Operational Energy

The World Green Building Council set out in a 2019 report that by 2050 all existing building stock must be net zero operational carbon. To achieve this a number of strategies should be adopted if we are to limit existing buildings’ carbon emissions:

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Passive House/Enerphit

In 2020 Material Works Architecture became certified Passive House Designers. Passive House is a building standard developed in Germany in the 1990s that is being increasingly adopted as the gold standard for low energy building design. To achieve Passive House certification a building needs to meet a series of criteria demonstrating minimal energy consumption way below typical building practices. It is estimated that 27% of all global carbon emissions come from the running operation of buildings (heating, cooling and lighting). Passive house demonstrates a method whereby this can be reduced to zero, offering a powerful tool to tackle climate change.

The standard focuses on reducing heat-loss to such an extent that real advantage can be made of passive heat sources such as solar gain through glazing and the heat given off by a building’s occupants.  This is measured through a series of calculations that take into account the thermal performance of the buildings materials, heating and ventilation systems, the location and orientation of the building and the expected passive thermal gains throughout the year.

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Upgrading Existing Fabric

If the thermal performance of the existing fabric is inadequate, this should be improved where possible and sensitive to the existing. Insulating internally should be considered against the existing composition of the external walls and a breathable solution provided to prevent mould and damp damage. Draught proofing and additional shading can help to improve the thermal comfort of a building in operation. These methods will help to reduce the amount of energy loss in operation and reduce overall cost of bills. 

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On Site Renewables

The embodied carbon of a building’s operational consumption can also be reduced by installing on-site renewables to generate energy. Roof space can be used to harness solar power and power electrical whilst air source heat pumps provide an efficient method of heating and cooling spaces, these methods often have cost incentives from the government or with energy suppliers. An Energy Strategy often helps to understand impact of layout on proposed cooling and heating systems. 

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Efficient Services

Proposed services should be designed to achieve maximum efficiency and reduce energy consumption. All lighting should be low energy LED and controlled by motion sensors to consider occupation as per demand. Smart lighting systems allow for colour balance to be adjusted throughout the days and months to reduce unnecessary power usage. Designs should also maximise the use of existing natural light sources to avoid further additional lighting. 

Similarly, seasonal commissioning will ensure that any systems are operating at maximum efficiency levels throughout the year and according to different levels of occupation. All new equipment and appliances should conform to an EU energy label A+. 

^ Hackney Lofts achieved near Passivhaus standards as a retrofit, with significant improvements made to the external fabric of the building. (Fred Howarth, 2023). 

^ Stoke Newington Residential Extension - the existing fabric of the rear outrigger was upgraded with wood fibre insulation and timber construction to achieve high thermal performance and reduce energy consumption.