There's something quietly radical happening in health-conscious homes: people are stockpiling light bulbs that governments around the world have effectively banned.
Since 2012, the European Union has phased out traditional incandescent bulbs. The United States strengthened restrictions in 2023. The message was clear: these energy-guzzling relics had to go, replaced by efficient LEDs that use a fraction of the electricity.
But here's what the energy efficiency experts didn't talk about: the bulb we banned might have been one of the healthiest light sources ever created.
The Spectrum That Evolution Designed Us For
To understand why, you need to know something about light that most people never consider — not all light is created equal.
When Thomas Edison perfected the incandescent bulb in 1879, he didn't just create light. He created a continuous spectrum of wavelengths that closely mimics sunlight itself. Heat a tungsten filament to around 2700 Kelvin, and it produces what physicists call "blackbody radiation" — a smooth, unbroken range of light from warm reds through the visible spectrum and into the near-infrared.
This isn't marketing language. Research confirms that "incandescent light spectrum is closest to the natural sunlight spectrum," while modern alternatives show significant gaps and artificial peaks in their output.
For hundreds of thousands of years, humans evolved under two light sources: the sun during the day, and fire at night. Both produce continuous spectra. Both are warm. Both include substantial infrared radiation. The incandescent bulb is, essentially, an electric campfire — and our biology recognizes it as such.
What We Lost When We Switched
Modern LED bulbs, for all their efficiency advantages, work on a fundamentally different principle. Most white LEDs use a blue LED chip with a phosphor coating that converts some of that blue light to other colors. The result is a spectrum with sharp peaks and notable gaps — particularly a strong blue spike at 450 nanometers.
Even "warm white" LEDs retain this blue peak. Even expensive, high-quality LEDs can't replicate the continuous spectrum of an incandescent filament.
Why does this matter? Four reasons:
First, blue light at night is a biological problem. Our circadian system — the master clock that regulates sleep, hormones, and metabolism — is exquisitely sensitive to blue wavelengths. Blue light suppresses melatonin production about twice as effectively as other wavelengths. When you're exposed to blue-enriched LED light in the evening, your brain interprets it as daylight and delays your natural sleep onset.
Incandescent bulbs, by contrast, are naturally suited for evening use. As one health lighting expert notes, "From a physiological perspective, incandescent lighting is generally considered less disruptive to the human circadian rhythm compared to blue-rich LED lighting."
Second, incandescent bulbs produce near-infrared radiation — wavelengths between 700-1000 nanometers that LEDs don't emit at all. While the health significance of this is still being researched, emerging evidence suggests near-infrared light may stimulate mitochondrial function, increase cellular energy production, and provide tissue-protective effects. Professor Glen Jeffery at University College London notes that "molecules in our cells absorb infrared wavelengths, influencing numerous biological and chemical processes."
We don't yet know the long-term consequences of living in environments completely devoid of infrared light. We're running an unintended experiment on ourselves.
Third, color rendering — how accurately light reveals the true colors of objects — is perfect with incandescent bulbs. They score 100 on the Color Rendering Index, the reference standard against which all other lights are measured. This isn't just aesthetic. Our visual system evolved to interpret color under continuous-spectrum light. Under artificial LED spectra with gaps and spikes, color perception requires more effort, potentially contributing to eye strain.
Fourth, incandescent bulbs are inherently flicker-free. The thermal mass of the filament smooths out fluctuations in AC power, creating steady light. LEDs require electronic drivers that can introduce flicker — and while quality LEDs have minimized this problem, low-cost options can flicker at frequencies that cause headaches and visual discomfort in sensitive individuals.
The Energy Efficiency Trade-Off
None of this means incandescent bulbs are perfect. Their energy inefficiency is real — only about 5-10% of the electricity they consume becomes visible light, with the rest becoming heat. In an era of climate change and rising energy costs, this matters.
But here's what's worth considering: the health costs we can't easily quantify.
What's the cost of disrupted sleep? Of living under artificial spectra our eyes weren't designed for? Of raising children in environments with unprecedented light patterns? We're only beginning to understand the full implications of our modern lighting environment.
A recent study found that LED screen blue light "unambiguously links" to detrimental impacts on sleep quality, duration, and circadian regulation in students. The October 2024 report from the International Energy Agency confirmed the existence of "blue light hazard" while noting special concern for children and night workers.
The Strategic Approach
So what's a health-conscious person to do?
The most practical approach isn't an all-or-nothing choice. It's strategic combination.
Use incandescent or halogen bulbs where light quality matters most and where you spend significant time in the evening:
- Bedroom lamps and ceiling fixtures
- Living room table and floor lamps
- Reading lights and desk lamps used after sunset
- Dining areas where you want food to look appetizing and natural
- Bathrooms where you need accurate color for grooming
Use quality LEDs for spaces where efficiency matters more than spectrum:
- Overhead ambient lighting
- Utility areas, garages, basements
- Outdoor lighting
- Spaces primarily used during daytime
One expert recommends this exact strategy: "Use full spectrum incandescent light bulbs at close range in table, desk, and floor lamps, and LED bulbs in overhead fixtures — a great way to get the health benefits of incandescent with the energy efficiency of LED."
The Availability Challenge
The elephant in the room: incandescent bulbs are increasingly difficult to find. Regulations have tightened globally, and major manufacturers have largely discontinued production.
However, certain categories remain available in most markets:
- Rough service bulbs (designed for vibration resistance)
- Specialty and decorative bulbs
- Some halogen types (which offer similar spectral benefits)
- Appliance bulbs
- Heat lamp bulbs
These loopholes exist because total prohibition proved impractical. And for those prioritizing health over efficiency in key areas of their home, they represent an option worth considering.
The Bigger Picture
The story of incandescent bulbs is a case study in how single-metric optimization — in this case, energy efficiency — can have unintended consequences.
Nobody disputes that reducing electricity consumption is important. But when we made that the only consideration, we inadvertently changed the light environment humans are exposed to in ways we're only now beginning to understand.
The healthiest light remains sunlight — full spectrum, dynamic, bright during the day and absent at night. After that, the closest thing we've created is the incandescent bulb. Not because it's high-tech or efficient, but precisely because it's simple: a heated filament producing the same spectrum as the fires our ancestors sat beside for millennia.
Modern LED technology is improving. High-CRI warm white LEDs with enhanced red spectrum and minimal flicker are becoming available. The gap is narrowing. But it hasn't closed.
Until it does, that "obsolete" incandescent bulb sitting in your bedside lamp might be doing something important — providing your eyes and circadian system with the kind of light they recognize as safe as the sun goes down.
Sometimes the old way persists not despite progress, but because of something progress overlooked.