How to get a net zero building

Whether you’re in the exciting position of creating a new building, or adapting an existing one, there are plenty of ways to make it greener, says Mark Brown

Working towards net zero involves both reducing the amount of energy used in a building’s construction and in its day-to-day operation (through heating and cooling systems, cooking, lighting and plug loads).

In 2020, the Government issued the following guidelines:

Building construction:

  •  Natural, sustainable materials should be prioritised
  •  Efforts should be made to use fewer materials generally
  •  Transportation to the build site should be reduced by utilising off-site construction
  •  Waste and site works should be minimised.

Operational energy:

  •  Glazing should have high U values and, where possible, a low surface area, balancing the need for natural daylight and thermal comfort. All windows should be openable to allow cross ventilation
  •  All systems for heating, cooling, pumping and fans should include demand controls
  •  Fossil-fuelled heating and hot water systems must be avoided and renewable energy sources maximised.


A net zero classroom block at Samuel Ryder Academy, St Albans

Since the small (250-pupil) Samuel Ryder secondary school expanded to become an all-through school for pupils aged 4 to 19, demand for places has outstripped capacity. As a result, the local authority provided further funding to extend the school’s provision. Using sustainable materials, contractor TG Escapes completed a new block in 2020, consisting of seven English classrooms, English and SLT offices, Year 7 and 8 toilets, a media suite and two Year 6 classrooms. Price was one of the key criteria, but certainly not the only one, says deputy headteacher Ian Bailey.

‘Energy efficiency was considered very important, given the passion of many pupils for environmental issues. Rightly so – it’s this world that they are going to inherit.

‘The students and staff find their time in the building wonderful. We are also looking forward to the children being able to track and talk to the trees that were gifted to the school as part of TG Escapes’ tree-planting initiative.’

With an A+ energy performance certificate, the new block is carbon neutral (net zero) in operation. M&E consultants Designphase achieved this in four ways:

Active Ventilation: A quiet and energy-efficient Passivent system draws in and circulates fresh air and removes stale polluted air.

Lighting: A combination of high-efficiency LED lighting was selected for different spaces across the building. Sensors and programmable controls minimise energy use. Daylight dimming means lights dim automatically on days with plenty of natural light.

Solar Energy: A large 72kW solar photovoltaic system was installed on the roof by Solar for Schools. It should generate around 65,000kWh of clean electricity a year, stopping 25 tonnes of CO2 being produced. During its lifetime, the installation should stop 560 tonnes of CO2 from being released into the atmosphere, and also cut the school’s electricity bills as they’ll buy less from the grid.

Air Source Heat Pumps: These produce between 3-4 kilowatts of heat for every kilowatt of electricity used. The system tempers the incoming air with the extracted hot air using low wattage fans to create a comfortable environment. The system also moves energy to where it’s needed in the building, reducing electricity input by up to 30%. It also heats water.

  • Mark Brown is a consultant for TG Escapes Eco-Buildings, which aims to create buildings which are affordable, energy efficient and enhance the well-being of their occupants.



‘We conducted an energy audit last year and have changed our lighting to LED, installed double glazing and updated our boiler. These are three main areas we are now able to control. We also have zoned thermostats, which can trigger certain parts of the school system to come on as needed, for example for an after-school club. We were able to fund some of this work through grants.

We’ve introduced a ‘switch off light’ campaign. School councillors have a duty during break, lunch and teachers’ PPA time to make sure that lights and whiteboards are off. Our children are taught about the environment and sustainability from many angles. For instance, our local egg farmer has solar panels on their fields and they come and speak to the children, We have the Level 3 (top level) Solihull Greener Schools Award and a Silver Green Flag Award.’

Howard Rose, lead for sponsorship and publicity, Balsall Common Primary School, Solihull (710 pupils)



‘We are an eco-friendly school with a commitment to efficient energy use, promoting sustainable transport and the preservation of wildlife. We have achieved Gold School Travel Plan status, and have a sustainable curriculum. We made a bug hotel for our playground and have reduced plastic use with a ‘no plastic, you’re fantastic’ lunchtime incentive. We also recycle batteries and school uniform, and organise bike-ability and scooter safety workshops.

In 2020, Lewisham Council provided funding for RAFT (Retrofit Action for Tomorrow) to deliver a programme of education and a zero carbon retrofit action plan for our school. RAFT is a local not-for-profit project and its founder, Harry Paticas, led the school through the options of how to make changes.

Harry developed an impressive proposal for the school buildings to become zero carbon in four years and across all areas by 2030. The plan included the creation of green areas and roof gardens, twice as many solar panels, the removal of our boiler and retrofitting the building. Now we need to find the £3.5m of funding! If the government wants society to be zero carbon, it has to do something about it. This is about the future of our planet. There are possibilities to put things right and we all have a part to play. As a faith school, we also have a duty of stewardship to protect our beautiful world.’

Margaret Hanrahan, former headteacher, St Winifred’s Roman Catholic Primary School, Lewisham (421 pupils)


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