The BRE 2022 daylight provision tests are the new way internal daylight is judged in UK planning applications, and they replace the long-standing Average Daylight Factor (ADF) calculation with target illuminance and spatial daylight autonomy measures. If you have designed schemes against the old ADF figures, the headline change is simple: the metric you used to quote is gone, and assessors now ask whether rooms receive enough lux for enough hours of the year.
This matters because most local planning authorities across England and Wales now expect daylight and sunlight reports to follow the third edition of Site layout planning for daylight and sunlight: a guide to good practice (BR 209), published by the BRE in June 2022. Getting the method wrong, or assessing against superseded targets, can undermine an otherwise sound application. Below we explain what the new tests are, how they work, and what they mean for the rooms in your scheme.
What the BRE 2022 daylight provision tests actually measure
The 2011 second edition of BR 209 assessed daylight inside new dwellings primarily through ADF — a single percentage that compared internal illuminance to the available external light. The 2022 edition aligns the guidance with BS EN 17037 “Daylight in Buildings” and deletes the old ADF test for new development. In its place sits the concept of daylight provision, which can be demonstrated in one of two ways.
The first and preferred route is a target illuminance assessment using climate-based daylight modelling. A room is considered to provide adequate daylight where it achieves at least 300 lux across 50% of the reference plane, and at least 100 lux across 95% of the reference plane, for more than half of the daylight hours in the year (around 2,190 hours). The reference plane is set at a working-plane height inside each room. This is closely related to spatial daylight autonomy (sDA), which describes the proportion of a space meeting a lux threshold for a set proportion of occupied hours.
The second route uses median daylight factor targets. Because full climate-based modelling is not always proportionate, BR 209 provides equivalent daylight factor figures that approximate the illuminance targets for the UK climate. These vary by room type, broadly mirroring the older ADF thresholds — bedrooms at the lowest provision, then living rooms, with kitchens expected to achieve the most. Assessors can use whichever method suits the scheme, provided it is applied consistently and reported transparently.
Why the change from ADF to illuminance matters
The shift is not merely cosmetic. ADF rewarded the ratio of glazing to room area and skylight availability, but it said little about how light is distributed across a room or how it varies through the year. Target illuminance and sDA are time-based and spatial: they ask how much of the room is usefully lit, and for how long. A deep room with a generous window may post a respectable ADF yet fail the new 50%-at-300-lux test because the rear of the room sits in relative gloom for much of the day.
For designers, three practical consequences follow:
- Room depth is under more scrutiny. Long, narrow rooms lit from one end are harder to satisfy, so open-plan layouts and dual aspects help.
- Glazing position counts, not just glazing area. Head height, sill height and the unobstructed view of sky all influence the result.
- Climate-based modelling is becoming the norm. Where the median daylight factor route is borderline, an illuminance assessment using UK climate data often gives a fairer, and sometimes more favourable, picture.
It is worth stressing that BR 209 remains guidance, not statute. It is advisory, and its targets are intended to be applied flexibly with regard to context. Town-centre and high-density sites, in particular, may justify departures from the numerical targets where the planning balance supports the scheme. The National Planning Policy Framework encourages efficient use of land, and many authorities accept that strict suburban daylight targets cannot always be met in urban settings.
What stayed the same in BR 209 (2022)
Not everything changed. The tests used to assess the impact of a proposed development on neighbouring properties are largely unchanged. Loss of daylight to existing windows is still checked using Vertical Sky Component (VSC) and the no-sky-line / daylight distribution test, while loss of sunlight is assessed using the Annual Probable Sunlight Hours (APSH) method. So if your concern is overshadowing a neighbour rather than internal provision in your own new flats, the familiar VSC and APSH figures still apply.
This split is a common source of confusion. The deleted ADF test relates to daylight within new accommodation; the retained VSC and APSH tests relate to amenity impacts on existing surroundings. A complete daylight and sunlight report for a planning application typically addresses both, and it should be clear which standard each section follows.
Overshadowing and amenity space
Alongside internal provision, BR 209 retains the sunlight-on-ground and overshadowing assessment for gardens and amenity areas, centred on the 21 March equinox test. At least half of an amenity area should receive at least two hours of sunlight on 21 March for it to be considered well sunlit. The 2022 edition refines some of the supporting advice, but the principle is consistent with earlier guidance, so existing schemes assessed on this basis do not need wholesale rework.
Preparing a scheme that passes first time
The most reliable way to avoid daylight objections is to model early, before the layout is fixed. Once internal partitions, window heights and the massing of neighbouring blocks are locked in, options narrow quickly. We recommend a short pre-application daylight study at concept stage so the architect can test room depths and glazing strategies against the BRE 2022 daylight provision targets while changes are still cheap to make.
If a scheme is borderline, sensible mitigation includes increasing window head height, reducing room depth, introducing dual aspect, specifying higher light-transmittance glazing, and lightening internal surface finishes. Where targets genuinely cannot be met on a constrained urban site, a well-argued report that explains the context and the planning balance is often more persuasive than chasing numbers that the site cannot support. If you are researching local expectations, our area guides such as daylight requirements in Cambridge set out how individual authorities tend to approach these assessments.
How Fortress Associates can help
Fortress Associates prepares daylight and sunlight reports to the BRE 2022 (BR 209) and BS EN 17037 standards for planning applications right across the UK. We assess internal daylight provision using target illuminance and spatial daylight autonomy, check neighbour impacts with VSC and APSH, and produce clear, planner-ready documents. Most reports are delivered within four to five working days, and we ask for no advance payment. To discuss a scheme or request a quote, see our services page or get in touch with the details of your site and drawings.
Sources & further reading
Need help with a UK planning project?
Fixed-fee daylight reports and Building Regulations drawings — delivered in 4–5 working days. No advance payment.
Request a free quote