energy costs of an existing dwelling.

Energy bills: Average electricity and gas usage using energy prices per August 2022. Gleeson Homes based on actual usage data provided by British Gas. Existing dwelling based on “Great Homes” website using data from the National Energy Efficiency Database (gov.uk).

Scope 1 and 2 Emissions target to reduce to 2.09

of Homes achieving an 
EPC rating of B

of waste diverted
from landfill

of timber from FSC or PEFC
certified sources

woman walking a dog along modal walk in Derbyshire

Case study

Regenerating land - Model Walk
Worksop, Derbyshire

coal mine

Model Walk near Worksop sits on part of the former Creswell Colliery, which was in operation from 1894 until its closure in 1991. The site has an extensive history and, following its closure, the land remained derelict and disused for around 25 years until it was acquired by Gleeson Homes.

man in protective clothing

Since its closure, all of the old mining buildings were removed by the former owners, but the site had extensive rubble, hard standing and detritus across it. In addition, parts of the site were contaminated from the former activities including the presence of polycyclic aromatic hydrocarbons, arsenic and naphthalene together with areas that were infested with Japanese knotweed.

regenerated land

A detailed planning application was submitted by Gleeson Homes in 2016. Following years of neglect and anti-social behaviour on the land, the scheme received unanimous support.

The site required extensive remediation including the removal of hardstanding, brick, glass, contaminated topsoil, Japanese knotweed and other contaminants. There were also varying capping depths required across the site and additional radon precautions in certain areas.

row of new houses

The site has 197 plots with two, three and four-bed homes and open space. Special designs were needed for the homes fronting on to the historic Model Village conservation area to address and celebrate a unique setting. The development has also paved the way for the regeneration of the remainder of the former colliery to the south and west, providing high quality, affordable homes for local people.

drone view of housing neighbourhood

Case study

Regenerating land - Carlisle Park
Rotherham, South Yorkshire

Old factory

This site in Kilnhurst, South Yorkshire, had operated as a chemical works for over 100 years.

It has acted as a bitumen processing plant, tar distillery, iron works and a forge. The site had been derelict for five years before Gleeson acquired it for development in 2012.

Mud pit with pollution

There were three major challenges to the development of the site:

• The land was heavily contaminated with non-aqueous phase liquids (“NAPL”) of petroleum carbons, solvents including phenols, and other less mobile polycyclic aromatic hydrocarbons.

• There were numerous un-surveyed foundations and obstructions from the former chemical works.

• It was unclear what services were passing below the site as the buried services for water, gas and electric were not clearly set out.

Sealing the land

Gleeson has spent £8.6m remediating the site over the period of development including:

• 300,000m3 of contaminated ground was excavated, treated and stabilised.
• 25,000m3 of derelict foundation concrete was broken out, crushed, processed and reused.
• A proprietary geosynthetic clay layer, incorporating a bentonite clay layer, was placed over the whole site.
• The site was then capped with a 1.7 meter thick layer of clean material placed as a foundation above the capping layer.

New house on site

As a result of the remediation we:

• Cleaned the site.
• Stabilised the contamination.
• Reused all the stabilised materials on site.
• Exported and recycled for scrap the waste metals from the structure of the chemical works.

All works were supervised by third-party consultants and approved by both the regulators of Rotherham Borough Council and the Environment Agency.

Carbon Reduction Initiatives

Air source heat pumps - For all homes built after 15 June 2023, we are installing Air Source Heat Pumps (“ASHPs”), which means that our homes will be net zero ready in preparation for the UK grid being fully decarbonised by 2035, or where our customers move to a verifiable “green tariff” with their energy supplier.

Concrete bricks - Over the past few years we have
increased the use of concrete bricks, which provide
a significant reduction in embodied carbon over a
traditional clay brick. In 2023 we sold over 200 homes
built using concrete bricks or reconstituted stone. This
will continue to increase and, as with any other material
changes, we will ensure that these do not impact on the
quality, longevity and aesthetics of the homes we build.

HVO fuel – As part of our scope 1 emissions reduction initiatives, we are using hydrotreated vegetable oil (“HVO”), which provides a significant carbon saving over regular “white” diesel. However, the demand for HVO and the impact of the energy and fuel crisis this year has resulted in the cost of HVO soaring to the point where it became commercially unviable on certain sites. As a result, HVO accounted for 7% of total liquid fuels that we used on site. We are continuing to monitor fuel costs and our fuel policy has been updated to favour HVO over white diesel where it is commercially viable.

Supply chain and sustainable materials – In 2022 we proudly became a partner of The Supply Chain Sustainability School. This enables us to upskill colleagues and work collaboratively with other housebuilders, subcontractors and suppliers within the construction industry to achieve common goals in delivering a sustainable future. Throughout the year we have provided learning pathways for colleagues and subcontractors and have achieved the Gold level of engagement.

