Summary
Acoustic-specialist secondary glazing is priced on the same basic model as standard secondary glazing — materials dominate, labour is light, and the job is fitted from inside with minimal disruption — but the unit cost itself is meaningfully higher, and it's a mistake to quote it off the standard secondary glazing price ranges already published on this wiki. The uplift isn't padding or a "specialist" markup for its own sake; it comes from three real, specific cost drivers: laminated acoustic glass (which costs more to manufacture than plain float glass and is heavier, affecting frame and fixing specification), a wider sub-frame to accommodate the deeper air gap that does most of the acoustic work, and tighter compression or brush seals engineered specifically to stop sound leaking through gaps that wouldn't meaningfully affect thermal performance but would seriously undermine noise reduction.
The technical case for when acoustic-spec is the right recommendation — versus standard secondary glazing — is covered in the companion article acoustic glazing vs secondary glazing comparison. This guide assumes that decision has already been made (the client has a genuine, identifiable noise problem) and focuses purely on pricing the acoustic-specialist job correctly: by air gap width, glass spec, and size, with a worked example to show how the numbers build up on a typical domestic job.
Get this wrong in either direction and it costs you. Quote acoustic-spec at standard secondary glazing prices and the job runs at a loss once you've bought laminated glass and a proper sub-frame. Quote it too high without being able to explain why, and a client who's already seen the standard secondary glazing figures elsewhere on this wiki (or from a competitor) will query the jump and you'll struggle to justify it convincingly. Know the specific cost drivers and you can quote confidently and defend the number.
Key Facts
- Standard-size acoustic unit (supplied + fitted) — £600–£1,200 per window, for a typical domestic window opening with a 150–200mm air gap and laminated acoustic glass.
- Large or bespoke acoustic unit — £1,200–£2,500+ per window, for oversized openings, heritage/period detailing, or curved/arched units.
- Fitting time — 45–90 minutes per standard unit including making good — modestly longer than the 30–60 minutes typical of a standard secondary glazing unit, because of the heavier glass and deeper sub-frame, but still a fast job relative to the unit cost.
- Laminated acoustic glass (6.4mm+) — the core material cost driver; a laminated acoustic pane costs significantly more per unit area than the 4mm float glass used in standard secondary glazing.
- Air gap and sub-frame depth — 150–200mm gap requires a correspondingly deeper sub-frame than the 20–100mm gap typical of standard units, adding both material and, on awkward reveals, survey/fitting complexity.
- Specialist acoustic seals — compression or brush seals engineered for minimal air-gap leakage; a genuine cost item, not an upsell — a standard seal on an acoustic unit measurably undermines the noise reduction being sold.
- Materials share — 65–80% of total price (higher than standard secondary glazing's 55–75%, because the glass and sub-frame cost more while labour time increases only modestly).
- Net margin — 25–35% achievable via unit markup and a fair fitting rate, similar structure to standard secondary glazing.
- Survey importance — critical on acoustic-spec jobs specifically because reveal depth must accommodate the wider gap; a survey that doesn't confirm this risks quoting a unit that can't achieve the acoustic performance the client is paying for.
- No FENSA / Building Regs notification — as with standard secondary glazing, acoustic-spec units don't normally trigger FENSA or the Part L replacement-glazing route because the primary window is retained; check for unusual cases (e.g. where the scope of work extends beyond secondary glazing alone).
- Noise reduction achievable — up to roughly 45–50dB with a well-specified acoustic unit and full 150–200mm gap, versus roughly 20–35dB for standard secondary glazing — see acoustic glazing vs secondary glazing comparison for the technical detail.
- VAT — standard rate 20% applies; no reduced rate specific to acoustic-spec glazing.
- Typical client profile — properties near airports, railway lines, or busy arterial roads; commercial premises with a specific noise complaint; don't quote acoustic-spec by default for general cold/draught jobs where standard secondary glazing is sufficient and considerably cheaper.
Quick Reference Table
Spending too long on quotes? squote turns a 2-minute voice recording into a professional quote.
Try squote free →| Job | Air gap | Glass spec | Labour | Materials £ | Typical price £ |
|---|---|---|---|---|---|
| Standard acoustic unit, small window | 150mm | Laminated acoustic 6.4mm | 45–60 min | 450–800 | 600–950 |
| Standard acoustic unit, average window | 150–200mm | Laminated acoustic 6.4mm | 60–75 min | 550–950 | 700–1,100 |
| Large acoustic unit | 200mm | Laminated acoustic 8mm+ | 75–90 min | 700–1,200 | 900–1,400 |
| Bespoke / heritage acoustic unit | 200mm+ | Laminated acoustic 8mm+ | 90–120 min | 1,000–2,000 | 1,200–2,500+ |
| Acoustic glass upgrade on existing standard sub-frame (rare — not usually recommended) | Unchanged | Laminated acoustic 6.4mm | 30–45 min | 300–600 | 400–750 |
| Survey / measure visit (acoustic spec) | n/a | n/a | 1–2 hrs | n/a | 0–150 |
| Houseful (4–6 acoustic windows, single elevation) | 150–200mm | Laminated acoustic 6.4–8mm | 1–1.5 days | 2,800–5,500 | 3,600–6,500 |
Detailed Guidance
Why acoustic-spec costs more — the three real drivers
It's worth being able to explain this to a client rather than just presenting a bigger number, because acoustic-spec secondary glazing is a considered upgrade the client is paying extra for a specific benefit, not a generic "premium" product. First, laminated acoustic glass itself costs meaningfully more per unit area than the plain float glass used in standard units — it's a bonded, multi-layer product engineered for sound damping, not just a thicker pane. Second, the wider air gap needed to achieve the acoustic benefit means a deeper sub-frame, which is more material and, on awkward or shallow reveals, more fitting time to get right. Third, the seals themselves are a specific, higher-cost component — a standard brush seal that's perfectly adequate thermally will leak sound at a rate that meaningfully undermines the whole point of specifying acoustic glass in the first place, so acoustic-spec jobs use compression or purpose-designed acoustic seals that cost more per metre than standard secondary glazing seals.
