What noise level do I need in a bedroom to sleep well?

The WHO guideline is 35dB for undisturbed sleep, and 30dB for a genuinely quiet bedroom. Untreated London bedrooms on main roads typically measure 52-62dB overnight, so a 25-30dB reduction is the target.

Will secondary glazing make my bedroom stuffy?

No. Sliding and hinged units open fully for summer ventilation. Where a room faces a source that is loud around the clock, acoustic trickle ventilation or a mechanical unit maintains airflow without breaking the seal.

Should I choose 6.4mm or 10.8mm laminate for a bedroom?

On a quiet residential street, 6.4mm is usually sufficient. On any bedroom facing a bus route, rail corridor or flight path, specify 10.8mm at a 150mm minimum cavity — the low-frequency content otherwise remains audible.

How much does bedroom secondary glazing cost?

From £480 per window with 6.4mm acoustic laminate, or from £620 for a main-road specification with 10.8mm laminate at a 150mm cavity. Two-bedroom packages start at £1,180.

Secondary Glazing for Bedrooms

The one room where the dB number decides whether you sleep.

Get a fixed quote 0207 060 1572

35dB

WHO night-time guideline

52-62dB

Typical untreated London bedroom

54dB

Achievable reduction

£480

From, per window

The World Health Organization sets 35dB as the guideline for undisturbed sleep and 30dB as the level for a genuinely quiet bedroom. A London bedroom on any main road, bus route or rail corridor typically measures 52-62dB overnight — 20-30dB above the target.

Bedrooms are where we recommend spending the acoustic budget. A quiet bedroom with a noisy reception room is a liveable house; the reverse is not.

Why the sleep threshold matters

Sleep disruption is driven by peak events, not the average level. A single 65dB bus pass-by will trigger a micro-arousal even if the room average is acceptable. Reducing peaks below roughly 35dB stops the arousal response, which is why the specification targets peak reduction rather than an averaged figure.

30dB: quiet bedroom, no measurable sleep effect
35dB: WHO guideline for undisturbed sleep
45dB: measurable increase in night-time awakenings
55dB+: substantial sleep disruption and cardiovascular stress markers

Ventilation without losing the seal

The commonest objection to bedroom glazing is stuffiness. Sliding and hinged units both open fully, so summer ventilation is unaffected on quiet nights. Where a bedroom faces a source that is loud around the clock, we discuss acoustic trickle ventilation or a mechanical unit so you are not forced to choose between air and quiet.

Getting the specification right first time

Bedroom windows are the ones we most often see under-specified. A 6.4mm unit on a shallow cavity produces a real improvement, and then the occupant discovers the bus rumble is still there at 05:00. On any bedroom facing a bus route, rail line or flight path we recommend 10.8mm laminate at 150mm minimum from the outset.

Bedroom specification

Target internal level: Below 35dB at peak events
Glass: 10.8mm acoustic laminate on main-road, rail and flight-path elevations
Cavity: 150mm minimum for low-frequency sources
Opening style: Sliding for daily use, hinged for maximum seal
Ventilation: Full opening retained; acoustic trickle vents available
System performance: Up to 54dB

Pricing guide

Specification	Price	Notes
Standard bedroom sash, 6.4mm	from £480	Quieter residential streets
Main-road bedroom, 10.8mm	from £620	150mm cavity
Two-bedroom package	from £1,180	10.8mm throughout
Free acoustic sound survey	Free	Overnight dB profile available

All prices supplied and fitted in London, inclusive of survey and 25-year warranty. See the full secondary glazing price list.

Case study: Master bedroom on the Wandsworth one-way system

Wandsworth, SW18

Problem: 62dB overnight average with 71dB peaks; occupant waking 4-6 times per night.

Solution: Two 10.8mm acoustic laminate sliders at a 160mm cavity with acoustic trickle ventilation.

Result: 30dB reduction to a 32dB overnight level; self-reported awakenings down to zero or one per night.

Frequently asked questions

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