Sash · Casement · Low-E, argon & warm-edge as standard
Double Glazed Timber Windows
Every wooden window we make is double glazed as standard — low-E glass, argon fill and warm-edge spacers, achieving a U-value of 1.4 W/m²K. Choose double glazed sash or casement windows in engineered pine, meranti or solid oak, made to measure and part of our range of bespoke timber windows.
From £449+VAT
Double glazed as standard
U-value 1.4 W/m²K
Low-E + argon included
Acoustic & triple options
5-year warranty
The basics
Double Glazed Wooden Windows, Made to Measure
Timber and double glazing are a natural pairing: wood is a far better insulator than aluminium, and a well-made timber frame keeps its seals tight for decades. All our windows — engineered pine, engineered meranti and solid oak — come double glazed as standard, so there is no upgrade to pay for to get a warm, quiet window.
Standard units achieve a whole-window U-value of 1.4 W/m²K, meeting Part L of the Building Regulations for replacement windows. Windows are made to your measurements, factory finished in any RAL or Farrow & Ball colour and delivered anywhere in the UK — we are supply only, so your own joiner or builder fits them.
Inside the unit
What’s Inside Our Double Glazed Units
| Component | Our standard | Why it matters |
|---|---|---|
| Glass | Low-E coated glass | The invisible coating reflects room heat back inside while letting light through — the biggest single gain in insulation |
| Cavity fill | Argon gas | Denser than air and conducts about a third less heat; inert and colourless |
| Spacer bar | Warm-edge composite, not aluminium | Cuts the cold bridge at the glass edge, reducing the misty condensation ring seen on older units |
| Unit thickness | 14–24mm, matched to the profile | Full-thickness units in casements; slimmer units where solid glazing bars or heritage sash sections need them |
| Whole-window U-value | 1.4 W/m²K | Meets Part L for replacement windows |
Warm-edge spacers alone improve the overall window U-value by around 0.1–0.2 W/m²K — small per window, but it adds up across a whole house. For U-values, Part L and running-cost savings in more depth, see our energy efficient timber windows guide.
Glazing options
Double Glazing Options for Timber Windows
| Option | What it does | Price guide |
|---|---|---|
| Standard double glazing | Low-E glass, argon and warm-edge spacers, U-value 1.4 W/m²K | Included |
| Acoustic laminated glass | Laminated pane with a sound-damping interlayer for roads, railways and flight paths | About £100–150 per window |
| Slim units with solid bars | Each small pane separately sealed for authentic Georgian and heritage looks, around 1.6–1.8 W/m²K | Solid bars about £100–200 per window |
| Triple glazing | Third pane and second cavity, around 0.8–1.0 W/m²K, about 50% heavier | Typically 25–35% more per window |
Our honest take: for most UK homes, our standard double glazing is the sweet spot. Triple glazing earns its keep in new builds designed to Passivhaus or near-Passivhaus standards, or in genuinely exposed locations. If your house has uninsulated solid walls, the triple-glazing premium will usually save more heat spent on wall insulation instead. For exposed sites, see our weather-resistant timber windows.
Noise
Noise Reduction with Double Glazed Wooden Windows
Double glazing is usually bought to keep heat in, but if you live near a busy road, a railway or under a flight path, the acoustic benefit may matter more day to day. A standard double glazed unit typically reduces outside noise by around 29–31 dB. Since a 10 dB drop sounds roughly half as loud, that takes a busy road from conversation-disrupting to a background hum.
For serious noise, choose acoustic laminated glass: a sound-damping interlayer bonded between two panes absorbs vibration far better than an air gap, and typical acoustic configurations reach around 35–38 dB. Using different glass thicknesses on the inner and outer panes helps too, because they resonate at different frequencies. More in our guide to acoustic windows.
Sash windows
Double Glazed Sash Windows
Sash windows and double glazing have a complicated history. A sealed unit is heavier than single glass, so the sash needs heavier counterweights — get it wrong and the window slams shut or will not stay open. Our sash windows on weights are individually balanced: each sash is weighed after glazing and its weights are matched to it, so it stays put wherever you leave it.
