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Conservation Windows
for London Period Homes
Conservation windows should look right from the street — but feel like a genuine upgrade from the inside.
Authentic Replacement Windows for London Conservation Areas
In London's conservation areas, your choice of window is the difference between architectural restoration and a costly planning compromise. We specialise in the exact nuances that planners and homeowners value most.
Standard replacements often fail because they ignore the critical specifics: narrow sightlines, authentic frame depth, and hand-applied putty lines. We provide a straightforward route to compliance by guiding you to the correct architectural specification from day one.
Exact Architectural Matching
We replicate your original window profiles precisely—including frame depth and sightlines—to ensure a seamless transition.
Planning-Ready Specs
Every window we build comes with the technical documentation needed to satisfy local Conservation Officers and Article 4 rules.
Hidden Thermal Performance
Benefit from high-performance double glazing that is virtually indistinguishable from original single-pane glass.
Clean Heritage Installation
Our installers are specialists in period properties, ensuring a clean finish that respects your home's historic fabric.
We Navigate Article 4
So You Don't Have To
Most London homeowners fear that improving comfort means losing their property\'s heritage status. We specialise in visual replacements that satisfy strict council requirements while drastically reducing heat loss.
Article 4 Compliance
If your street has an Article 4 Direction, you need a visual match. We produce the specific "like-for-like" designs that Planners require.
Listed Building Support
Listed buildings require the highest level of detail. We provide the cross-sectional drawings needed for your heritage applications.
Material Authenticity
Conservation officers focus on material integrity. We use premium hardwoods and traditional finishes that meet their strict criteria.
Guaranteed Compliance
We provide the cross-sectional drawings and material specifications that Heritage Officers require to grant approval.
Enjoy a 40% Warmer Home Without Changing Your View
The bulkiness of standard double glazing is what triggers planning rejections. Our range uses ultra-slim thermal units and hand-applied putty-line finishes to achieve a profile identical to single glazing.
Invisible Performance:
- Elite Heat Retention
Modern vacuum-sealed technology hidden behind original sightlines.
- Silence Your Street
Specialised acoustic-laminated glass options for London living.
- Zero Visual Compromise
Lower energy bills without losing your property\'s heritage status.
We help you choose the thermal route that improves your comfort while adding significant value to your property.
Architectural Excellence
Bespoke window solutions designed specifically for London\'s heritage market.
Hardwood Conservation
The definitive choice for high-value period homes. Handcrafted from sustainable hardwoods that are engineered to never warp, twist, or stick.
- Engineered multi-layer timber
- Authentic putty-line profiles
- Advanced weather sealing
Heritage Sash Windows
The classic London look, rebuilt for the 21st century. Replicates original weight-balanced operation with modern, whisper-quiet performance.
- Ultra-slim 20mm sightlines
- Authentic internal beading
- Modern draught-proofing
Heritage uPVC
The low-maintenance alternative. Features mechanical timber-style joints that are designed to satisfy non-listed conservation requirements.
- Mechanical 90° joints
- Authentic woodgrain textures
- Superior A-rated insulation
Secondary Glazing
Perfect for listed properties where the exterior cannot be modified. Provides a massive boost in warmth and noise reduction.
- Invisible from the street
- Up to 45dB noise reduction
- No planning permission needed
Why Harrington's Conservation Windows are the UK's Choice
True conservation windows are defined by the subtle architectural nuances that councils and homeowners notice first.
Planning-Ready Sightlines
Replicating the narrow, elegant profiles of historic timber frames to avoid the bulky appearance of standard modern replacements.
Authentic Glazing Bars
True putty-line profiles and era-accurate layouts that ensure the window respects the original architectural period.
Period Ironmongery
From traditional monkey-tail handles to period-correct hardware, every detail is chosen to match the building's character.
Bespoke Era-Matching
Built to the exacting proportions of Victorian, Georgian, or Edwardian architecture for a seamless integration.
Architectural Finishes
High-grade microporous paints and woodgrain options that protect the timber while allowing it to breathe naturally.
A Natural Result
A window that looks "right" on the elevation—improving performance without ever looking obviously new or out of place.
Expert Guidance
A structured, planning-friendly experience from initial audit to final sign-off.
Architectural Assessment
Our specialists visit your home to document the specific profiles, glazing bars, and era-details of your existing windows.
Technical Specification
We produce detailed CAD drawings and material specifications that are ready to be submitted for planning or landlord approval.
Planning Liaison
We provide the documentation and support needed to guide your application through Article 4 or Listed Building controls.
Bespoke Manufacture
Your windows are built to order using traditional joinery methods paired with modern vacuum-sealed thermal technology.
Specialist Installation
Our team fits your new windows with minimal disruption, activating your comprehensive 10-year guarantee upon sign-off.
Protect your property's
value and character
Do not risk your home's heritage status or a planning enforcement notice. Speak with a specialist who understands the nuances of London's architectural history.
Customer Testimonials
What our clients say about their conservation window projects
"The conservation windows look absolutely authentic. You cannot tell they are double glazed from the street, but the difference in warmth is incredible."
Eleanor T
Islington
"Harrington Windows handled the planning application details perfectly. The new sash windows match the originals exactly."
Richard B
Kensington
"We were worried about changing windows in a conservation area, but the team guided us through every step. The result is stunning."
Sophie L
Greenwich
Frequently Asked Questions
Expert guidance on London conservation requirements
Still have questions?
Our specialists are here to help you navigate London's architectural history.