“I want a bright house” is often one of the first desires expressed by those having their new house built. And for good reason: natural light is one of the essential elements of comfort in the home. Beyond aesthetics, it plays a fundamental role in our health, our safety and our energy consumption. Homes bathed in a natural lighting are simply more pleasant to live in, which is why the concept must be worked on by the home builders in the same way as the creation of beautiful volumes, the arrangement of rooms or the thermal comfort.
A bright house: only positive points
A healthy home is always bright
Humans are profoundly photo-dependent! Light affects our bodies from every angle, regulating metabolic and immunological processes. Absorbed by the skin, in particular to synthesize essential vitamin D, it reduces the risk of visual fatigue and considerably improves mood. well-lit house Naturally helps prevent sleep disorders, stress, and even some forms of seasonal depression. For children and adults alike, brightness promotes concentration, vitality, and overall well-being.
To reinforce this topic, read the article “Building a healthy house in the South West"
Strengthening housing security
Well-lit spaces reduce the risk of falls or accidents in the home, particularly on stairs, in hallways, or in the kitchen. Natural light also improves alertness, which is valuable in high-traffic areas.
Less energy consumed
More natural light means less need for artificial lighting, even in winter. A well-oriented house also allows you to benefit from a passive solar gain to naturally heat rooms in the off-season. This results in lower consumption and a carbon footprint scaled down.
To complete the subject read the article “Optimizing the brightness of your new home: construction tips"
Natural light: orient your home according to its use
Living rooms preferably facing due south
In the living spaces (living room, dining room), a south facing allows you to enjoy maximum brightness throughout the day. A ideal orientation in winter, which is both pleasant and economical since the rays, in addition to providing light, also provide heat. In summer, the windows protected from direct sunlight remain just as bright.
Lighting adapted to each activity
Conversely, technical rooms such as the laundry room or the garage can be satisfied with a north orientation, where the light is more diffuse. This orientation can also be suitable for rooms such as the office. In fact, special attention must be paid to screens (TV, computer): avoid direct reflections, which tire the eyes and disrupt visual comfort. Well-controlled natural lighting accompanies each daily activity without disturbing.
The bedrooms should be east-facing, ideal for waking up to the soft morning light. The windows should be large enough to ensure sufficient brightness, suitable for children's development.
On the west side, you can set up an office or a reading room, taking care to control the solar gains the afternoon.
To choose the orientation of your future home, read the article “South-West: What is the best house orientation?"
Create a comfortable lighting atmosphere
To promote illumination in every corner, the depth of the rooms must be adapted to the size of the windows. To avoid areas with too much contrast, it is essential to diffuse the light inside the house. Light walls and ceilings are preferred because they reflect light well. Similarly, certain materials such as glossy tiles, glass walls, or interior skylights help diffuse it from room to room to avoid dark corners.
Crossing spaces: brightness at all times
A well-designed home lets light circulate. The ideal: through spaces, with openings on either side of the house. This not only promotes natural ventilation, but also a beautiful light distribution throughout the day.
Inside, this effect can be amplified with glass partitions, doors with glass transoms, or even glass roofs that allow light to flow from one space to another, even in the absence of direct windows.
A window in the toilet and bathroom
Natural light can also purify spaces. An excellent bactericide and antifungal, it's essential, especially in humid rooms, to maintain healthy indoor air. Therefore, the presence of windows in bathrooms and toilets isn't just necessary for indoor air quality.
Size and shape of openings: opening the house to the outside
The perception of light depends as much on its quantity as on how it enters the house. Large windows help to visually expand the space and maintain contact with the outside world. Windows, panoramic or stretched vertical openings, glazed corners or even glass roofs bring a contemporary style and bathe interiors in light. But be careful: the size must be adapted to the orientation and needs of the room to avoid glare or heat loss. Each opening becomes a true architectural element, both functional and aesthetic.
Overhead light: a valuable ally
In addition to classic openings, the roof windows provide zenithal light, that is, light that enters directly from above. It is more intense, more homogeneous, and less prone to shadows. In attics, central rooms without an exterior wall, or even above a staircase, this solution optimizes natural lighting where vertical openings are not sufficient. When well chosen and well oriented, a roof window improves both the brightness and ventilation of a space.
Focus on sunscreens
To limit glare or excessive heat gain in summer, consider solar protection: adjustable roller shutters, blinds, sunshades, or even well-placed vegetation. The goal is to reduce direct rays without depriving rooms of light. Solar-controlled glazing can also improve summer comfort while still allowing light to pass through.
Exteriors count too
The home's immediate environment directly influences the light inside. Avoid trees too close to main openings, limit south-facing roof overhangs (which can create shade in winter), and carefully choose the placement of terraces, pergolas, or sunshades. Good exterior design acts as a smart filter: it lets in light when it's beneficial, and filters it when it becomes too strong.
Natural light in the home: what do the regulations say?
If there is no brightness regulation, the public authorities, aware of the importance of natural light, have imposed a few safeguards to ensure the visual and thermal comfort of new housing.
A minimum size of glazed surface
La RE2020, which has just been strengthened in 2025, imposes a minimum surface area of bay windows equivalent to at least 1/6th of the habitable surface area of a dwelling. In other words, a house of 120 m² must have at least 20 m² of glazed surfaces (windows, bay windows, French windows, etc.). This requirement aims to:
- Promote natural lighting in living rooms,
- Reduce the need for artificial lighting,
- And improve thermal comfort by taking advantage of solar energy.
To better understand the subject, read the article “Building a bioclimatic house in Gironde: 11 tips for a cool house in summer"
Natural light integrated into the Bbio calculation
The Bbio is an indicator that allows us to calculate whether a new house takes into account the principles of bioclimatism. bioclimatic construction is a smart, economical and ecological approach that aims to design a house by taking advantage of the site's natural conditions (orientation, sunshine, prevailing winds, vegetation, etc.) to limit heating, lighting, and air conditioning needs. In RE2020, the Bbio coefficient takes into account not only insulation and orientation, but also the amount of natural light available. The better a house captures light, the better its Bbio performance. This criterion directly influences the project's compliance with regulations.
Windows in all living rooms for decent housing
Minimal lighting is also one of the criteria for decent housing. Thus, in order to be able to rent accommodation, the law requires that any room intended for living or sleeping (living room, bedroom, office, etc.) must have at least one opening to the open air. This requirement aims to guarantee good indoor air quality and a minimum amount of natural light, which are essential for the comfort and health of the occupants.
