Street noise at night: how to get back to sleep
The World Health Organization recommends less than 30 dB of ambient noise for restorative sleep. A busy street at night generates 55 to 70 dB with the window closed in a standard dwelling. The gap to fill is 25 to 40 dB, which no single solution can entirely resolve. The most effective combination without major renovations: custom soundproof curtain (22 dB attenuation*) + new window seals (3-5 dB) + white noise to mask the residue (5-10 dB perceived).
This guide starts from your real situation (what noise, what level, what impact on your sleep) and builds a concrete protocol to regain sleep, step by step, with expected results in decibels at each stage.
What is the noise level in your bedroom at night?
Before looking for a solution, measure the problem. Nighttime noise varies considerably depending on your environment. You can measure yours for free with a sound level meter app on your smartphone (Decibel X, Sound Meter, NIOSH SLM), accurate to within 2-3 dB.
| Nighttime environment | Typical level (window closed) | Impact on sleep |
|---|---|---|
| Countryside, quiet cul-de-sac | 25-35 dB | No problems, WHO threshold respected |
| Quiet residential street | 35-45 dB | Slight, normal falling asleep, rare awakenings |
| Moderately busy street | 45-55 dB | Delayed falling asleep by 15-30 min, micro-awakenings |
| Boulevard, main road | 55-65 dB | Disrupted sleep, frequent awakenings, chronic fatigue |
| Very busy road, bar area | 65-75 dB | Sleep impossible without protection, sleep debt |
The WHO defines three critical thresholds for nighttime noise:
- Less than 30 dB: undisturbed sleep. This is the goal.
- 30-40 dB: possible awakenings in sensitive individuals. Measurable biological effects (increased heart rate, reduced deep sleep).
- Over 40 dB: confirmed harmful effects on health. Increased stress, blood pressure, and long-term cardiovascular risk (source: WHO, Environmental Noise Guidelines for the European Region, 2018).
The night protocol: 4 steps to regain sleep
Step 1: Replace window seals (gain: 3-5 dB)
This is the quickest and cheapest step. Worn seals let noise through the frame's gaps, even with the window closed. A 1 mm gap around the window is enough to let in a significant amount of noise.
Cost: 5 to 15 euros per window. Time: 30 minutes. Gain: 3 to 5 dB, mainly on high-pitched noises (whistles, loud voices) that pass through leaks.
Result after step 1: If your room is at 60 dB, it drops to 55-57 dB. Perceptible but insufficient improvement.
Step 2: Install a custom soundproof curtain (gain: 18-22 dB)
This is the step that makes the biggest difference. A custom soundproof curtain of 620 g/m² attenuates up to 22 dB* of noise passing through the window. The curtain must be closed during sleep, which is natural since it also blocks 100% of light* (essential for melatonin production).
Critical configuration for sleep:
- Overlap of 15 to 20 cm on each side (sound bypasses a curtain that is too narrow)
- Floor length (2-3 cm gap, no more)
- Rod at least 10 cm above the frame
Cumulative result after steps 1+2: If your room was at 60 dB, it drops to 33-37 dB. This is within the WHO zone for possible sleep (30-40 dB). For a street at 70 dB, the result is 43-47 dB: significantly improved but still above the optimal threshold.
Step 3: Add masking white noise (perceived gain: 5-10 dB)
White noise (uniform sound across all frequencies) does not reduce street noise in actual decibels, but it masks sound peaks (horns, motorcycles, shouts) which are the main cause of nocturnal awakenings. The brain perceives peaks less when a constant background noise "drowns" them out.
A study published in the Journal of Caring Sciences (2016) showed that white noise reduces the time to fall asleep by 38% in a noisy hospital environment. In domestic conditions, the perceived gain is 5 to 10 dB on sound peaks.
Options:
- Smartphone app: free (myNoise, White Noise, Noisli). Place the phone on the bedside table.
- Dedicated white noise machine: 20 to 60 euros. More reliable than a phone (no notifications, battery).
- Fan: the hum of a fan produces natural white noise. Double function in summer.
Cumulative result after steps 1+2+3: The residual noise of 33-47 dB is partially masked by white noise. Sound peaks (the most disruptive for sleep) are drowned out. The overall perception drops to 28-40 dB depending on the street. For most situations, sleep becomes possible again.
Step 4: Additional optimizations (gain: variable)
If the first 3 steps are not enough (exceptionally noisy street at 70+ dB, bars downstairs, night construction):
- Silicone earplugs: 20 to 30 dB additional reduction. Possible discomfort for some sleepers. Custom-molded models (audiologist, 50-100 euros) are more comfortable than disposable models.
- Double curtain (sheer + soundproof curtain): 1 to 2 dB additional gain compared to the curtain alone. Marginally useful.
- Window draft stopper: 1 to 2 dB on noise passing under the frame. Complementary to seals.
