Regulations and Guidelines for Installing Heritage Windows
Our advice is to always check with your local authority if you are any sure about the replacement of old windows or the building of a new window opening. However, the below is intended to help you by way of general advice but do always check.
Do You Need Permission to Replace Your Windows?
If you're replacing existing windows with ones that look broadly the same, you may not need planning permission. Most houses benefit from Permitted Development (PD) rights, which usually allow like-for-like replacements without formal approval—especially if the new windows match the originals in style, size, material appearance, and colour.
That means switching from timber to timber-look uPVC, for example, is often acceptable—so long as the visual impact remains in keeping with the home.
However, flats and maisonettes don’t benefit from the same PD rights, and if you're in a leasehold property, you'll also need permission from the freeholder, even for simple replacements.
Homes in Conservation Areas or Listed Buildings
If your property is Listed, in a Conservation Area or Located in a National Park or Area of Outstanding Natural Beauty (AONB) you will almost certainly need formal consent.
New Window Openings
Adding a new window may fall under Permitted Development, but it depends on where it is, how it looks, and whether it faces the street. New rear or side-facing openings are often easier to approve.
However, any new window at the front of your property, especially if it alters the overall appearance or layout, is more likely to require full planning permission. Always check with your Local Authority Planning Department first.
Bay Windows
If you're upgrading existing bay windows, that generally counts as a straightforward replacement and doesn’t require planning permission.
But if you’re adding a new bay window, it’s treated as a small extension—which means you will need planning consent, particularly if it’s on the front of your home.
Rear or side-facing bays may offer more flexibility but still need to comply with PD limitations.
Unusual Window Designs or Layouts
Thinking about changing window shapes, adding larger glazed areas, or choosing an unusual colour? Significant changes to the layout, size, or appearance of windows are more likely to need approval—especially on the front or side elevations.
Side-Facing Windows and Privacy Rules
You can usually fit a window on a side elevation under PD, but there are strict privacy rules for upper floors:
• Any upper-floor side window must be fitted with obscure glazing.
• It must also be non-opening if the lower edge is less than 1.7 metres from the internal floor level.
These rules are designed to protect neighbouring properties and will apply regardless of window style.
Maintenance Tips for Long-Lasting Heritage Windows
To keep your windows performing well, routine cleaning is one of the best things you can do. Cleaning allows the foils, coatings and paint finishes to be clean of airborne contaminants. At the same time, cleaning allows you to spot any damage which may need quick repair, especially on timber windows. uPVC windows don’t have this issue and a wipe with warm soapy water is usually enough.
Modern heritage windows are designed for longevity and ease of maintenance, especially those in uPVC timber-look materials. If you are not sure on any issues relating to your windows, contact the manufacturer or the installation company.
Choosing the Right Heritage Window Supplier
Not all heritage windows are the same—and neither are the companies that supply them. Choosing the right supplier is just as important as choosing the right product. You want a company that understands period properties, conservation requirements, and how to deliver a traditional look without compromising on quality or performance.
Here’s what to look for in your potential supplier:
- Specialist knowledge in timber-look or traditional window design—not just of their product, but others available on the market to compare.
- A strong track record of installations using this window style.
- Understanding what authentic detailing actually means. For example, accurate proportions, mechanically jointed frames, woodgrain finishes, traditional hardware, and accurate glazing bar layouts.
- Product consistency, especially if you’re ordering windows in multiple phases.
- Matching doors and sidelights, where needed, to create a matching look in your home.
We were the first to bring a true timber-alternative window to market in the UK, and we’ve continued to refine our products with unique features you won’t find anywhere else. Every window is made to order, crafted to suit the property, and supplied through trusted professionals who know how to get the installation right.
Always ask to see product samples, recent installations, or visit a showroom where you can see the finish and detailing up close. It’s the easiest way to know if what you’re buying is genuinely heritage in style—or just a standard window with a few cosmetic tweaks.
When researching heritage window suppliers, always prefer those with a proven track record. Check out their reviews, their case studies, their overall product knowledge and their expertise working on projects in Conservation Areas.
Real-Life Transformations with Heritage Windows
We’ve helped thousands of homeowners over many years transform their properties:
- Replacing outdated or failing timber windows in listed homes
- Improving insulation and security without losing period charm
- Enhancing kerb appeal and property value in sought-after areas
- Our projects area details just some of the work completed using our expertly crafted and unique Evolution Heritage Windows.
Future Trends in Heritage Windows
Heritage window design continues to evolve. With all of us aware or rising energy costs, thermal performance is now high on the list when choosing heritage windows and triple glazing is being used more.
Window colours are of course another consideration, whether it’s a classic shade or to match Farrow and Ball and Cotswold colours. Sustainability is also becoming important to homeowners. That is why uPVC is recyclable and chosen right, environmentally aware too.
It is inevitable that regulations will tighten across thermal performance, overheating in homes, security and environmental credentials. Heritage-style products will keep up with expectations and we continue to invest in product development to lead this market as we have as the original inventors of the heritage window in premium uPVC.
Frequently Asked Questions about Timber Windows
Q. Can you replace heritage windows?
A. Yes, provided you meet planning or listed building requirements. Our windows have been approved in conservation areas and those with planning limitations
Q. Who makes the best uPVC windows in the UK?
A. There are many heritage window brands to choose from, but Evolution pioneered the timber-alternative category and remains one of the most respected for authentic heritage styling and unique features not possible or available with other brands.
Q. What is a heritage window?
A. A window that replicates the appearance of original period designs and understands the features of older windows in its design.
Q. How much should I budget for new windows in the UK?
A. Costs vary based on style, size, and features. Heritage windows are generally more detailed and bespoke, so expect to invest more than for standard uPVC casement windows. Contact us for advice.
Q. Do you offer fitting? Yes—we work with a nationwide network of expert installers, fully trained in fitting our bespoke and highly-engineered windows.
Q. How long does delivery take? Lead times vary depending on specification and colour. We'll confirm timings when you request a quote.
Q. Can I order online or by phone? We recommend starting with an enquiry—one of our team will guide you through the options and arrange a call with your nearest Evolution specialist showroom.