Noise is waking you, and a sound reading at night will show when
A sound is what wakes you, so the first thing to check is how loud your bedroom gets at night, recorded at pillow height with a phone.
In short: Record one night at pillow height, count the spikes that rise well above the background, then deal with the source behind them.
What to check
| What to check | Specification |
|---|---|
| What to measure | The separate loud events of the night: how loud each one gets, when it happens, and how far it rises above the steady background. WHO guidance suggests measuring the number of noise events, as well as the difference between the maximum sound level and the background sound level (WHO, Guidelines for Community Noise). |
| The instrument | A phone sound-meter app with A-weighting that logs the peak (LAmax) and the average (LAeq) across the night. In NIOSH laboratory testing, a phone app met the testing criteria (± 2 dB mean difference from the reference type 1 sound level meter), but over a range of 65 to 95 dB (CDC NIOSH). In a separate study, apps overestimated room ambient noise levels < 50 dB (American Journal of Speech-Language Pathology). |
| The range that matters | Inside the bedroom, 30 dB LAeq for continuous noise and 45 dB LAmax for single sound events (WHO, Guidelines for Community Noise). Outside, at the front of the building, the night guideline is 40 dB Lnight, the level above which adverse effects such as self-reported sleep disturbance and environmental insomnia are observed (Noise and Health, WHO night noise guidelines summary). |
| Where to put it | On the bedside surface at pillow height, uncovered, and away from a fan or a charger. The research judges reactions per event in relation to levels at the ear of the sleeper (WHO, Night Noise Guidelines for Europe). |
| What to change first | Start with the bedroom window before anything else. WHO's bedroom figures assume the noise reduction from outside to inside with the window partly open is 15 dB (WHO), while the night noise guidelines used a value of 21 dB as average insulation (WHO). If the peaks come from inside the home, move or switch off that source first. |
Why this follows from your answers
You said a sound woke you, which puts noise ahead of heat, light and air as the first cause to rule in or out. It is also the one cause a phone can log through a single night, with a time attached to every event. That time stamp is the whole point of the reading. A phone cannot confirm a quiet room, because the same study found apps may not accurately verify rooms below 50 dB. What it can show is a spike at 4:10 on the night the sleeper woke at 4:10.
The floor changes the likely source. A top-floor room holds summer heat, so its window stays open longer and lets in the street, along with rain and wind on the roof. A middle floor puts footsteps, doors and shared pipes first, while a ground-floor or basement room sits nearest the pavement and its traffic.
What changes it
The season you named moves the likely source. Worst in summer points at the open window and at early light, which can wake a sleeper at the same moment a passing car does. The guide to choosing blackout curtains for a bedroom covers the light side. Worst in winter means a shut window, so the source is more likely inside, such as a boiler firing or pipes ticking as they heat and cool. Worst all year points at something constant, such as a fridge, a lift shaft or a main road. Peaks matter more than the average, and the same WHO report cites research suggesting indoor levels should not exceed approximately 45 dB LAmax more than 10–15 times per night (WHO).
What to check on your own bed
Set the phone at the head of the bed before sleep, screen up, and leave it logging until morning. Write down the times you woke, then lay them against the peaks in the log. If the peaks match and come from outside, compare 1 night with the window closed against 1 night with it open. The guide to ventilating a bedroom in winter without losing the heat covers keeping air moving while it is shut. If they come from inside, the time stamp usually names the source, such as a boiler timer or a fridge compressor. Where a noise cannot be removed, a steady sound can blur each peak, as the guide on whether white noise helps you sleep explains. If no peak lines up with a waking, noise may not be the cause, and the next check is what temperature a bedroom should be for sleep.