White LED light keeping Spain awake: the complaint uniting half the country

The war against white light that keeps people awake

Why do more and more people say white LED lights are ruining their sleep? The complaint keeps repeating itself: streetlights that stay on all night at full intensity, commercial signs sweeping across the facade opposite, and the impossibility of sleeping with the window open. The discomfort is not just aesthetic. Some link it to sleep problems and a general feeling of unwellness they attribute to the flickering of these fixtures, known as flickering.

The issue has political ramifications. The decision by US Health Secretary Robert F. Kennedy Jr. to reverse the ban on manufacturing traditional incandescent bulbs has become a banner for those advocating a return to warm light. In Spain, European regulations do address colour temperature in office buildings, but not in public street lighting or in homes.

What science says about cool light and sleep

The debate over colour temperature has a technical basis. Light is measured in kelvin: below 3,000 it is considered warm, around 4,000-5,000 is neutral, and above 6,000 it is classed as cool. Some argue that cool white light is harmful outside the central hours of the day because it disrupts circadian rhythms, and that night-time exposure to that part of the spectrum affects mood. Against this stands the argument that the perception of "more light" is misleading: what matters is lumens, not tone.

Technical consensus, however, is not complete. In work environments requiring visual quality control, such as fruit and vegetable warehouses, a colour temperature of 5,000 K is recommended to better detect peine and defects in produce. In bathrooms, neutral 4,000 K light reproduces true colour best. Things get complicated when that criterion is applied to a bedroom.

The public lighting nobody regulates

The most frequently cited case is that of the Calar Alto astronomical observatory in Almería, which faces growing light pollution problems from the street lighting of nearby towns. The comparison with France, where many rural areas are left completely dark in the early hours, illustrates the contrast. In the Canary Islands, by contrast, sky protection rules are enforced more strictly.

In the domestic sphere, the range of cases is wide: some people have replaced all their bulbs with 2,700 K or lower models, even 2,200 K on bedside tables, while others resort to incandescent and halogen bulbs bought online. Complaints about town councils installing light fixtures with no criteria mix with criticism of commercial premises that choose cool light for aesthetic reasons.

Why warm light illuminates less (and it's not entirely false)

There is a physical explanation for some shops' preference for cool white: at equal power, LED lamps with a cool temperature deliver higher lumen output than warm ones. Add the age-related loss of optical sensitivity, and the result is that many older people choose white light because they "see better". The problem is that this criterion, valid for a kitchen or a workshop, gets carried over into the living room and the bedroom.

According to the most widely accepted guidance, the solution is to reserve warm light for rest areas and neutral light for bathrooms and kitchens. Cool light above 6,000 K, on the other hand, has no place in the home. And yet it keeps being installed in streetlights, shop windows and glowing signs that nobody turns off.

In the end, the underlying complaint is not aesthetic: it is that the light meant to illuminate the street has become a coexistence problem that no one has legislated on. And meanwhile, the window stays closed.