Southwest Environmental Limited

Exeter Sunlight & Daylight Assessments

Are you planning a development in Exeter, East Devon, or Mid Devon? At Southwest Environmental Limited, our Exeter office provides accurate Sunlight & Daylight Assessments. Utilizing 3D modelling, we evaluate compliance against Building Research Establishment standards (BRE 209: Site Layout Planning for Daylight and Sunlight).

Our assessments address two key planning considerations:

1. Impact on Existing Neighboring Buildings

For infill developments and urban extensions, planning officers assess whether proposed buildings will unacceptably shade surrounding properties. A Daylight Impact Assessment quantifies potential changes to neighboring windows:

• Vertical Sky Component (VSC): Measures available skylight on vertical window surfaces, targeting levels of 27% or higher.
• Annual Probable Sunlight Hours (APSH): Evaluates direct sunlight availability to neighboring windows year-round and during winter months.
• Overshadowing to Outdoor Spaces: Ensures amenity spaces retain at least two hours of sunlight across 50% of their area on March 21st.

2. Internal Daylight Adequacy in Proposed Schemes

To ensure healthy interior environments, local policies require verification of internal light levels for new occupants. We perform Internal Daylight Assessments using daylight factor calculations and climate-based modelling:

• Average Daylight Factor (ADF) & Target Illuminance: Verifies internal illuminance compliance for living areas, bedrooms, and kitchens.
• Spatial Daylight Autonomy (sDA): Evaluates how efficiently natural light penetrates primary room spaces over the year.
• Solar Gain & Overheating Balance: Aligns daylight entry with climate resilience goals to minimize summer overheating risks.

Why Choose Our Exeter Team?

Based at Kings Wharf on Exeter Quay, we combine local site knowledge with technical 3D modelling to deliver clear compliance reports for Exeter City Council and surrounding Devon LPAs.

Contact our Exeter Office today on 01392 927 961 or email exeter@southwest-environmental.co.uk to discuss your Sunlight and Daylight modelling requirements.

Example Projects & Insights

Below are related insights and technical project summaries from our weblog:

• Net Zero Building Policies: Balancing natural sunlight and solar gain to optimize energy performance in new housing developments.
• Daylight Impact Assessment for Urban Infill: Proving VSC compliance for multi-story residential infill schemes.
• Light Pollution & Glare Mitigation: Evaluating reflected solar glare and facade design to protect surrounding highway safety.
• Internal Daylight Modelling for Conversions: Achieving ADF targets within constrained historic structures.

What Our Exeter Clients Say