Pricing by air gap and glass spec
As a 2026 supply-and-fit guide for a typical domestic window:
- 150mm gap, 6.4mm laminated acoustic glass — the entry point for genuine acoustic-spec performance; £600–£950 per window depending on size.
- 175–200mm gap, 6.4mm laminated acoustic glass — the sweet spot most commonly specified for road, rail or flight-path noise; £700–£1,100 per window.
- 200mm+ gap, 8mm+ laminated acoustic glass — for the most severe noise complaints or larger openings; £900–£1,400 per window.
- Bespoke, heritage or curved units at acoustic spec — combines the acoustic premium with bespoke shaping costs; £1,200–£2,500+ per window.
Always state the air gap and glass thickness on the quote alongside the price, in the same way secondary glazing pricing guide recommends for standard units — a client comparing quotes needs to see they're not comparing like-for-like against a cheaper standard-spec quote from elsewhere.
Survey — more critical here than on standard secondary glazing jobs
On a standard secondary glazing job, a survey mistake typically means a unit that doesn't fit cleanly. On an acoustic-spec job, a survey mistake can mean a unit that fits but doesn't deliver the noise reduction the client is paying the premium for, because the reveal doesn't actually accommodate the full 150–200mm gap the pricing and performance figures assume. Always confirm reveal depth at survey stage before quoting acoustic-spec, and be explicit with the client if the achievable gap is less than ideal — better to quote a realistic, achievable spec than to sell the top-end noise reduction figure and under-deliver. Charge for the survey if the property or reveal looks non-standard; on straightforward jobs it's reasonable to absorb it into the quote as with standard secondary glazing.
Labour time
Fitting time for acoustic-spec units runs a little longer than standard secondary glazing — typically 45–90 minutes per unit rather than 30–60 — because the units are heavier (laminated glass) and the deeper sub-frame needs more careful fixing, particularly on older or out-of-square reveals. It's still fast relative to the unit cost, and the day-rate structure is the same as for standard secondary glazing — see secondary glazing pricing guide for regional day-rate figures, which apply equally here.
Materials share and margin
Materials make up a higher share of the total price on acoustic-spec jobs — typically 65–80%, compared with 55–75% on standard secondary glazing — because the glass and sub-frame cost more while labour time increases only modestly. Net margin of 25–35% is realistic, built through unit markup on a trade-account price for the laminated glass and sub-frame components, plus a fair fitting rate. As with standard secondary glazing, the mistake to avoid is competing on unit price against a supply-only online seller — sell the surveyed, fitted, guaranteed acoustic performance, and be ready to explain the three cost drivers above if a client queries the jump from standard secondary glazing pricing.
Worked example
A client near a busy arterial road wants acoustic secondary glazing fitted to three windows on the road-facing elevation of a 1930s semi, leaving the rest of the property at standard spec (a sensible mixed approach — see acoustic glazing vs secondary glazing comparison for why this is often the right call).
- Survey visit: reveal depth confirmed at 210mm, sufficient for a full 200mm air gap — no charge, absorbed into quote.
- 3 × standard-size acoustic units, 200mm gap, 6.4mm laminated acoustic glass: materials £750 per unit (£2,250 total).
- Sub-frame and specialist compression seals: included in unit materials figure above.
- Fitting labour: 3 units × 75 minutes average = 3.75 hours, one fitter, at a day rate equivalent of roughly £250/day (London/South East rate) = approximately £120.
- Sundries (fixings, trims, making good materials): £60.
- Subtotal (materials + labour + sundries): £2,430.
- Markup at 30%: £729.
- Quoted price, three windows, ex-VAT: £3,159 (approximately £1,053 per window, within the £700–£1,100 standard-size acoustic range once size and glass spec are accounted for).
- Add VAT at 20%: £3,790.80 total client price.
Compare this against quoting the same three windows at standard secondary glazing spec (roughly £250–£600 each per secondary glazing pricing guide) — a client who genuinely needs the acoustic benefit for a road-noise complaint would be poorly served by the cheaper standard quote, and a tradesperson quoting standard-spec pricing for an acoustic-spec job would be running the job at a loss once the laminated glass and deeper sub-frame are actually bought in.