Summary table: the complete protocol
| Step | Solution | Gain | Cost | Installation time |
|---|---|---|---|---|
| 1 | New window seals | 3-5 dB | 5-15 € | 30 min |
| 2 | Custom soundproof curtain (620 g/m²) | 18-22 dB* | 80-350 € | 5 min (existing rod) |
| 3 | White noise (app or machine) | 5-10 dB (perceived) | 0-60 € | Immediate |
| 4 | Earplugs (if needed) | 20-30 dB | 5-100 € | Immediate |
Cumulative gain steps 1+2+3: 26 to 37 dB of total reduction (actual + perceived). This is enough to transform a 65 dB street into a 28-39 dB environment, within the WHO zone for restorative sleep. Total cost: 85 to 425 euros. No construction, no authorization.
Why sound peaks are more disruptive than constant noise
Constant noise (traffic background at 50 dB) is bothersome, but the brain partially adapts to it within 10 to 20 minutes (habituation phenomenon). Sound peaks (motorcycle at 80 dB for 3 seconds, horn at 90 dB, shout at 75 dB) trigger an alert reaction from the nervous system that causes nocturnal awakenings.
This is why the soundproof curtain is particularly effective for sleep: it does not eliminate all noise, but it clips the peaks. A motorcycle at 80 dB with a 22 dB* curtain drops to 58 dB. It is still audible, but the peak is sufficiently reduced to no longer trigger the alert reflex. White noise (step 3) further masks these residual peaks.
Melatonin bonus: why blackout improves sleep beyond noise
A Kurtens soundproof curtain (620 g/m²) also blocks 100% of light*. Light is the second biggest sleep disruptor after noise. Exposure to just 5 to 10 lux (a streetlight filtering through a thin curtain) delays melatonin production by 30 to 60 minutes (source: Gooley et al., Journal of Clinical Endocrinology & Metabolism, 2011).
By installing a single custom soundproof curtain, you simultaneously address the two main causes of poor sleep: noise (22 dB attenuation*) and light (0 lux). Thermal insulation (up to 7 °C gain*) comes as a bonus. To learn more about the impact of light on sleep, consult our article blackout curtain for bedroom: the guide to perfect sleep.
*Data from tests conducted under optimal conditions.
Frequently Asked Questions
How to sleep with street noise?
The most effective combination without major renovations: new window seals (3-5 dB, 5-15 euros) + high-density custom soundproof curtain (18-22 dB*, 80-350 euros) + white noise to mask residual peaks (5-10 dB perceived, 0-60 euros). Cumulative gain: 26 to 37 dB. Sufficient to transform a 65 dB street into 28-39 dB, within the restorative sleep zone recommended by the WHO (less than 30 dB ideal, less than 40 dB acceptable).
How many decibels are needed for good sleep?
The WHO recommends less than 30 dB for undisturbed sleep. Between 30 and 40 dB, biological effects are measurable (increased heart rate, reduced deep sleep). Above 40 dB, harmful health effects are confirmed (stress, blood pressure, cardiovascular risk). Source: WHO, Environmental Noise Guidelines for the European Region, 2018.
Does white noise really help with sleep?
Yes. White noise does not reduce ambient noise in actual decibels, but it masks sound peaks (horns, motorcycles, shouts) that cause nocturnal awakenings. A study published in the Journal of Caring Sciences (2016) shows a 38% reduction in the time to fall asleep in a noisy environment. White noise is more effective when used in conjunction with a soundproof curtain (which reduces baseline noise) than when used alone.
Is a soundproof curtain enough to sleep street-side?
For a moderate street (50-55 dB at night): the curtain alone (22 dB*) brings it down to 28-33 dB, within the WHO zone for restorative sleep. For a busy street (60-70 dB): the curtain brings it down to 38-48 dB, which significantly improves comfort but may still be above the ideal threshold. Combining with new seals (+3-5 dB) and white noise (5-10 dB perceived) bridges the gap for most situations.
How to measure noise in my bedroom at night?
Download a free sound level meter app (Decibel X, Sound Meter, NIOSH SLM) on your smartphone. Place the phone on your bedside table, with the window closed, at the time when noise bothers you (usually 10 PM - 2 AM). Note the average level and peaks. The accuracy is 2-3 dB, sufficient to evaluate your situation and choose the right solutions.
What budget to regain sleep in a noisy apartment?
Minimum effective budget: new seals (5-15 euros) + custom soundproof curtain (80-350 euros) + free white noise app = 85-365 euros. Full budget: add molded earplugs (50-100 euros) if the street is exceptionally noisy = 135-465 euros in total. Compare this to the cost of acoustic double glazing (500-1,500 euros/window) or moving.
Are earplugs a good solution for sleeping?
Earplugs reduce 20-30 dB of noise, which is very effective. But they have drawbacks: discomfort for some sleepers (especially foam models), risk of not hearing fire alarms or alarm clocks, and an unpleasant feeling of isolation. They are a good complement (step 4) when the curtain + seals + white noise are not enough, but not the first-line solution. Custom-molded models (50-100 euros from an audiologist) are significantly more comfortable than disposable ones.
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