Hybrid generators and grid connection – One of the largest opportunities within our scope 1 and 2 reduction initiatives is gaining early grid connections for our developments and limiting the use of generators on site. Our electricity is purchased on REGO-backed green tariffs. Combined with the UK Government’s commitment to decarbonise the grid by 2035, energy transition from burnt fuels using generators to “mains” electricity provides significant carbon emissions savings. As part of our processes, we target getting sites connected to the grid at the earliest opportunity. Where generators are required, we have undertaken trials this year using hybrid generator technology. Trials of the 30 kVA generators showed average fuel and emissions savings of 39% over a standard diesel generator. As such, all new sites will utilise hybrid generators until a connection to the grid is achieved, where it is commercially viable to do so.

Natural resources

Our developments are typically located in areas where there is a need for regeneration including areas of deprivation or brownfield sites that would otherwise remain unused. Four out of five of our homes sold are in the most deprived areas of the country or on brownfield land. We invest in our sites, creating attractive and well-planned developments with open space and access to local facilities. We continue to purchase land in areas that are in need of regeneration, but with good transport links and access to local facilities and employment. Page 69 sets out an example of the brownfield land remediation that we undertake.

We recognise that water is a valuable resource. Last year we committed to developing a water strategy. This is in progress and we are targeting to complete this within the next 12 months. This water strategy will address our water demand and aim to reduce our reliance on licenced water supply. As part of our strategy we will be evaluating the feasibility of incorporating grey water usage into our operating activities and will explore initiatives such as rainwater harvesting and the use of surface water during construction for site processes such as dust suppression. Our strategy will also include improved methods of tracking water consumption across the business with actual usage data, rather than estimates. The strategy will also focus on climate-related water risk to the business.

Water consumption 2023 2022
Cubic metres of water consumed 83,651 90,692
Cubic metres of water consumed per home built 49 45
Cubic metres of water consumed per site 984 1,093

All of our homes are fitted with dual flush toilets, low flow taps and showers and water meters. They are designed to achieve an internal water use of less than 110 litres per person per day (actual usage is nearer 104 litres per person per day). This is 12% lower than the maximum allowance specified by building regulations. We are going further and our newest home designs will use around 97 litres per person per day through higher specification sanitaryware. This provides 22% less consumption than the current maximum allowance.

During the year, we launched new policies on sustainable procurement and sustainable packaging to ensure that we are reducing our impact on natural resources.

As part of this:

  • We source 99.9% of the timber we use in construction from FSC or PEFC certified sources;
  • We are engaging with suppliers to use packaging materials that are recyclable or biodegradable where possible; and
  • We will be examining alternative materials to those currently used, where these have lower embodied carbon emissions can be more easily recycled or reused; and
  • We have partnered with the Supply Chain Sustainability School. This provides us with the opportunity to upskill and actively engage with our supply chain and our own staff. The platform enables us to collaborate with our industry peers to achieve common goals delivering a sustainable future.


In the year, we diverted 99.0% (2022: 99.0%) of waste generated away from landfill through recycling or conversion to energy. We continued with our target of zero waste to landfill and we will achieve this by engaging with specialist waste management providers and implementing initiatives such as pallet repatriation, re-use of waste materials on site and engaging with our upstream supply chain to minimise incoming waste such as packaging. This year will see the development of targeted, role-specific training and awareness with learning pathways including waste management practices.

During the year, our total waste amounted to 11,391 tonnes (2022: 12,272), a waste intensity of 6.6 tonnes (2022: 6.1) per home sold. Absolute waste has decreased by 7.2%, but due to the decrease in homes sold, our waste intensity has increased. Measures taken on sustainable procurement, packaging and waste management helped to reduce the absolute waste produced in the year. We continue to work with our supply chain and internal stakeholders to firstly reduce waste generated, then to maximise waste recovery options. Hazardous waste is generally limited to packaging containing hazardous residues such as paint tins, aerosol canisters, sealant and adhesive cartridges.

After November 2023, developments will be required (via the Environment Act 2021) to create a measurable 10% gain to biodiversity, either via habitat retention, enhancement or creation on site, or by the funding of habitat creation offsite, and then also safeguard it for at least 30 years. This is referred to as Biodiversity Net Gain (“BNG”). When we acquire land for development, these sites are often brownfield, including land contamination with non-native, invasive plant species present. The land has often been left for many years to naturally colonise and rewild, so can sometimes have a high biodiversity baseline. Clearing land for remediation in readiness for construction can have an initial short-term detrimental impact on nature at the site but provide a long term benefit and legacy.

We consider biodiversity on our developments from the design stage, considering each site individually to try to retain valuable habitats as well as considering our impacts on protected species and habitats in the surrounding area.

Through planning regulation and our own enhancements we leave a net gain to biodiversity and manage any protected species, which have either been identified during ecological surveys at pre-planning stage or during construction.

We work with local residents, specialists and local councils to ensure we are properly considering the needs of the community and the environment. We hold public consultations or attend parish or other local events to understand the views of local people and we strive to take these into account in developing sustainable and sensitive planning applications. We work very closely with specialist ecology consultants to ensure we are being respectful of the environment including local wildlife, water needs, carbon emissions and more.