The best temperature for sleep is a cool bedroom. For adults, the published figures I'd go by run from 16°C, BC Hydro's night setting for saving energy, to 20°C, the top of Sleep Foundation's adult range. HealthLink BC, the province's health information service, asks for a bedroom that is "quiet, dark, and cool" and gives no number at all.
Bedroom temperature here means the air in the room overnight, not the warmth under the covers. Older adults are the exception worth knowing about. In a 2023 study of 50 adults aged 65 and over, sleeping in their own homes, sleep was most efficient when the bedroom ran between 20 and 25°C. Health Canada recommends 26°C as the upper indoor limit for people 60 and over, day and night.
I co-own Merit Home Furniture and work at our Duncan store on Vancouver Island. I sell beds and bedding, not medical advice, so each health figure below belongs to the source named beside it.
Best temperature for sleep in Celsius, source by source
None of the Canadian health bodies I checked publishes one best temperature for sleep. Asked for the optimal temperature for sleeping in Celsius, the six sources below give six answers, written for different reasons.
| Source | Figure, and what it's for |
|---|---|
| HealthLink BC | "Quiet, dark, and cool," with no number, on its page about sleeping better |
| Sleep Foundation (US) | A thermostat at 15.6 to 20 degrees Celsius (65 to 68°F) for adults |
| BC Hydro | 16 degrees Celsius when sleeping or away in winter, an energy-saving setting rather than health advice |
| Baniassadi and colleagues, 2023 | Between 20 and 25°C for the most efficient sleep, in 50 adults aged 65 and over |
| Health Canada | 26°C as the upper indoor limit for adults 60 and over, day and night |
| Canadian Paediatric Society | No number for babies: a room that is comfortable for you is comfortable for your baby |
A 16°C room and a 25°C room each sit inside somebody's range, so the answer depends on the sleeper, the bedding and the person's age. Of the numbers, only Health Canada's limit and the older-adult study rest on measured health data. For a healthy adult, I'd start near the cool end and change the bedding before touching the thermostat.
Why does a cool room help you fall asleep? Body temperature through the night
A cool room helps because the body sheds heat as sleep begins. Kazue Okamoto-Mizuno and Koh Mizuno reviewed the research on heat, cold and sleep in the Journal of Physiological Anthropology in 2012. They describe core temperature dropping at sleep onset while blood flow to the skin of the hands and feet opens up. That heat loss goes with falling asleep quickly, the review says, and a hot, humid room slows it.
The same review gives 29°C as the neutral room temperature for people sleeping with almost nothing on. Under blankets and pyjamas the comfortable room is much cooler, because the bed builds its own warm climate around the sleeper.
Is it better to sleep with socks on?
Socks may help someone with cold feet fall asleep sooner, on small evidence. In a 2018 study in the same journal, Ko and Lee of Seoul National University had six young men sleep in a 23°C lab room. Wearing feet-warming bed socks, they fell asleep 7.5 minutes sooner on average and slept 32 minutes longer. Six sleepers is a very small group, so I'd read it as a reason to try a pair on a cold night, not as proof.
What happens when the bedroom is too hot, and is it too cold to sleep?
A bedroom that's too hot disturbs sleep more than one that's too cold, once blankets and pyjamas are in the picture. The Okamoto-Mizuno review found that heat brings more waking and less deep sleep and dream (REM) sleep, in young and older sleepers alike. In older people, it adds, even mild heat increases waking and doubles sweat loss through the night.
Cold is gentler on sleep itself, by the review's account. With enough bedding the stages of sleep weren't affected, and one study it cites found no difference in sleep between 9°C and 20°C in older adults. The authors add a caution: cold can still change the heart's responses during sleep without the sleeper noticing, and they call for more study of it. So a cool room under warm covers suits most healthy adults, but I wouldn't shrug off a cold bedroom for an older parent.
Is it safe to sleep with a fan on?
A fan is fine for comfort in ordinary summer heat, and it isn't enough on its own in a heat wave. Health Canada says fans can help you feel more comfortable but are ineffective at cooling the body over 35°C. HealthLink BC sets the bar lower: above 30°C, it says, fans alone may not be able to prevent heat-related illness. Health Canada also suggests opening windows at night, if it's safe, to let cooler air in.
