Alitherm Heritage Windows: The Perfect Upgrade For Period and Character Homes

• January 7, 2026
• General

When it comes to refurbishing a period property, finding windows that satisfy both planning requirements and modern performance standards can feel like an impossible task.

Smart Alitherm Heritage windows meet the needs of period property renovations perfectly. Designed specifically for heritage applications, this range delivers the signature slim sightlines and aesthetic appeal of traditional steel windows at a lower cost. Whether you’re working on a Victorian terrace, an Art Deco conversion, or a listed building renovation, Alitherm Heritage provides a modern solution without compromising on period charm.

At Lightfoot Windows, we’ve supplied and installed Alitherm Heritage windows across countless projects throughout the UK. This guide explains why they’re the perfect choice for character homes, and what you need to know before committing to your upgrade.

Benefits of Alitherm Heritage

The Alitherm Heritage range was developed specifically to meet the needs of building renovations in sensitive planning areas. Unlike standard modern aluminium windows, every element has been engineered to replicate the proportions and appearance of traditional steel doors and windows.

Key benefits include:

• The system has secured planning approval in many conservation areas
• Slim profiles match the sight lines of original historic designs, making them ideal for listed buildings and heritage projects
• Thermal break technology deliver excellent insulation
• Aluminium requires minimal upkeep – a simple wipe with a damp cloth keeps them looking pristine
• Available as fixed windows, casement windows, top hung windows, tilt turn, and pivot configurations
• Dual colour options – Different finishes inside and out

The range of windows can be built as a series of horizontal modules, which stack using horizontal couplers to form multi-part designs. This modular approach replicates traditional proportions whilst offering complete design freedom for both new build and renovation projects.

Understanding U-values and energy efficiency

One of the most compelling reasons to choose Alitherm Heritage windows is their outstanding thermal performance. Historic window designs often allow heat loss in winter and creating cold spots where warm air meets cold surfaces, leading to condensation and damp. Replacing original windows with Alitherm Heritage windows can make a significant difference to the thermal efficiency of your property.

Alitherm Heritage delivers an overall U-value of 1.6 W/m²K when installed with appropriate double glazing. This  represents excellent thermal transmittance, helping to:

• Reduce heating bills by minimising heat loss
• Prevent condensation and associated damp issues
• Improve comfort by eliminating cold draughts
• Meet building regulations for replacement windows
• Achieve a ‘B’ window energy rating as standard

The secret lies in the thermal break technology. This system creates a barrier between the internal and external faces of the aluminium frames, preventing cold air from conducting through to the warm interior. Unlike historic single-pane steel designs, this thermal break ensures optimum thermal performance without compromising the slim aesthetic.

Approved for conservation areas and listed buildings

Alitherm Heritage has become the go-to specification for architects and designers working on sensitive heritage projects. The system’s ability to satisfy strict planning requirements whilst delivering modern performance makes it an ideal solution for:

• Listed building renovations where like-for-like replacement is required
• Conservation area properties where planning officers scrutinise window proposals
• Period homes including Victorian, Edwardian, and Art Deco styles
• Large-scale refurbishment projects
• Commercial applications in historic buildings

The signature slim sightlines are what set this range apart. Traditional steel windows are characterised by their slender frames and large glass areas – a look that’s impossible to achieve with standard aluminium profiles. Alitherm Heritage replicates these proportions precisely, creating an authentic appearance that satisfies even the most demanding planning authorities.

Colour, style and hardware choices

Every period property is unique, which is why the Alitherm Heritage range offers extensive customisation to match your specific needs.

Colour finishes

The system is available in either single or dual colour polyester powder coat finishes to British Standard quality. Popular choices include:

• Classic black to replicate traditional steel frames
• Heritage greens and greys for rural properties
• Custom RAL colours to match existing joinery

Dual colour options are particularly useful for listed buildings, allowing you to satisfy planning requirements with a heritage finish externally whilst choosing a modern look inside that coordinates with your interior scheme.

 Window configurations

The range includes virtually every traditional window style:

• Fixed pane windows for maximum light
• Side-hung casement windows for ventilation
• Top-hung designs for safe airflow
• Tilt and turn for easy cleaning
• Pivot windows for a contemporary twist

These can be combined within the same frame using horizontal modules to recreate traditional multi-light designs. A specially designed drip bar between modules ensures weather-tightness whilst maintaining authentic proportions.

Hardware options

A full suite of hardware options allows you to specify traditional detailing including monkey tail stays, period latches, and heritage handles. Modern functionality sits behind traditional aesthetics, giving you the best of both worlds.

Glazing choices

While the system is designed for double glazing, numerous glass options are available including:

• Low-E coatings for improved thermal efficiency
• Acoustic glass for noise reduction
• Toughened safety glass where required by building regulations
• Georgian bars or astragal grids for divided-light appearance

Our team can advise on the best glazing specification to meet your project’s specific requirements.

Why choose Lightfoot Windows for your Alitherm Heritage installation

At Lightfoot Windows, we provide an installation service for the Alitherm Heritage range. Our team understands the unique challenges of working on traditional properties, from liaising with conservation officers to ensuring installations meet current building regulations.

We’ve built our reputation on delivering quality workmanship and honest advice. Whether you’re restoring a Victorian townhouse or upgrading a 1930s semi, we’ll help you choose the ideal solution from the Alitherm Heritage range.

Transform period properties with confidence: contact Lightfoot today

Alitherm Heritage windows represent the perfect balance between heritage authenticity and modern performance. Their proven track record in sensitive planning areas, combined with superior thermal efficiency and minimal maintenance requirements, makes them an excellent investment for any character property.

Get in touch today to arrange your free, no-obligation quote. Complete our online contact form, call us on 020 8662 9090 for email general@lightfootwindows.co.uk.

Want a quick estimate? Visit our ‘Get An Estimate‘ page and fill out the required information. One of our friendly experts will get back to you within 48 hours with an indicative cost.