Spring-balanced sashes follow the same principle, with spiral balances specified for the exact sash weight at the factory, so your installer is not adjusting them on site. Double glazed timber sash windows start from £449+VAT on weights or springs, and from £649+VAT for Georgian sashes on weights. (In North America the same style is called a double-hung window.)
Casement windows
Double Glazed Casement Windows
Casements are more forgiving: there is no counterbalance, the sash simply hinges open. Our flush casement range takes a full double glazed unit without compromising the profile, and the sash closes flush with the frame for a clean traditional line that suits anything from a 1930s semi to a barn conversion.
Side-hung, top-hung or a fixed lower panel with an opening top light all take the same glazing. For Georgian windows we can divide the glass with solid through-bars, with each small pane separately sealed, or use duplex or applied bars over a single unit. Double glazed flush casements start from £449+VAT for a single casement and £599+VAT for a double.
Frame timber
Pine, Meranti or Oak Double Glazed Windows
| Timber | Construction | Typical service life | Price guide |
|---|---|---|---|
| Engineered pine | 3-layer engineered softwood | 25–35 years | From £449+VAT |
| Engineered meranti | 3-layer engineered hardwood | 35–45 years | About 20–30% more than pine |
| Solid European oak | Solid timber throughout | Around 50 years | From £799+VAT |
All three take the same double glazing specification. Compare them in detail in our hardwood windows, softwood windows and oak windows guides.
Costs
Double Glazed Timber Windows Prices
| Window | Price from (+VAT) |
|---|---|
| Sash window on weights | £449 |
| Sash window on springs | £449 |
| Georgian sash on weights | £649 |
| Georgian sash on springs | £699 |
| Flush casement — single | £449 |
| Flush casement — double | £599 |
| Georgian flush casement — triple | £799 |
All prices include double glazing with low-E glass and argon. Prices exclude VAT and installation. Delivery is typically £80–120 within 50 miles of our manufacturing base and £200–350 for the Scottish Highlands and other remote areas. Full details on our timber windows prices page.
How it works
Ordering Double Glazed Wooden Windows
2
Quote in 48h
Choose style, timber, glazing and colour and we’ll send a detailed quote within 48 hours.
3
Made to order
Confirm with a 50% deposit. Windows are made in about 20 working days.
4
UK delivery
Pay the balance on delivery. Your joiner or builder fits them — we are supply only.
Our Best-Selling Timber Windows:
Double Glazed Timber Windows FAQ
Are your timber windows double glazed as standard?
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Yes. Every window we make is double glazed as standard with low-E glass, argon fill and warm-edge spacers, achieving a whole-window U-value of 1.4 W/m²K.
How much do double glazed wooden windows cost?
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Double glazed timber sash and casement windows start from £449+VAT in engineered pine, Georgian sashes from £649+VAT and solid oak from £799+VAT. Send your sizes for an exact quote within 48 hours.
Can sash windows be double glazed?
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Yes. Our double glazed sash windows are balanced for the extra weight of the sealed units — weights are matched to each glazed sash, or spiral balances are specified for its exact weight — so the sashes stay where you leave them.
Is low-E glass included?
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Yes. Low-E glass, argon and warm-edge spacers are all part of our standard double glazing, not paid upgrades.
Is triple glazing worth it for timber windows?
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For most UK homes, no — our standard double glazing is the sweet spot. Triple glazing typically adds 25–35% per window and about 50% more weight, and pays off mainly in Passivhaus-style new builds or very exposed locations.
Do double glazed wooden windows reduce noise?
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Yes. Standard units typically cut outside noise by around 29–31 dB, and acoustic laminated glass (about £100–150 per window) reaches around 35–38 dB.
Do you install double glazed timber windows?
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No. We are supply only: we manufacture, glaze, finish and deliver UK-wide, and your own joiner or builder fits the windows.
Get a Quote for Double Glazed Timber Windows
Send your window sizes, style and any glazing needs — acoustic, triple or Georgian bars — and we’ll quote within 48 hours.