Best room temperature for sleep by age: babies, adults and older adults
The best room temperature for sleep shifts with age, and the sources are firmest at the two ends of life.
For babies, the worry is overheating. The Canadian Paediatric Society says overheating increases a baby's risk of SIDS, sudden infant death syndrome. It gives no number, only a test: if the room is comfortable for you, it's comfortable for your baby. It advises a properly fitted one-piece sleeper and no blankets. The Public Health Agency of Canada adds that babies don't need a hat indoors, because it can make them too hot.
For adults, the Canadian 24-Hour Movement Guidelines set 7 to 9 hours of good sleep for ages 18 to 64. From 65 on, the guidelines from the Canadian Society for Exercise Physiology set 7 to 8 hours.
Older adults have the clearest numbers. Amir Baniassadi and colleagues at the Marcus Institute for Aging Research in Boston tracked 50 people aged 65 and over, reporting in Science of the Total Environment in 2023. Bedroom sensors and a ring-style sleep tracker gave 10,903 person-nights of data. Sleep was most efficient between 20 and 25°C, and efficiency fell 5 to 10% as the room went from 25 to 30°C. The best temperature also varied a lot from one person to the next.
Health Canada's guidance recommends an upper indoor limit of 26°C for adults 60 and over. It says sustained exposure between 26°C and 31°C should be avoided, especially overnight. HealthLink BC adds that people 65 and older may be less likely to sense and respond to high temperatures. It suggests checking on older adults in the evening, when indoor temperatures are highest.
What the 2021 heat dome showed about bedroom temperature
The BC Coroners Service's death review panel looked at the heat dome of June 25 to July 1, 2021. It counted 619 heat-related deaths in the province. In 98% of them the heat injury happened indoors, at home. Of the people who died, 67% were 70 or older and 56% lived alone. The Island Health region recorded 55 of the deaths.
The panel found that "high indoor temperature was the primary cause of injury and death". Outdoor air cooled at night, but homes didn't, and indoor readings stayed above 26°C through the event. For an older relative living alone, a cooler room or a cooler place to go is worth settling before the next heat warning.
Duncan's summer and winter nights, and BC Hydro's thermostat temperatures
Duncan's climate gives bedrooms cool nights most of the year. These are Environment and Climate Change Canada's 1981 to 2010 normals for the Duncan Kelvin Creek station, whose records run 1987 to 2007, before the heat dome.
| Duncan Kelvin Creek normal | Value |
|---|---|
| July, average daily high | 24.7°C |
| July, average daily low | 11.1°C |
| January, average daily low | 0.3°C |
| Days above 30°C, per year | 7.9 |
| Nights at or below 0°C, per year | 79.2 |
An average July night outside drops to about 11°C, so there's usually cooler air to let in after dark.
BC Hydro's winter setting is 16 degrees Celsius when sleeping or away. For summer, BC Hydro recommends 25 degrees Celsius on an air conditioner.
Heat pumps get different advice. BC Hydro says they're most efficient at a consistent temperature, so its line is "set it and forget it". It asks owners not to turn a heat pump down at night, and to make seasonal changes of no more than two degrees at a time. It also suggests heat or cool mode rather than auto. Those are energy settings, and for an older relative on a hot night, Health Canada's 26°C ceiling is the number I'd watch.
Summer sleep on the Island
Close curtains or blinds on sunny windows during the day, as Health Canada suggests, and open windows at night if it's safe. Run a heat pump on cool, not auto. Strip the bed to a sheet and a light cover you can push off.
Winter sleep on the Island
Leave a heat pump steady overnight, per BC Hydro. Add a layer to the bed before adding degrees to the room. Socks are worth a try for cold feet, on the small study above.
