Daylight in buildings according to EN 17037

Key facts in brief: EN 17037 (current German edition 2022-05) assesses daylight using four criteria: daylight provision, view out, sunlight exposure and glare protection. For daylight provision there are three recommended levels: minimum (300 lx on 50 % of the area), medium (500 lx) and high (750 lx), each for at least half of the daylight hours.

What the standard covers

EN 17037 sets out principles for an adequate subjective impression of brightness from daylight and an adequate view out, and contains recommendations on the duration of sunlight exposure in occupied rooms. The German 2022-05 edition replaces the 2019 version ^[1]. The standard distinguishes three levels – minimum, medium and high; the minimum recommended level should be stated ^[1].

Daylight provision: the three levels

For daylight openings in vertical and inclined surfaces ^[2]:

Level	Target E_T on 50 % of the area	Minimum target E_TM on 95 % of the area	Share of daylight hours
Minimum	300 lx	100 lx	50 %
Medium	500 lx	300 lx	50 %
High	750 lx	500 lx	50 %

A level is achieved when both conditions are met simultaneously ^[2]. Proof is provided by calculation, either using climate data for the location or, in simplified form, via the daylight factor.

Important for planners: The standard does not prescribe which use requires which level ^[2]. The level must therefore be agreed with the client and recorded in the contract.

The other criteria

View out: assesses viewing angle, viewing distance and the number of visible layers (sky, landscape/buildings, ground).
Sunlight exposure: recommendation on how long an occupied room should receive direct sunlight on a reference day – relevant for homes, hospital rooms and nurseries, for example.
Glare protection: protection against glare from the sun and sky, usually via solar and glare protection systems.

Level	View: horizontal sight angle / outside distance / layers	Sunlight exposure on the reference day	Glare protection (DGP, exceeded for max. 5 % of usage time)
Minimum	≥ 14° / ≥ 6 m / 1	≥ 1.5 h	0,45
Medium	≥ 28° / ≥ 20 m / 2	≥ 3 h	0,40
High	≥ 54° / ≥ 50 m / 3	≥ 4 h	0,35

Compiled from ^[2] ^[3]; the view criteria each apply to at least 75 % of the used floor area ^[2].

The reference day for sunlight exposure can be chosen between 1 February and 21 March; the reference point is at least 1.2 m above the floor and 0.3 m above the window sill ^[2]. Since DIN 5034-1 was withdrawn, LiTG recommends the "minimum" level as the minimum requirement for sunlight exposure, and the "medium" level of 3 hours for living rooms, children's rooms and day-care centres ^[4]. Glare is assessed using the daylight glare probability DGP in an annual simulation ^[5].

Why early planning is decisive

Window size, room depth, sill height, glazing and shading by neighbouring buildings determine daylight quality. These parameters are defined in preliminary and concept design. A daylight simulation at this stage shows whether the agreed level is achieved and avoids costly rework. At the same time, the need for artificial light – and therefore energy consumption – can be reduced.

Frequently asked questions

Is EN 17037 mandatory?

The standard is not automatically part of building regulations. It becomes binding when agreed contractually or required by certification systems.

Which level makes sense for homes?

The standard does not specify this. In practice, at least the "minimum" level is often aimed for in occupied rooms; the decision is made for each project.

Sources (in German)

Author: Paul Rostand Ndjeundoun, M.Sc. (Hons), Certified Lighting Expert (LiTG), Registered European Lighting Expert · As of November 2026. Standard values have been carefully researched but do not replace consulting the currently valid edition of the standard.