Retrofitting a period property is a delicate job. You want modern comfort without losing the charm that makes it special.
When it’s done well, a retrofit brings older buildings back to life.
You preserve what matters while making the space warmer, quieter, and more efficient.
At Gowercroft Joinery, we specialise in timber windows and doors for heritage retrofits. From Georgian townhouses to Edwardian terraces, our products are used in listed buildings and conservation areas across the UK.
So how do you upgrade a historic property without compromising its character?
And why are windows and doors such an important part of the process?
What does retrofit mean in a heritage context?
A retrofit upgrades a building without damaging its character. In heritage settings, the aim is to improve energy use and comfort while keeping original features.
This might involve better insulation, ventilation, or glazing. But it must be done carefully and respectfully.
The goal is simple. Keep what makes the building special while making it perform better.
Why are windows so important in a retrofit?
Windows are often the biggest cause of heat loss. They also let in draughts and noise.
In period homes, they’re also a key visual feature.
That’s where things get tricky…you usually can’t replace them with modern-looking designs, especially in listed buildings.
Our Heritage Range solves this. Purpose-built for heritage retrofits, we’ve spent years refining them to meet strict planning rules while delivering modern comfort.
They feature traditional timber profiles, slim vacuum glazing, and concealed balances.
The result is a window that looks authentic and performs brilliantly.
To top it off, the Heritage Range achieves U-values as low as 1.2 W/m²K and is backed by lifecycle data from Derby University.
These range looks traditional, but performs better than the majority modern windows and doors.
How do retrofit windows support sustainability?
Retrofitting reduces waste and helps buildings use less energy.
Windows play a huge role in that.
Our vacuum glazing can cut heat loss by up to 80 percent compared to single glazing.
In one award-winning retrofit, our products helped reduce total energy use by over 80 percent.
We also provide Environmental Product Declarations (EPDs).
These show the full lifecycle impact of each product, including embodied carbon.
It’s more than simply a window upgrade. It’s a low-carbon, future-proof solution.
What planning rules apply to heritage retrofits?
Listed buildings and conservation areas usually need planning consent. Most officers will ask for like-for-like designs (e.g. if it was timber, it should remain so).
That means no uPVC. You’ll also need glazing bars and frame profiles that match the originals.
We’ve worked with conservation teams across the UK. Our drawings and specifications help clients get permission quickly and smoothly.
Need more guidance? See our Guide to Windows for Listed Buildings.
What should you look for in heritage retrofit windows?
Not all timber windows are suitable for listed or historic buildings. Look for these key features:
- Slim glazing profiles that replicate original single glazing
- Timber frames with traditional mouldings that match the period style
- Concealed balances or traditional weights for authentic appearance
- Planning-friendly designs that meet listed building and conservation rules
- Low U-values for modern thermal performance (ideally 1.2 W/m²K or lower)
- Long-lasting finishes such as microporous paint systems that won’t crack or peel
- Evidence of testing and lifecycle data, such as EPDs or university-verified performance reports
- A clear, robust guarantee with no hidden conditions
- Optional servicing and aftercare to support long-term performance
Choosing the right window isn’t just about looks. It’s about combining heritage detailing with modern reliability.
Why choose Gowercroft for your retrofit project?
We don’t just build windows. We help solve complex problems.
We’ve supported some of the UK’s most demanding retrofits, including:
- Mews House, winner of the AJ Retrofit and RIBA awards
- Waterman Building, where our windows helped offset carbon within six years
- Saltdean Lido, a full restoration of a coastal Art Deco landmark
Our products last over 50 years with minimal upkeep. Our 10 year guarantee is clear, with no loopholes. And our optional Timbacare service extends the lifespan even further.
Ready to begin your heritage retrofit
Whether you’re doing a deep retrofit or a gradual upgrade, we’re ready to help.
We offer expert advice and support from design to installation.
📧 Email us: info@gowercroft.co.uk
📞 Call: 01773 300510