Natural Light in Interior Spaces, High quality LED Lighting

It is commonly acknowledged that natural light stands out as the optimal illumination for human well-being, a preference rooted in the history of humanity. However, the contemporary pace of life and lifestyle choices prompt a more comprehensive examination of the lighting conditions prevalent in industrialized societies today. In contrast to artificial lighting, natural light exhibits significant variability in terms of quantity, direction, and spectral power distribution, primarily influenced by factors such as the time of day, meteorological conditions, latitude, orographic features, and urban context.

While the desirability of natural light for interior illumination in buildings is evident, it also poses certain challenges. Direct sunlight, for instance, can be disruptive due to its intensity and carries radiation, including potentially harmful ultraviolet (UV) rays and heat-inducing infrared (IR) rays. Excessive exposure to these elements can have adverse effects on health and lead to increased energy consumption for air conditioning in warm weather.

Unlike artificial light, natural light is characterised by considerable variability in terms of quantity, direction and spectral power distribution, High quality LED bulbs

Positive aspects

Nevertheless, the positive aspects of natural light in indoor spaces are widely recognized. Studie on the use of lightpipes, and others exploring the integration of natural light in interior environments, underscore its positive impact.

Dar Lighting Jared 2 Light Wall Light In Matt Black Finish With Round Clear Dimpled Glass JAR0922-12
Clear Dimpled Glass
Dar Lighting Feya Wall Light In Antique Bronze With Champagne Dimpled Glass
Antique Bronze
Dar Lighting Hadano Single Wall light In Natural Brass With Dimpled Glass Shade
Natural Brass

The lighting industry

Compared to artificial lighting, which is in the order of tens of lux outside and hundreds of lux inside, natural light is therefore up to three orders of magnitude greater. ISO and CIE have published an international standard that defines the luminous properties of natural light so that it can be considered in lighting design calculations. This standard defines a mathematical model is employed to determine the luminance distribution at different sky positions as observed from the ground.

These calculations consider both the time of day and varying climatic conditions, ranging from clear skies to overcast conditions. Contemporary Computer-Aided Design (CAD) software for lighting integrates calculation models, such as the CIE (Commission Internationale de l Eclairage) or equivalent models. These models enable the accurate computation of the contribution of natural light within interior spaces, taking into account the dynamic interplay of daylight with environmental factors.

Physical aspect in the architectural and engineering design of the building, from lighting bases to modern automatic systems for the management and filtering of natural light, both for new buildings and for those undergoing renovation. There is also a trend, which presumably will become more generalised in the future, towards a new and increasingly integrated design methodology, in which the lighting designer intervenes from the early design stages of a building, in collaboration with architects and engineers, for the definition of all aspects concerning lighting, both artificial and natural.

Searchlight 7508 Stainless Steel LED Outside Wall Lamp

Portion of daylight hours

The employed workforce, actively engaged in various occupations, predominantly spends a significant portion of daylight hours outside their homes. In contemporary society, work within enclosed environments is largely concentrated in offices, exhibiting diverse layouts yet commonly featuring individual work desks, meeting tables, visual display unit workstations, and other functional spaces.

An essential consideration for future lighting design lies in understanding the circadian attributes of the light that permeates these interior spaces. This assessment is crucial for shaping the illumination conditions conducive to the well-being and productivity of individuals within these work settings.

Lighting Showroom

Quintiesse QN-HEATH-S-MB Heath Small Wall Lantern In Mottled Finish With Seeded Glass IP44
Quintiesse
Dar Wisebuys Nakita Wall Light In Antique Brass With Dimpled Glass
Nakita Wall Light
Quintiesse QN-HEATH-M-MB Heath Medium Wall Lantern In Mottled Finish With Seeded Glass IP44
Quintiesse

For future designs

As part of an in-depth exploration into lighting design for sustainable homes in the future, ENEA commissioned the Laboratorio Luce at the Politecnico di Milano to investigate whether the presence of natural light within a home can positively impact the human circadian system. The study focused on a common living space model: a traditional three room flat situated in a city block of flats.

To assess circadian stimulation, the research initially simulated natural lighting conditions using a three dimensional model created with a lighting Computer-Aided Design (CAD) system. This simulation aimed to develop a practical methodology for future designs. Subsequently, in the second phase, radiometric measurements were conducted to determine circadian stimulation during two distinct periods of the year.

The main furnishings in the rooms have been inserted in order to correctly position the viewpoints of the observer for the different activities considered and plausible in a residential context. Given that individuals engaged in work activities are typically at home for a limited percentage of their daytime throughout the year, our focus has shifted towards those more prone to spending extended diurnal hours at home specifically, the elderly. To assess the impact of lighting on individuals in terms of circadian system adjustment, we concentrated on the visual system of an aging population, categorizing individuals aged 60 and above as elderly users.