Bedding layers for summer and winter sleep: sheets, protectors and pyjamas
Bedding is the cheapest way to change how warm a bed sleeps. These are the Health Guard sheets and mattress protectors Merit lists for the Duncan store, described the way their listings describe them. Prices run from the smallest size to the largest, before applicable taxes, as listed on November 1, 2026.
| Health Guard item | What the listing says, and price |
|---|---|
| Bamboo Cotton sheet set | Bamboo cotton, white, fits mattresses up to 18 inches deep; $99.00 to $159.00 |
| Luxury Microfiber sheet set | Brushed 100% polyester, listed as moisture-wicking; $49.00 to $69.00 |
| Tencel Dream protector | Tencel surface the listing says "wicks moisture and sleeps cool," waterproof and breathable; $109.00 to $149.00 |
| Cotton Touch protector | Natural cotton surface with a waterproof backing; $89.00 to $129.00 |
| Cool Ice protector | Cooling-fabric surface the listing says is built for hot sleepers, waterproof and breathable; $189.00 to $249.00 |
| Premium Terry protector | Terry towelling over a quiet waterproof membrane; $49.00 to $79.00 |
The protector sits between the sheet and the mattress, so a plastic-feeling one can make any bed sleep warmer. None of these is a medical product. The trade-offs between types are laid out in what each kind of mattress protector is for.
Merit's cotton-blend set is Health Guard's bamboo cotton. In summer I'd pair a cool-surface protector with that set or the microfiber one. In winter the protector stays, and the warmth comes from the layers on top.
If the heat seems to come from the mattress itself, coil beds and cooler covers for hot sleepers covers that. Pillow height and fill are in how to pick a pillow that suits your sleep position.
On wool against cotton pyjamas, one study stands out. Chin Moi Chow and colleagues, in Nature and Science of Sleep in 2019, put 36 healthy adults aged 50 to 70 in a 30°C sleep lab. In the over-65 group, wool sleepwear took them to sleep in 12.4 minutes, against 26.7 minutes in cotton. The authors call the benefits small, and Australian Wool Innovation, funded by woolgrowers and the Australian government, supported the work.
What else in the bedroom affects sleep besides temperature
Light and noise make up the rest of HealthLink BC's quiet, dark and cool. Its page on sleeping better suggests curtains or blinds against light, and soothing music or a white noise machine against sound. If light and noise still bother you, it suggests a sleep mask and earplugs.
Some sleep sites also say to clear the clutter, which I can't find a Canadian health source measuring. A bedside table with a drawer at least keeps the charger off the bed, and setting the nightstand level with the mattress top keeps a water glass in easy reach.
None of the sources I checked sets a separate bedroom temperature for sleep apnea, breathing that stops for short periods during sleep. HealthLink BC names obstructive sleep apnea as the most common type, central as less common, and both together as complex. HealthLink BC says to call a doctor about loud, heavy snoring with daytime sleepiness, or a partner who stops breathing, gasps or chokes in sleep.
What is the forbidden hour of sleep?
The "forbidden hour" comes from a 1986 paper by the sleep researcher Peretz Lavie, in Electroencephalography and Clinical Neurophysiology. He gave 22 sleep-deprived volunteers, across three experiments, short and repeated chances to nap. He found a "forbidden zone" for sleep centred around 8 to 10 p.m., between an afternoon dip and the main night-time sleepiness. Those were small groups after a night without sleep, so it's a pattern, not a bedtime rule.
Before buying anything for a bed that sleeps hot or cold, I'd put a cheap thermometer on the nightstand for a week. Then I'd change one layer at a time, the protector first and the sheets next, so you can tell which change made the difference.
Heat illness during sleep: warning signs, 8-1-1 and when to call 9-1-1
Heat illness is a health problem first. No sheet, protector or mattress at Merit treats it, and a cool-surface protector can't cool a 30°C room. HealthLink BC says the symptoms range from mild to severe. Its list includes heavy sweating, muscle cramps, dizziness or fainting, headache, nausea and very dark urine. Further down it lists a core body temperature of 39°C or more, unusual confusion, and red, hot, dry skin.
| What to do | When, per the source |
|---|---|
| Call 9-1-1 | Heat stroke is suspected; keep trying to cool the person until help arrives (HealthLink BC) |
| Call 9-1-1 | Someone has a high body temperature and is unconscious or confused, or has hot, red, dry or damp skin (Health Canada) |
| Contact a health care provider | Symptoms aren't mild, last longer than an hour, change, get worse or cause concern (HealthLink BC) |
For help deciding, dial 8-1-1 anywhere in BC to reach HealthLink BC, which can connect you with a health professional. For the deaf and hard of hearing, the number is 7-1-1. Night sweats are a different matter from a warm room. HealthLink BC says to talk to your doctor if you often have them, or have fever, chills, pain or unplanned weight loss along with them.
