Designing a nett zero carbon rated building

  • Zero carbon building design is a gradual, strategic process focused on energy savings, practical end-user functionality and stunning features.

    Robert Whetham Associates are Mechanical & Electrical Design Consultants. We collaborate with contractors on a range of projects across many sectors, with increasing focus on nett zero carbon rated building projects.

    What is the process in designing a nett zero carbon rated building?

    We begin with design measures to reduce the energy consumption, and therefore carbon emissions.

    Passive design measures

    There are several passive design measures that can be implemented to reduce energy consumption.

    Building fabric improvement

    This involves the improvement of U-values which is the rate of transfer of heat through a structure. Measured in W/m²K, the lower the U-value, the better insulated the structure is.


    Designing a nett zero carbon rated building

    Daylighting strategy

    Maximising daylighting levels with full height glazing reduces the need for artificial lighting during daylight hours.

    Solar shading

    Solar shading with devices such as Brise Soleil, deflects direct sunlight and significantly reduces heat gain through large glass doors and windows, thereby reducing the need for air conditioning systems.


    We facilitate natural ventilation by installing windows that can be easily opened, reducing the need for mechanical ventilation which consumes energy.

    Other passive design measures

    As well as the core measures above, to reduce energy consumption we would also consider:

    – The site location
    – Site weather
    – Any microclimate
    – Building layout
    – Building orientation – positioning against seasonal variations such as the sun’s path or prevailing winds
    – Building occupancy type


    Designing a nett zero carbon rated building

    Baseline Model

    From the passive design exercise, we derive a baseline model. This will typically include a gas fired boiler or other heating source.

    The baseline model is a clearly defined project plan and fixed reference point to measure a project’s progress. It will include passive design measures and the proposed servicing strategy, but without any low zero carbon (LZC) technology incorporated.

    Estimated baseline energy demand

    An estimated baseline energy demand, energy cost, and regulated greenhouse gas (GHG) carbon dioxide equivalent (CO2e) emissions will be calculated for the proposed building from the baseline modelling exercise.

    The potential impact of LZC technologies

    The next stage is to evaluate the energy and cost impact of potentially suitable LZC technologies against the baseline model. Typically, the possible LZC technologies to be considered and evaluated would be:

    – District heating from a centralised location through a system of insulated pipes
    – Combined heating and power (CHP) plant where the heat boils water to make steam, which drives a power source (maybe a turbine) to make a generator create electricity
    – Solar photovoltaic panels (PV)
    – Solar thermal hot water
    – Wind turbines
    – Biomass boilers
    – Air source heat pumps
    – Ground source heat pumps
    – Water source heat pumps
    – Hydropower

    The impact of incorporating the chosen LZC technologies, and the savings they create against the baseline model, are then assessed. Recommendations are made based on the results of the assessment, which are then incorporated into the design.

    Robert Whetham, Managing Director Comments.

    “We undertake a range of mechanical and electrical design projects spanning Education, Healthcare, Industrial and Commercial and the Emergency Services. We are currently undertaking a number of zero carbon building projects, for example Crewe Fire Station.”


    Designing a nett zero carbon rated building

    The result of the process

    The end result of the above process is energy efficient buildings. Nett zero carbon building design is a complex process, but the mandate for energy efficiency is clear.

    Net carbon zero consulting for building design require strategic planning and an eye for appealing design. The key is to find the sweet spot of outstanding energy efficiency and impressive end-user benefits.

    Can we help?

    For expert help or advice in constructing a nett zero carbon building, please get in touch with the team at Robert Whetham Associates. We design building services for new build nett zero carbon buildings, and facilitate a reduction in the carbon emissions of existing buildings.


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