Quick Answer: True incandescent Edison-style bulbs produce a melatonin suppression value of 1.5%, compared to 12.3% for cool white LED — an 8x difference, according to a 2026 study in Scientific Reports testing 52 lamps. Their warm 2200-2700K spectrum is genuinely better for pre-sleep lighting, not just aesthetically pleasant. Pair with a dimmer switch and use in the three hours before bed for maximum benefit.
In This Guide
Reading Time: 12 minutes
Edison-style filament bulbs have been everywhere in bedroom design for the past decade — café strings, exposed-filament pendants, amber nightstand lamps. The aesthetic appeal is obvious: the warm glow looks like candlelight at scale, and bedrooms decorated with them photograph beautifully.
What most people do not know is that the aesthetic case and the sleep science case for these bulbs point in exactly the same direction. The same warm amber light that looks romantic and nostalgic is also, by measurable physiological criteria, significantly better for your melatonin production than the alternatives. There are now peer-reviewed papers with specific numbers.
Why Edison Lights Landed in Bedrooms
The Edison bulb revival began around 2010 and coincided with a broader design movement toward industrial and vintage aesthetics. The exposed filament — the glowing tungsten element visible through clear glass — became a design feature rather than something to hide inside a frosted globe. The warm amber colour temperature (typically 2200-2700K, compared to daylight at 6500K) gave spaces the quality of older incandescent lighting that most people associate with comfort and home.
Part of the appeal was also reaction. The early LED and CFL transition produced harsh, cool-white lighting that felt clinical in domestic spaces. Edison-style bulbs — or LED versions that mimic their spectral output — offered an alternative.
For bedrooms specifically, the form followed a genuine function. The bedroom is where lighting transitions from task (getting dressed, reading) to pre-sleep preparation. The lighting environment in the hours before sleep affects the onset time and quality of sleep more than most people realise — and warm, dim light is not merely aesthetically preferable, it is physiologically beneficial.
The Melatonin Numbers: What Your Bedroom Bulb Actually Does
The most useful recent data comes from a 2026 study by Bailes and Lucas published in Scientific Reports (DOI: 10.1038/s41598-025-29882-7). The researchers tested 52 household lamps of various types and measured the melatonin suppression value (MSV) of each — a standardised measure of how much melatonin production the light would suppress per unit of illumination.
The results were stark:
| Lamp Type | Colour Temperature | Melatonin Suppression Value |
|---|---|---|
| Traditional incandescent (Edison-style) | 2200-2700K (amber) | 1.5% |
| Tunable LED at warmest setting | 2100K | 0.1% |
| Warm white LED | ~2700K | 3.6% |
| Cool white LED | ~4000-5000K | 12.3% |
| Cool white CFL | ~4000K | 12.1% |
| Standard overhead fluorescent (4100K) | ~4100K | High (comparative context) |
Traditional incandescent Edison bulbs at 1.5% MSV produce roughly 8x less melatonin suppression than cool white LED at 12.3%. For every unit of light produced, they suppress significantly less of the melatonin that prepares your body for sleep.
Why Colour Temperature Affects Melatonin
The human circadian system contains specialised photoreceptors called intrinsically photosensitive retinal ganglion cells (ipRGCs). These cells contain melanopsin, a photopigment maximally sensitive to short-wavelength (blue) light at approximately 490 nanometres. Cool white light sources (LEDs, fluorescents, screens) have high blue-spectrum content. Warm amber incandescent light — like Edison bulbs — has very low blue content. The ipRGC pathway signals the suprachiasmatic nucleus (the circadian pacemaker) to suppress melatonin production. Less blue light in the evening means less suppression, earlier melatonin onset, and faster sleep preparation.
A separate study by Sanchez-Cano et al. (2025) in Life (Basel) (PMC: PMC12113466) measured melatonin levels over three hours of evening light exposure to either red-spectrum or blue-spectrum LED. The difference at two hours: participants under warm/red light had melatonin at 26.0 pg/mL versus 7.5 pg/mL under blue light. By hour two, warm-spectrum exposure produced approximately 3.5x more melatonin than blue-spectrum — and this gap continued widening through hour three.
The practical implication: the effect accumulates. Reading under warm Edison light for two hours before bed is substantially better for sleep preparation than reading under cool white LED for two hours.
True Incandescent vs. LED Filament Edison: A Spectral Difference That Matters
The market now offers both true incandescent Edison bulbs and LED filament bulbs designed to replicate their appearance. They are not equivalent from a sleep-science standpoint, even when both are labelled "2700K."
True incandescent bulbs produce light through thermal radiation — a heated tungsten filament radiates across a continuous spectrum, with most energy in the infrared and red portions and relatively little in the blue-ultraviolet range. This matches closely with fire and candlelight, the light sources humans evolved under.
LED filament bulbs use phosphor-converted LEDs — a blue LED chip coated with yellow phosphor that shifts the apparent colour to amber-white. The colour temperature label (2700K) describes the visual appearance, but the underlying spectrum retains a blue-spike characteristic of LED technology. The warm appearance and the spectral output are not the same thing.
The Bailes and Lucas (2026) study captured this: warm white LEDs at ~2700K produced 3.6% MSV — more than double the 1.5% of true incandescent, despite appearing similarly warm. If true melatonin preservation is the goal, traditional incandescent filament bulbs outperform LED filament imitations even at matching colour temperatures.
True incandescent bulbs consume more energy and run hotter — practical downsides that the LED alternatives solve. The tradeoff is real and worth knowing about. For a bedside lamp used for 90 minutes of pre-sleep reading, the higher energy cost of a true 40W incandescent versus a 4W LED equivalent is modest in absolute terms.
Dorothy, Sleep Specialist: "We often talk about the sleep environment as a whole — the mattress, the pillow, the temperature, the darkness level. Lighting is part of the same picture and it is one of the cheaper things to improve. Replacing overhead cool LEDs with a warm incandescent bedside lamp is a small change that the research genuinely supports. It is one of the few things I can say with confidence actually makes a measurable biological difference."
The Three-Hours-Before-Bed Rule
A 2022 international expert consensus paper in PLoS Biology (Brown et al., PMC8929548), authored by 13 circadian researchers, translated the laboratory findings into specific household recommendations. For the evening period — defined as the three hours before intended sleep — the recommendation is:
- Maximum 10 melanopic lux at eye level
- Light spectrum should be depleted in short wavelengths (blue-poor)
- In the sleep environment: maximum 1 melanopic lux (effectively, darkness or very dim red/amber nightlight)
Melanopic lux — a measure of light weighted by its effect on the melanopsin system — differs from standard photopic lux. A 2700K warm light can meet the 10 melanopic lux threshold at a photopic lux level that still allows comfortable reading and task work. The same photopic lux from a cool white source would significantly exceed the melanopic lux threshold.
The three-hour window aligns with the observation that melatonin onset typically begins 2-3 hours before the body's usual sleep time. The Gooley et al. (2011) study in the Journal of Clinical Endocrinology & Metabolism (PMC3047226) found that standard room light before bed delayed melatonin onset by approximately 94 minutes — nearly the full pre-sleep melatonin window — and reduced melatonin duration by 90 minutes. The light used in that study was cool 4100K fluorescent, which helps explain why converting to warm Edison lighting shows such marked benefit.
Dimmer Switches: The Second Variable
Colour temperature is one variable. Intensity is the other, and the interaction matters.
A 2024 study in Building and Environment (Nie et al., DOI: 10.1016/j.buildenv.2024.111221) found something counterintuitive: 2800K light at higher illuminance outperformed 5800K light on both sleep quality and next-day cognitive performance. This challenges the assumption that always choosing dim and warm is optimal — at warm colour temperatures, moderate brightness may actually outperform very dim conditions.
The practical takeaway is that a dimmer switch gives you control over the second variable. Starting the evening at moderate brightness with warm light (adequate for task work without blue-spectrum stimulation), then reducing intensity further as bedtime approaches, allows you to use the full two-variable optimisation rather than committing to either fully bright or fully dim.
A dimmer switch paired with a true incandescent or warm LED Edison bulb is the most flexible and physiologically appropriate bedroom lighting setup available at consumer prices.
For Families With Teenagers
The adolescent sensitivity finding from Nagare et al. (2019) in Light Research and Technology (PMC6561500) is worth noting for families. The study found that adolescents showed significantly greater melatonin suppression from cool white (5600K) light compared to warm (2700K) light — a 43% vs 29% suppression difference. Adults showed a smaller but directionally similar difference.
Teenagers already experience a biological phase delay — their circadian rhythm shifts toward later sleep times during puberty, making it genuinely harder to fall asleep early. Bedroom lighting that further suppresses melatonin compounds this. In homes with teenagers, replacing cool overhead lighting with warm bedside Edison lamps may provide more benefit than it would for adults.
Practical Setup Guide for an Edison Bedroom
The Four-Layer Bedroom Lighting Setup
Layer 1: Overhead lighting (task and general)
Keep overhead lighting at a neutral white (3000-3500K) for daytime use. Add a smart switch or smart bulb that allows you to shift to 2700K warm mode in the evening. Alternatively, use a separate warm floor lamp or table lamp and switch off the overhead entirely after dinner.
Layer 2: Bedside lamp (pre-sleep reading)
Edison filament bulb, 25-40W true incandescent equivalent, on a dimmer. This is the most important single lamp in the bedroom from a sleep science standpoint. Position at reading height — not directly above eye level. Choose a shade that diffuses the light downward rather than toward the face.
Layer 3: Ambient accent (optional)
Edison string lights or warm-globe pendants create the low-level ambient glow often seen in bedroom decor photography. These work well as the final lighting stage before sleep — very low lux, warm spectrum, no overhead component.
Layer 4: Sleep environment (darkness)
The expert consensus recommendation is 1 melanopic lux maximum during sleep — effectively darkness. Blackout curtains and eliminating standby LED indicators from electronics support this. Any nightlight should be red or deep amber, not white or blue.
A Brantford Note on Bedroom Environments
At Mattress Miracle, we have helped Brantford families with their sleep environments since 1987 at 441½ West Street. Lighting comes up regularly in conversations about sleep quality — particularly when customers have already invested in a good mattress but are still sleeping poorly. The sleep environment is a system, and lighting is one of the cheaper variables to improve. Our team is happy to talk through the full picture during a showroom visit.
Frequently Asked Questions
Are real incandescent Edison bulbs still available in Canada?
Canada phased out most incandescent bulbs under efficiency regulations that came into force in stages through 2014-2015. True incandescent bulbs are no longer sold as general-purpose lighting. However, "rough service," "vibration-resistant," and speciality incandescent categories remain legal. The practical alternative is a high-quality LED filament bulb at 2200K-2700K with a high CRI (90+) — this produces a closer spectral match to true incandescent than standard warm-white LED, though still with the blue-spike characteristic noted above.
What colour temperature is best for a bedroom?
For pre-sleep lighting, 2200K-2700K is the recommended range. At these colour temperatures, blue-spectrum content is minimised and melatonin suppression is lowest. A 2026 Scientific Reports study found true incandescent (which operates in this range) suppresses melatonin at 1.5% compared to 12.3% for cool white LED. For daytime use and task work, a warmer neutral (3000-3500K) is adequate without the strong circadian stimulation of cool white.
How much does bedroom lighting actually affect sleep quality?
The Gooley et al. (2011) study found standard cool overhead room light before bed delayed melatonin onset by approximately 94 minutes and reduced melatonin duration by 90 minutes. A randomised controlled trial by Shechter et al. (2018) found amber blue-light blocking before bed added 52 minutes of total sleep time in chronic insomnia sufferers. These are not trivial effects. Bedroom lighting is one of the more underrated sleep environment variables.
Is dimming a cool white LED equivalent to using a warm bulb?
No. Dimming reduces lux (intensity) but does not shift colour temperature. A cool white LED dimmed to low intensity is still producing a blue-weighted spectrum — just less of it. For equivalent melatonin preservation, you need both warm colour temperature (2200-2700K) and low intensity. Dimming warm bulbs provides both benefits simultaneously; dimming cool bulbs provides only the intensity reduction.
Do Edison lights affect teenagers differently?
Yes — adolescents show greater melatonin suppression from cool-spectrum light than adults, per Nagare et al. (2019). The study found 43% suppression under cool 5600K light versus 29% under warm 2700K light in adolescents. Given that teenagers already experience a biological phase delay that makes early sleep harder, reducing blue-spectrum evening light exposure may provide proportionally more benefit in teenage bedrooms than in adult bedrooms.
Sources
- Bailes, H. J., & Lucas, R. J. (2026). Home lighting melatonin suppression values: incandescent vs. LED. Scientific Reports, 16, 2850. DOI: 10.1038/s41598-025-29882-7.
- Brown, T. M., et al. (2022). Recommendations for daytime, evening, and nighttime indoor light exposure to best support physiology, sleep, and wakefulness in healthy adults. PLoS Biology, 20(3): e3001571. PMC8929548.
- Sanchez-Cano, A., et al. (2025). Comparative effects of red and blue LED light on melatonin levels during three-hour exposure in healthy adults. Life (Basel), 15(5), 715. PMC12113466.
- Nagare, R., Plitnick, B., & Figueiro, M. G. (2019). Effect of exposure duration and light spectra on nighttime melatonin suppression in adolescents and adults. Light Research and Technology, 51(4), 530-543. PMC6561500.
- Gooley, J. J., et al. (2011). Exposure to room light before bedtime suppresses melatonin onset and shortens melatonin duration in humans. Journal of Clinical Endocrinology & Metabolism, 96(3): E463-E472. PMC3047226.
- Shechter, A., et al. (2018). Blocking nocturnal blue light for insomnia: a randomized controlled trial. Journal of Psychiatric Research, 96, 196-202. PMC5703049.
Visit Our Brantford Showroom
We are located at 441½ West Street in downtown Brantford. Free parking available, wheelchair accessible. Our team does not work on commission, so you get honest advice based on your needs.
Mattress Miracle — 441½ West Street, Brantford, ON — (519) 770-0001
Hours: Monday–Wednesday 10am–6pm, Thursday–Friday 10am–7pm, Saturday 10am–5pm, Sunday 12pm–4pm.
If you are working on your sleep environment and want to talk through the full picture — mattress, pillow, temperature, and lighting — come in and we will help. Call and ask for Talia, or use our chat box outside store hours, available almost any time we are not sleeping.