Correlation

This age threshold was chosen not only due to potential shifts in social activities and roles, such as retirement, but primarily because it aligns with physiological changes in the human visual system. Around the age of 60, various physical changes occur, affecting vision and giving rise to issues such as presbyopia and potential lens problems.

Levels of knowledge

The Time Factor and the Activities. The circadian cycle, being time-dependent, has been carefully considered in relation to the flat's occupants, particularly the elderly. The day has been segmented into three distinct periods, each associated with different Non-Image Forming (NIF) lighting effects:

Morning (6:00 - 10:00): This period emphasizes the synchronization of the circadian biological clock through illuminance derived from natural light, fostering concentration and productivity in most individuals.

Mid-morning and Afternoon (10:00 - 18:00): Higher levels of lighting during this timeframe can enhance alertness and concentration.

Late Afternoon and Night (18:00 - 6:00): During these phases, exposure to circadian light should be minimized to avoid a decrease in melatonin production and maintain cortisol levels. Failure to do so could lead to a disruption of the normal human circadian cycle, causing desynchronization with the solar day.

Mantra M5392 Infinity Brown Oxide LED Flush Ceiling Light

The positive effects of light

Based on these temporal divisions, a comprehensive daily scheme has been developed. This scheme considers three key moments of light exposure, strategically placed in different rooms of the flat to align with specific activities and corresponding to the natural rhythms of sleep-wake cycles and meal times (breakfast, lunch, and dinner). This daily rhythm contributes to the synchronization of the circadian system.

The scheme serves as a practical tool for identifying the likely locations of users throughout the day, correlating with the amount of light required for optimal circadian system functioning during those specific periods. It is adaptable based on the nature of activities to be carried out and is structured according to the lifestyle of the occupants.

Also with reference to the time factor, another element to take into consideration is the duration of exposure to light in the various phases of the day. In fact, in order to have an effect on the circadian system, it is necessary to have a longer exposure to light than that required for vision. The human circadian system works at a much slower pace, mainly because it is based on the secretion of hormones in the blood, such as melatonin and cortisol, and less on neurological processes to synchronise the various organs of the body. It has also been known for some time.

LED Dimpled Glass Lamps

Dar Lighting Esben Table Lamp In Matt Black Finish With Round Smoked Dimpled Glass ESB4122-10
Esben Table Lamp
Dar Lighting Esben Table Lamp In Matt Black Finish With Round Champagne Dimpled Glass ESB4122-11
Dar Lighting
Dar Lighting Esben Table Lamp In Matt Black Finish With Round Pink Dimpled Glass ESB4122-13
Matt Black Finish
Dar Lighting Jared 3 Light Semi Flush Ceiling Light In Polished Gold With Champagne Dimpled Glass JAR0335-11
LED Dimpled Glass
Dar Lighting Jared 2 Light Wall Light In Matt Black Finish With Round Smoked Dimpled Glass JAR0922-10
LED Dimpled Glass
Dar Lighting Jared 3 Light Semi Flush Ceiling Light In Matt Black With Round Smoked Dimpled Glass JAR0322-10
Semi Flush Ceiling Light

Lighting for premature infants

The measurements have confirmed that, in the winter period, natural light is not able to correctly stimulate the circadian system throughout the day, even in the presence of different weather conditions, similar to what has been determined by the simulation using a lighting CAD.

Dar Lighting Nitya 5 Light Ceiling Pendant Light In Mottled Copper Finish NIT0564

Circadian lighting, CAD simulation

The fact that the CAD simulation on the one hand underestimates the amount of light in many situations, due to the choice of reflection factors set for the surfaces, but on the other hand overestimates the CCT of the light actually present in the environment, leads to two errors with an opposite sign, which tend to partially offset themselves, in the evaluation of the circadian stimulation through the CAD simulation.

Globe Edison Screw Vintage LED Filament 3.5 watt Bulb With Amber Finish - Dimmable
Vintage LED Filament
Dar Lighting Nitya 8 Light Ceiling Pendant Light In Mottled Copper Finish NIT0864
Ceiling Pendant
Endon Lighting 94503 Star LED Filament Bulb Lamp
Star LED Filament

Our body's internal clock

Years of physiological research underscore the crucial importance of circadian lighting for our well-being. In terms of design methodology, it is imperative to steer clear of oversimplifications. Labeling a light source or lighting product as inherently circadian or human-centric is fundamentally inaccurate.

This is because the evaluation of circadian lighting needs to be conducted at the eye level, considering the typical positions of individuals within specific indoor environments. Furthermore, it is influenced by natural and artificial light sources, as well as the comprehensive impact of project elements, including walls and furnishings, on the ambient light. Circadian lighting, therefore, is intricately tied to the entirety of the lighting project, taking into account human presence, the spaces involved, the activities conducted, and the temporal dimension.

Technologies can anyway provide useful tools to design a circadian lighting system. In this sense, LEDs provide fundamental characteristics to create lighting products that previous light sources did not make possible, or made only partially possible, with scarce efficiency and high costs.

Time for a change.