Replacing Windows in Listed Buildings and Conservation Areas

Thu 01 Oct 2015

If you live in a listed building or conservation area, you’re a lucky person – apart from living somewhere lovely, your home will be worth a bit more too. It may not feel like that when it comes to trying to make improvements, of course. Dealing with conservation officers and your local councils can be a frustrating experience, not least because you are entering a land where the rules can differ depending on specific local guidance.

Here are my top ten tips to help you navigate these murky waters:

1. If you live in a listed building or in a conservation area subject to ‘Article 4 Directions’, you may need planning permission to replace windows and doors. Check with your council before you start work.

2. It’s best to work closely with your conservation or planning officer. Respect his or her point of view; ask for opinions; offer to bring window samples, technical specifications or brochures along. Remember, the conservation officer may not even be aware of the wide range of suitable products on the market.

3. You may not need to replace the windows and doors. You could look at repair options and consider energy-efficiency measures such as draught-proofing, shutters or heavy curtains (not so good in the day time!), or secondary glazing.

4. If you live in a fine, listed building, particularly in a terrace that relies on a consistent visual look, your conservation officer may feel it’s important to keep the look of your current single-glazed window, with the character of the old, imperfect, glass. If your windows are beyond repair, they can be replaced with like-for-like windows, even using special glass and putty etc.

5. For some conservation areas and many listed buildings, a well-designed double-glazed replacement will provide an acceptable compromise between authenticity and modern energy performance.

6. The conservation officer will typically request that you replace like for like. However, if you are replacing replacements and want to return windows back to the original style, take some photos of similar houses in your street or area that still have their original windows so you can show the conservation officer what you think the style should be. Notice the number of panes, the width of glazing bars, the design of any horns. Discuss the design and performance requirements with them. 

7. Modern timber windows – even sliding sashes - can achieve ‘A’ energy ratings, or whole window u-values as low as 1.4W/m2K, with authentic design details, such as slim glazing bars, correct mouldings and a variety of horn designs. Fully factory finished windows are supplied complete from the manufacturer and will have been made under a strict factory production control system to ensure consistent quality, a long life and long maintenance intervals. Make sure you choose fully factory-finished windows. 

8. Your conservation officer may ask you to fit single-glazed windows. However single glazing is not as energy efficient as modern double-glazed period windows. Discuss your need for energy savings, send them photos of the windows you want to install and offer to show them samples. Discuss with your window supplier, who may have had some experience of similar cases. Unless you live in quite a special building, you may be able to fit good double-glazed period windows.

9. If your conservation officer suggests you use narrow cavity double-glazing, discuss the alternatives. It can be expensive, less energy-efficient than standard double-glazing, and may  have a shorter service life. Refer to WWA Narrow Cavity Advice Note.


Take a look at the Conservation area windows page of the Wood Window Alliance website, where there are case studies, lots of information and a listing of members who can supply period windows.

Hannah MansellBritish Woodworking Federation