Dalton Joinery
Double Glazed Window Units
Energy-efficient double glazed timber windows
Modern double-glazed units built into traditionally proportioned timber windows. The best of both worlds — period look, contemporary thermal performance — without resorting to uPVC. Argon-filled, soft-coat low-E sealed units sit in solid timber sashes with authentic external detailing.
Benefits
Why choose Double Glazed Window Units
- U-values from 1.4 W/m²K on standard 24mm units
- Argon-filled, soft-coat low-E coatings
- A-rated thermal performance achievable
- Built into period-correct timber sections
- Acoustic laminated option for road-facing rooms
- Toughened safety glass on low-level lights
Features
Engineered for performance
- 24mm argon-filled sealed units as standard
- Internal beading for security
- 10-year sealed-unit warranty
- Optional warm-edge spacers for condensation control
Make it yours
Configurator
Mix and match colours, hardware and glass to suit your home.
Colours
Available finishes
White
Off-white / Cream
Heritage Grey
Graphite
French Navy
Sage Green
Chartwell Green
Bespoke RAL match
Hand-applied wax
Danish oil
Hard-wax oil
Satin lacquer
Matt lacquer
Frame styles
Choose your style
- Casement
- Sash
- Fixed light
- Bay
- Custom shape
Glass
Glass options
- Single glazed — heritage matched to existing
- Slim double glazed units (12–14mm) for conservation areas
- Standard 24mm argon-filled double glazing
- Triple glazing for extreme exposure or noise
- Acoustic laminated for road-facing rooms
- Toughened safety glass (BS EN 12150)
- Obscure / privacy patterns
- Stained, leaded and Georgian bar details
Hardware
Furniture & hardware
- Solid brass, chrome, satin or bronze ironmongery
- Espagnolette and shootbolt locking
- Heritage monkey-tail and pear-drop handles
- Period-correct fanlight catches and stays
- Sash pulleys, lifts and sash locks (for sash windows)
- Multi-point security locking on opening lights
- Trickle vents where Building Regulations require
Ideal for
Property suitability
New-builds, unlisted period properties, conservation areas where slim DG units are approved, and any project where heat loss and energy bills are a priority.
Installation
How we fit it
Identical to our standard window installation — surveyed, manufactured, finished and installed in-house.
Common questions
Frequently asked
How long does it take from first call to installation? +
A typical project takes 6–12 weeks from initial site visit to install. Survey and design happen in week 1; manufacture in our workshop takes the bulk of the time; installation is usually a few days on site. Larger projects or specialist timber may take longer — we'll be honest about timings at the quote stage.
Do you do free quotes? +
Yes. We'll come out, talk through your project, take measurements and provide a written itemised quote. There's no obligation, no high-pressure follow-up and no fee.
Do you install everything yourselves? +
Yes. Everything we make is fitted by our own team. For kitchens and bedrooms we also coordinate any plumbing, electrical or building work on your behalf so you have a single point of contact.
Where are you based and how far do you travel? +
Our workshop is at Seal Croft Farm in Seal, just outside Sevenoaks. We cover Sevenoaks, Tunbridge Wells, Tonbridge, Maidstone, Bromley, Orpington and much of central and south London. For larger projects we travel further into Kent and Surrey.
Explore the range
More Bespoke Windows
Like the Double Glazed Window Units? Let's talk.
Free site visits across Kent and London — get in touch to discuss your project.