Where the sleep temperature figures come from
- HealthLink BC, Sleeping Better (current as of November 7, 2022), checked November 2026.
- HealthLink BC, Heat-related illness, HealthLink BC File 35 (updated June 5, 2026), checked November 2026.
- HealthLink BC, Night Sweats (current as of November 14, 2022), checked November 2026.
- HealthLink BC, Sleep Apnea (current as of November 7, 2022), checked November 2026.
- Health Canada, Guidance on upper indoor temperature limits: Protecting the health of older adults (2026), checked November 2026.
- Health Canada, It's much too hot! Protect yourself from extreme heat, checked November 2026.
- Canadian Paediatric Society, Caring for Kids, Safe sleep for babies, checked November 2026.
- Public Health Agency of Canada, Safe sleep for your baby, checked November 2026.
- Canadian Society for Exercise Physiology, Canadian 24-Hour Movement Guidelines, checked November 2026.
- Okamoto-Mizuno K and Mizuno K, Effects of thermal environment on sleep and circadian rhythm, Journal of Physiological Anthropology 31:14 (2012), checked November 2026.
- Baniassadi A and others, Nighttime ambient temperature and sleep in community-dwelling older adults, Science of the Total Environment 899:165623 (2023), checked November 2026.
- Ko Y and Lee JY, Effects of feet warming using bed socks on sleep quality, Journal of Physiological Anthropology 37:13 (2018), checked November 2026.
- Chow CM and others, The impact of sleepwear fiber type on sleep quality under warm ambient conditions, Nature and Science of Sleep 11:167-178 (2019), checked November 2026.
- Lavie P, Ultrashort sleep-waking schedule III: gates and forbidden zones for sleep, Electroencephalography and Clinical Neurophysiology 63(5):414-425 (1986), checked November 2026.
- BC Coroners Service, Extreme Heat and Human Mortality: A Review of Heat-Related Deaths in B.C. in Summer 2021 (2022), checked November 2026.
- Environment and Climate Change Canada, Canadian Climate Normals 1981 to 2010, Duncan Kelvin Creek, checked November 2026.
- BC Hydro, news release on bedroom temperature and the recommended thermostat settings (2021), checked November 2026.
- BC Hydro, Heat pump mythbusters tackle key questions (2022), checked November 2026.
- BC Hydro, Six degrees of preparation: your thermostat needs you, checked November 2026.
- BC Hydro, Cold comfort: the rising use (and cost) of air conditioning in B.C. (2018), checked November 2026.
- Sleep Foundation, Best Temperature for Sleep (Danielle Pacheco, medically reviewed by David Rosen, MD, updated July 11, 2025), checked November 2026.
- Merit Home Furniture's listings for the Health Guard sheets and protectors named here, prices and store lists read November 1, 2026, and the Duncan store's pickup and delivery terms.
Asking about sheets and protectors at our Duncan store
Merit's Duncan store is at 107 Ingram St and is open Monday to Saturday, 9 to 5. The Health Guard sheets and protectors above are listed for Duncan, and a call tells you what's on hand to feel before you decide. Merit Duncan keeps a strict no-pressure policy, so there's time to compare fabrics.
Sheets and protectors aren't shipped. They're picked up free at the Duncan store, usually about 2 business days after they arrive there, or added to a furniture or mattress delivery. Delivery from Merit Duncan costs $150 across the Island, with setup and assembly included, as our Duncan delivery and pickup terms set out.
Call the Duncan store, (250) 746-5527
Our mattress, pillow and sleep guides for Island homes are gathered on one page. The sheet sets we list and every mattress protector and pad sit in their own collections.