Can You Install Double Glazing On A Listed Building? Written by Tom Gill Updated on 26 January 2023 Energy bills are soaring, making insulating your home more important than ever. Double glazing costs a lot, but it's one of the most effective and popular energy-saving methods around.Getting double glazing for your home isn’t a uniform process though, as there are different rules depending on what type of property you have.We’ve looked into whether you can install double glazing on a listed building, how you can apply for planning permission, and what impact it could have on your home’s value.Want to skip the reading and find quotes for double glazing? You can fill in our simple form here and we’ll put you in touch with our trusted suppliers. They’ll get back to you with bespoke double glazing quotes for you to compare. What type of double glazing do you need? Aluminium frame uPVC frame Wooden frame Other / not sure Get started What's on this page? 01 Is double glazing allowed on listed buildings? 02 How to apply for planning permission for double glazing 03 Does double glazing on a listed building cost extra? 04 Will double glazing improve the value of your listed building? 05 What are the downsides of installing double glazing on a listed building? 06 Things to consider before installing double glazing on your listed building 07 Summary Is double glazing allowed on listed buildings?You can install double glazing on a listed building, but it is not as simple as it would be in other properties.That’s because listed buildings are protected for their historical significance, beauty, or both. Double glazing often costs more for listed buildings because they typically have timber or stone window frames that make installing modern uPVC double glazing impossible.Planning authorities such as English Heritage will seek to stop changes to a listed building’s key features, including most forms of double glazing.This is a problem for homeowners living in a listed building because the windows are often thin and poor at keeping warmth inside. Their level of sound insulation is often bad too.Even if you choose double glazing with a wood finish frame – for example – it’s likely heritage groups will still look to block planning permission.There are options though, such as secondary glazing. This is where a second pane of glass is installed behind an existing window, without any need to replace or alter the frames.And when it comes to replacing it, you can remove the secondary glazing discreetly, as it’s typically not attached to a frame. What about Grade I listed buildings?The same rules for double glazing apply to Grade I listed buildings: no uPVC double glazing, no other modern window types, and nothing that impacts the property’s window frames.Grade I listed buildings are even rarer than Grade II — just 9,797 exist in the UK — meaning you must carry out any alterations with careful consideration.Historic England makes it clear that secondary glazing is the most acceptable option, explaining: “Secondary glazing when carefully designed and installed allows the original windows to be retained unaltered, and where necessary repaired, whilst reducing air leakage and conducted heat losses.“As a result, there is no loss of historic fabric, and in most cases the installation is easily reversible.” How to apply for planning permission for double glazingPlanning permission for historic buildings is called Listed Building Consent, and you must apply for it before making any alterations, including secondary glazing.Failing to do so is a criminal offence.You will need to apply for planning permission if:You’re replacing the windows with a new style of windowThere is a change to the materials used for the framesThere is a change in the type of glazing, e.g. single glazing to double glazingYou’re repainting existing windows a different colourYou’re proposing to re-glaze, involving the loss of original glassHere’s how to apply for Listed Building Consent:Contact your Local Planning Authority — each council website will have a section dedicated to planning permission, where you can fill in your property details and will be put in touch with a conservation officer, or can download an application form to fill inDiscuss your options — your conservation officer will assess the property’s listed status, what the current window situation is, and what you’ll likely be allowed to doWait for confirmation — the planning authority will give attention to the desirability of protecting your property, its setting, and the features that make it special. The risk of damage is too high in some cases, so prepare for rejectionIf you succeed in your application, you’ll be granted planning permission and told what type of window modifications you can make. What type of double glazing do you need? Aluminium frame uPVC frame Wooden frame Other / not sure Get started Does double glazing on a listed building cost extra?Yes, double glazing in listed buildings costs more because standard double-glazed windows aren’t normally accepted. Owners usually turn to slim-profile double glazing instead, as it fits better with traditional window styles.Unfortunately, slim-profile glazing is more expensive than standard double glazing, and less thermally efficient.This makes secondary glazing more appealing for listed building owners. Not only does secondary glazing cost less, but in some cases it’s better at insulating than ordinary double glazing.However, standard double glazing can be easily used in extensions or conversions, as long as they’ve been approved for Listed Building Consent. Extensions are typically built using modern materials, so it makes sense to get the most efficient glazing. Will double glazing improve the value of your listed building?Getting any energy efficiency measures will improve the value of your home, and double glazing on a listed building is no different.Double glazing adds 10% to the selling price of the average UK property, so there’s every chance you’ll benefit.You should definitely get double or secondary glazing if you can, both for the way it improves homes’ values, and its excellent energy saving benefits.Opting for Georgian windows, or another type that matches the era your building was built in will also ensure the aesthetic remains unchanged. What are the downsides of installing double glazing on a listed building?You’ll save on your energy bills and keep your home warmer with double glazing, but there are some downsides. Here are the main cons of installing double glazing on a listed building:You can damage its heritage — even if you have planning permission, double glazing can still damage the original building materials if installed poorly. Older materials like timber or stone are unpredictable when tampered with, so there’s always an added riskBetter insulation can cause issues — double glazing is designed to keep heat in, but in older buildings this can lead to excess condensation. If moisture levels get too high, wooden frames may start to rot and mould/mildew can build up on stone. Slim-profile double glazing, which is typically preferred over standard double glazing in listed buildings, has a higher chance of misting and condensation. Things to consider before installing double glazing on your listed buildingCheck if you need planning permission — in most cases you will need to get permission to install double glazing on a listed building. Regulations for secondary glazing are less strict than ordinary double glazing.Find frames that match the building’s aesthetics — it’s important to make sure your new double glazing doesn’t change the look of the original window too much, if at all. Most heritage groups won’t accept imitation frames, such as those with a wood effect, so you’ll either have to match the material or use a transparent frame.Consider the type of glass used — modern glass is uniformly flat, which can have an impact on reflections and make it stand out against older glass. Older windows have imperfections and dimples that heritage groups see as giving them character. Many secondary glazing companies offer anti-glare windows that can minimise this problem. You can also find windows with intentional flaws that blend in seamlessly. SummaryListed buildings are essential parts of the UK’s heritage and should be protected, but so too should the environment.That makes finding a balance between the two important, but thankfully double or secondary glazing can often be installed without damaging a property.If you’d like to find quotes for double glazing, why not fill in our simple form? All you need to do is enter a few details and we’ll pass them to our trusted suppliers. They’ll get back to you with double glazing quotes for you to compare. Written by: Tom Gill Writer Tom joined The Eco Experts over a year ago and has since covered the carbon footprint of the Roman Empire, profiled the world’s largest solar farms, and investigated what a 100% renewable UK would look like. Tom has a particular interest in the global energy market and how it works, including the ongoing semiconductor shortage, the future of hydrogen, and Cornwall's growing lithium industry.