Keep Bedroom Cool and Dark

What is it?

Keeping your bedroom cool and dark means optimizing your sleep environment by maintaining a temperature between 60-67°F (15-19°C) and eliminating light sources that disrupt your circadian rhythm. This involves simple adjustments like using blackout curtains, removing electronic devices, and managing your thermostat or ventilation.

The goal is to create an environment that naturally signals to your body that it's time for deep, restorative sleep. Your bedroom becomes a sleep sanctuary rather than just another room where you happen to close your eyes.

How does it work?

Your body's core temperature naturally drops when preparing for sleep, triggering the release of melatonin—the hormone that regulates your sleep-wake cycle. A cool room supports this natural temperature decline, making it easier to fall asleep and stay asleep through the night.

Darkness plays an equally critical role. Even small amounts of light can suppress melatonin production, confusing your internal clock. Your eyes contain photoreceptors that detect light even through closed eyelids, sending signals to your brain that it's still daytime. By eliminating light, you remove this interference and allow your circadian rhythm to function as designed.

Why adopt it?

Quality sleep affects everything: your mood, focus, immune system, metabolism, and long-term health. Most people struggle with sleep not because of complex disorders, but because their environment is working against them.

A cool, dark bedroom can reduce the time it takes to fall asleep by up to 50% and increase deep sleep phases—the stages where your body repairs tissue, consolidates memories, and processes emotions. You'll wake up feeling genuinely refreshed rather than groggy, improving your productivity and mental clarity throughout the day. Unlike supplements or elaborate routines, this hack leverages your body's natural biology without side effects or ongoing costs.

How to adopt it (First steps)?

Install blackout curtains or blinds. These block external light from streetlamps, early sunrises, or neighboring buildings. Look for curtains with thermal backing—they'll also help regulate temperature.

Cover or remove electronic devices. LED lights from chargers, alarm clocks, and standby indicators create surprising amounts of ambient light. Use electrical tape to cover small lights or remove devices entirely from the bedroom.

Set your thermostat to 65-67°F (18-19°C) before bed. If you don't have air conditioning, open windows for cross-ventilation in the evening, use a fan, or try cooling your sheets by placing them in the freezer for 10 minutes before bed.

Use a sleep mask if needed. If blackout solutions aren't fully possible, a comfortable sleep mask provides portable darkness. Choose one with contoured eye cavities that don't press on your eyelids.

Test your room with the "hand test". Once you think it's dark enough, hold your hand in front of your face. If you can see your hand's outline, there's still too much light entering your space.

Challenges and how to overcome them

"I share my room with a partner who prefers warmth". Compromise by keeping the room cool but using separate bedding—they can layer blankets while you use lighter sheets. Heated mattress pads on one side offer individual temperature control.

"My room gets too hot in summer". Use breathable bedding like cotton or bamboo sheets, point a fan toward your bed, or try the "Egyptian method"—dampen a sheet and sleep under it with a fan running. The evaporation creates a cooling effect.

"Complete darkness makes me anxious". Use a dim red light nightlight near the floor. Red wavelengths have minimal impact on melatonin production compared to blue or white light, providing enough visibility without disrupting sleep chemistry.

Supporting apps/tools

Blackout curtains — Nicetown, Eclipse, or IKEA Majgull offer affordable options with strong light-blocking capabilities.

Smart thermostats — Nest or Ecobee can automatically lower temperature on a schedule and monitor bedroom conditions.

Sleep masks — Manta Sleep Mask, Alaska Bear, or simple contoured masks from drugstores.

Temperature monitoring — SensorPush or govee thermometer/hygrometer helps you dial in the perfect temperature over time.

White noise machines or fans — Dohm sound machine or a simple box fan masks disruptive sounds while providing cooling airflow.