Daylight and Sunlight Assessments
MACH provides expert Daylight and Sunlight Assessments to support planning applications throughout the UK. Whether designing a new development or preparing a planning submission, our BRE 209-compliant reports ensure your scheme meets local authority requirements for natural light. We deliver fast, accurate, and cost-effective assessments that evaluate internal daylight levels, sunlight access, and potential impacts on neighbouring properties. Our goal is to help you secure planning approval while optimising your design for high-quality natural light and minimal environmental impact.
What is a Daylight and Sunlight Assessment?
A Daylight and Sunlight Assessment is a technical study that examines:
- Daylight levels within proposed buildings
- Sunlight access for key living spaces
- Overshadowing impacts on neighbouring homes and outdoor amenity spaces
Depending on your project needs, MACH provides reports following the latest BRE Guidelines (BRE 209: Site Layout Planning for Daylight and Sunlight) that help demonstrate compliance with planning policies from local councils across the UK.
Internal Daylight Assessment Report
An Internal Daylight Assessment measures how much natural light reaches habitable rooms within a proposed building. We use specialist daylight modelling software to assess daylight levels primarily through the Daylight Factor method.
Key factors considered in assessments include:
- Window location/size and the visible light transmittance (VLT) of glazing
- Floor area, ceiling heights, room layouts and reflectance of internal surfaces
- External obstructions such as nearby buildings, balconies, or overhangs
Where required, we can also provide a Sunlight Assessment for main living spaces using Annual Probable Sunlight Hours (APSH). MACH delivers clear, compliant reports that demonstrate adherence to BRE guidelines and local authority requirements.
If daylight is insufficient, we offer practical advice on design improvements, such as changes to glazing, rooflights, or sun tubes, or altering room layouts to meet daylight standards.
Daylight and Sunlight Impact Assessment Report
Where your proposed development may affect neighbouring buildings or amenity spaces, a Daylight and Sunlight Impact Assessment is essential for your planning application.
Our assessments cover:
- Loss of daylight to adjacent windows, measured using the Vertical Sky Component (VSC)
- Loss of direct sunlight to windows and outdoor amenity areas measured by Annual Probable Sunlight Hours (APSH)
- Loss of daylight distribution to internal areas, measured via a No Sky Line assessment.
MACH’s clear, visual reports effectively communicate your scheme’s impact and demonstrate that you’ve thoroughly considered neighbours’ access to natural light, ensuring full compliance with BRE 209 guidance.
We also provide professional advice to help optimise your scheme’s design—maximising massing while minimising impacts—to support a successful planning approval.
Why Choose MACH for Your Daylight and Sunlight Assessment?
At MACH, we don’t just focus on daylight and sunlight in isolation — we take a holistic approach that considers how natural light interacts with other key performance factors like thermal comfort, energy efficiency, and acoustics constraints. Our goal is to help you identify the ‘sweet spot’ where your building performs at its best.
We support projects of all scales but particularly excel on challenging urban or constrained sites, where daylight access is limited and thoughtful design is essential.
Our skilled staff are able to provide quick and detailed daylight and sunlight assessments with a pragmatic approach, offering advice on how to improve your design when needed.
Our team of friendly engineers are more than happy to answer any questions you have about your project.
FAQ
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Most new-build residential or mixed-use developments in dense urban areas with limited access to daylight, particularly basement schemes, will require an internal daylight assessment as part of the planning process.
In addition, large developments such as high-rise residential blocks, office towers, or retail complexes located near existing residential areas typically require a daylight and sunlight impact assessment. This helps demonstrate that your proposal will not significantly reduce daylight or sunlight levels of neighbouring properties.
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The daylight and sunlight assessment should be carried out early in the design phase of your building project, ideally before detailed design work begins. This allows time to make any necessary adjustments to ensure compliance with BRE 209 guidelines and avoid costly delays later in the process. MACH always recommend carrying out the assessment before carrying out a planning application, as the results of the assessment could change the design of your building.
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The time required for a daylight and sunlight assessment can vary depending on the complexity of the project. For standard developments, the process typically takes 5 – 15 working days. More complex projects may take longer, particularly if multiple revisions are needed.
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The cost of a daylight and sunlight assessment depends on the size, scale and complexity of the development and surrounding context. Get in touch so MACH can provide a tailored quote based on your specific project needs.
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To ensure an accurate and thorough assessment, we require the following information:
- Site plan
- Floor plans
- Elevations
- Sections
- Visible light transmittance (VLT) of proposed glazing
- Details of internal surface finishings (reflectance value if known)
- Site photos
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If your building fails to comply with BRE 209 daylight and sunlight guidelines, MACH will work with you to explore practical mitigation strategies that optimise internal daylight levels and minimise the impact on neighbouring properties. We will guide you through the necessary changes to ensure compliance while maintaining building efficiency and comfort, also consider cost and build practicalities.
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MACH's Other Services
MACH is a multi-discipline company, where we are able to provide a one-stop-shop for your planning requirements for projects of any size.
With team members trained across various disciplines, our services are provided in a holistic manner with each deliverable carried out in tandem with the other, ensuring there are no gaps in communication or delays in the design process.
Integrated design creates more opportunity for low carbon passive design through avoiding the need for mechanical cooling or restrictive thermal requirements on the façade, which can lead to significant cost savings as well.
Our services include:
