What colour night light is best for babies? Why brightness matters more
It is 2am and the landing light is spilling across the nursery floor.
When parents ask what colour a night light should be, the more useful answer is about brightness. Start with how bright the room is, rather than whether the glow looks warm or cool. A dim, warm light you can just see by is the sensible starting point. A night light will not stretch the night or teach sleep; it is there so that feeds, check-ins and a frightened child feel calmer.
How bright is too bright for a small bedroom?
Light is measured in lux, which is how much light lands on a surface. The first study below describes typical indoor lighting as under 200 lux and bright indoor lighting as 300 to 1,000 lux.
Melatonin is the hormone that rises in the evening and signals to the body that it is night-time. In a very small 2018 study, Akacem and colleagues measured what bright evening light did to it. Ten children aged three to five completed it, spending one hour in around 1,000 lux ending at bedtime, after a dim evening below 15 lux for comparison. Their melatonin fell by about 88%, and was still low 50 minutes after the light went off.
That is a room light left on full, not a small bedside glow. The study varied brightness only. It did not test colour, it did not include babies, it did not test a night light, and it measured a hormone rather than sleep itself.
Your own sitting room is the useful reference. If the nursery feels as bright as downstairs with the big light on, it is brighter than bedtime needs to be.
Why a warm colour did not rescue a bright room
The usual advice is that warm light is safe for sleep and blue-ish light is not. The evidence in children is more careful than the one-liners, and it is often reported loosely.
Lee and colleagues, also in 2018, studied 22 children, mean age 8.9 years, and 20 adults under evening light of about 300 lux, measured at eye height - ordinary room lighting, not a night light. Different groups of children sat under warm white at 3000 K or blue-enriched white at 6200 K. These were school-age children, not babies or toddlers.
Under the warm light, the children's melatonin fell by 58.1%. Under the blue-enriched light, it fell by 81.2%. Adult melatonin fell by 30.4% in both conditions. Warm was the less disruptive of the two for these children, and it still did not leave them unaffected.
Brightness first, colour second. Warm remains the better choice for a night-time glow, as a cautious rule and because it is easier to live with. It is not a shield that lets a bright room through.
Are red night lights better for babies?
Red is the colour most often recommended for a baby's room. The reasoning given is that the body clock responds most strongly to blue light and least to red, so a red glow of the same brightness should disturb it less than a blue-white one.
As reasoning, that is fair enough. What is missing is the part that applies to your nursery. Neither study above tested red. Neither included babies. Neither went anywhere near the brightness of an actual night light. No one has shown that a red night light helps a baby sleep, and no one has shown that a warm amber one is worse.
So treat red as a reasonable default rather than a fix. If you already have a warm amber light your baby settles with, there is nothing here that says replace it. If you are choosing from scratch, red or amber is a sensible preference - and how dim you can turn it down still matters more than which of the two you pick.
If you are choosing a night light, look for one built for a low, warm glow rather than full room lighting. The current listing for our NestiFox night light describes it as designed for a low-level glow, not to replace room lighting. Our nursery night lights page lists the glow and colour options for each model.
What none of this measured
None of the research gathered for this article measured light at night-light brightness in children. The lowest levels in the two studies above are their own dim comparison evenings, below 15 and below 30 lux, used as controls rather than as tested conditions. The figures parents get quoted come from room light of roughly 300 to 1,000 lux.
The ages matter too. The bright-light study covered three to five year olds. The colour study averaged nearly nine years. None of it reaches babies, and school-age findings should not be quietly stretched down to a newborn.
What the NHS actually says
NHS guidance on sleep and young children gives a practical, two-part answer. If your child is afraid of the dark, it suggests a night light or a landing light left on. If your child wakes during the night, it advises keeping things boring and leaving the lights off.
NHS Healthier Together, an NHS clinical-network programme, puts the bedroom rule for ages three to five plainly: turn lights off or keep them very dim. That page says nothing about colour and never mentions night lights, so we will not stretch it to either.
Together, that is the position. Darkness is the default. A small, dim glow has a place where fear of the dark is the reason, or where you need just enough light to feed or check safely. A night waking on its own is best handled with the lights left off.
One change to make tonight
Dim the house in the last hour before bed, rather than shopping for a new bulb colour. Turn the ceiling light off and use the lowest light you can still move around by.
Keep the night light as dim as it can be and still do its job, low down and away from your child's face. If it is there for feeds, switch it off again once you have finished. If fear of the dark is not the reason it is there, try a night waking with the lights off. Once your child is a toddler who handles the light, our toddler night light guide covers what to check.
Warm and red tones are easier to live with at night than blue-white light. Choose dim first, then warm. If the real problem is a 5am start rather than the light, that is a different question, and our guide to whether ok-to-wake clocks work covers what those colour signals can and cannot do.
What we still do not know
What a dim night light does to a child's melatonin, in either direction, is not something this research can answer. Both were small and short, at light levels far brighter than a night light. The figures above, with their ages and brightness attached, are what was actually measured.
If a dim glow makes your evenings calmer and more predictable, that is reason enough to keep it. If your child sleeps well in the dark and is not frightened of it, there is no reason to add one.
Safety note: a bedside light is not a toy. An adult should set it up, on a stable surface outside the cot, bed or sleep space, never under bedding. Keep cables and chargers away from the sleeping area, and follow the supplied user guide and any warnings.
References
- Akacem LD, Wright KP Jr, LeBourgeois MK. "Sensitivity of the circadian system to evening bright light in preschool-age children." Physiological Reports 6(5):e13617, 4 March 2018. pmc.ncbi.nlm.nih.gov/articles/PMC5835497
- Lee S, Matsumori K, Nishimura K, et al. "Melatonin suppression and sleepiness in children exposed to blue-enriched white LED lighting at night." Physiological Reports 6(24):e13942, 2018. pmc.ncbi.nlm.nih.gov/articles/PMC6295443
- NHS. "Sleep and young children." nhs.uk/baby/health/sleep-and-young-children
- NHS Healthier Together. "Healthy Sleep - Child 1 to 5 years." healthiertogether.nhs.uk/child-under-5-years/healthy-sleep