Red flags and what to quote
- Reveal depth insufficient for the full acoustic gap — quote the achievable gap honestly and set noise-reduction expectations accordingly; don't sell the top-end dB figure if the reveal won't deliver it.
- Client conflating acoustic-spec with a thermal upgrade — clarify the acoustic premium buys noise reduction, not meaningfully better U-value; see acoustic glazing vs secondary glazing comparison.
- Whole-house acoustic-spec quote where only one elevation faces the noise source — recommend mixing acoustic-spec on the affected elevation with standard spec elsewhere, both fairer to the client and more competitive against alternative quotes.
- Customer-supplied measurements — never quote bespoke acoustic units off these; survey it yourself, and confirm reveal depth specifically.
- Standard seal substituted to save cost — don't; a standard seal on a laminated acoustic pane will noticeably underperform the dB figures being quoted, and this is the kind of shortcut that generates a complaint and reputational damage on what's meant to be a premium product.
Itemise as: survey (if charged); acoustic units by size, air gap and glass spec; sub-frame and specialist seals; fitting labour; and making good. State the air gap and glass thickness explicitly so the client can see why the price sits above the standard secondary glazing figures they may already have seen.
Frequently Asked Questions
Why is acoustic secondary glazing so much more expensive than standard secondary glazing?
Three specific cost drivers: laminated acoustic glass costs more to manufacture than plain float glass, the wider air gap needed for the acoustic benefit requires a deeper (more material-heavy) sub-frame, and the seals are a specialist, higher-cost component engineered specifically to stop sound leakage that wouldn't matter thermally but would undermine the noise reduction being sold. It isn't a discretionary markup — each element is doing real work toward the dB figure being quoted.
Should I ever quote acoustic-spec at close to standard secondary glazing prices to win a job?
No — this is the fastest way to turn a good job into a loss-making one once you've actually bought laminated glass and a deeper sub-frame. If a client's budget won't stretch to acoustic-spec, the honest answer is to recommend standard secondary glazing rather than acoustic-spec at an unsustainable price — see acoustic glazing vs secondary glazing comparison for when standard spec is genuinely the right, sufficient answer anyway.
How do I justify the jump in price if a client has already seen standard secondary glazing figures elsewhere on this wiki or from a competitor?
Explain the three cost drivers directly: the glass itself, the deeper sub-frame for the wider gap, and the specialist seals — and be specific about the air gap and glass thickness you're quoting versus what a standard unit would offer. Clients with a genuine noise problem generally understand and accept the premium once the reasoning is clear; the risk is only in failing to explain it and leaving the client to assume it's just a bigger number for the same product.
Does a bigger air gap always mean a proportionally bigger price jump?
Not linearly — the biggest jump is from a standard unit (20–100mm gap, float glass) to entry-level acoustic-spec (150mm gap, laminated glass), because that's where the glass type and seal design change. Going from a 150mm to a 200mm acoustic gap adds sub-frame material and depth but doesn't require a different glass or seal category, so the price increase for that step is more modest than the initial jump into acoustic-spec.
Is it ever worth recommending acoustic-spec glazing to only part of a property?
Yes, and it's often the more cost-effective, sensible recommendation — fit acoustic-spec to the elevation actually facing the noise source (road, rail, flight path) and standard secondary glazing spec elsewhere in the property. This delivers the acoustic benefit where it's needed without inflating the whole-house price for windows that don't face the noise problem.
Regulations & Standards
BS 8233 — guidance on sound insulation and noise reduction for buildings; the reference standard when pricing and specifying acoustic performance claims to a client
Building Regulations — secondary glazing exemption — acoustic-spec secondary glazing, like standard secondary glazing, does not trigger the FENSA route or the replacement-window thermal obligations of Approved Document L, because the primary window is retained
FENSA — the competent-person scheme for replacement glazing; does not apply to secondary glazing of either spec
Listed Building Consent / conservation area controls — acoustic-spec secondary glazing is typically treated the same as standard spec for consent purposes, as a reversible internal alteration, but always confirm with the local authority conservation officer on a listed or conservation-area property before proceeding
Approved Document L (conservation of fuel and power) — relevant to general thermal context, though the acoustic premium is not primarily a thermal upgrade
BS 8233 — sound insulation and noise reduction for buildings (BSI) — acoustic performance reference for pricing and specification
FENSA — what is and isn't covered — confirms secondary glazing falls outside replacement-glazing certification
Historic England — secondary glazing in historic buildings — heritage and conservation guidance relevant to acoustic-spec reveal detailing
Approved Document L (GOV.UK) — conservation of fuel and power, thermal context
acoustic glazing vs secondary glazing comparison — the technical comparison covering when acoustic-spec is justified versus standard secondary glazing, the companion decision-making article to this pricing guide
secondary glazing pricing guide — pricing for standard secondary glazing by unit type and glass spec, the baseline this guide's acoustic premium sits above
secondary glazing vs double glazing comparison — the category-level comparison between secondary glazing and full double-glazed replacement
secondary glazing — technical detail on secondary glazing U-values and retrofit options