Leaded windows that are single-glazed, with lead on both the outside and inside of the glass panes, can now be retrofitted with double glazing without the need to replace the windows or opening sashes.
In double glazing of original leaded window we will use the same techniques as we typically do when retrofitting double glazing into sash windows but before placing the new double-glazed units back into the rebated frames, we will add the lead strips to the exterior side of the unit, or to both sides, depending on your preferences and any conservation or listed building requirements.
Example of double glazing unit with lead strips
Using the latest generation of insulated glazing units, like vacuum-insulated FINEO glass or toughened vacuum double glazing made by Landvac, we can transform your original leaded or decorative windows to A-rated energy efficient windows and help you save of energy bills while preserving the historic appearance.
Ultra thin double glazing but more efficient than triple glazing
Vacuum glazing units are the thinnest double glazing available on the market, and due to their vacuum insulation, they are also the most efficient.
This allows us to achieve excellent results for our customers by significantly improving the energy efficiency of their windows while also preserving the character and original wooden frame.
Another benefit of using this particular glazing is the high-quality edge seal, which makes it more durable.
Decorative Leaded Glazing Styles: Square Border, Diamond, Square, Queen Anne
We are able to replicate many of the most common and traditional styles of leaded windows when reglazing original leaded windows.
These include popular designs like Square Border, Diamond, Square, and Queen Anne.
- Square Border:
Simple square pattern, bordered by lead strips. - Diamond: Lead strips arranged in a grid of diamond shapes, often found in Tudor-style and Elizabethan properties.
- Square: Often seen in both Georgian and more contemporary period homes.
- Queen Anne: This intricate pattern, typically characterised by the use of decorative motifs and intersecting lead lines.
Benefits of retrofitting leaded windows with double glazing?
- Efficiency – By adding an additional layer of glass to your windows, you can reduce the amount of heat loss in your home by up to 18%, saving you money and energy.
- Reduce external noise – If road noise is an issue for you, double glazing can reduce noise by up to 31 decibels.
- Reduce UV – Single pane windows can let in a lot of UV light which can damage your art, paint, soft furnishings, and more. Double glazing can stop up to 97% of UV rays from entering your home.
- Solar control – If your home is unbearable in summer, having double glazing can massively reduce how much heat can enter your home during the hottest parts of the year. Double glazing lock heat in your home but keeps the heat outside from entering.
Visual proof of enhanced thermal efficiency of leaded windows
This thermal image shows the enhanced thermal efficiency of a leaded windows and french door after being retrofitted with double glazing.
In thermal photography, colour is used to indicate temperature differences, with warmer areas shown in brighter colour (such as red, orange, or yellow) and cooler areas in darker colour (like purple or blue).
Warmer areas signify greater heat loss, while cooler areas represent better insulation, where heat is retained.
In this image, the door frame and surrounding structure are brighter, indicating some level of heat loss.
However, the glass panes themselves appear much darker, demonstrating that the double-glazed units are doing a far better job of retaining heat and preventing heat loss compared to the frame.
Before retrofitting, single-glazed windows would have shown a much brighter image overall, particularly in the glass areas, due to greater heat escape.
This stark contrast highlights the effectiveness of the new glazing in improving the energy efficiency of the windows, helping to reduce heat loss and keep the space warmer.
Frequently asked questions
Can original leaded lights windows be double glazed?
Yes, but we will need to use one vacuum-insulated unit per opening sash instead of multiple panes of glass or multiple stained glass pieces. We will also add the lead strips on either one or both sides of the insulated glass to replicate the original style of the leaded light window.
Will our original window frame be preserved during retrofitting?
Yes, we will carefully restore your existing wooden windows. We fit new insulated glass units into the existing frames without replacing them.
Our house is listed. Can we still reglaze our leaded windows?
Yes, but you will need to consult your local conservation officer first and obtain building consent.
How much does it cost to double glaze single-glazed leaded windows?
We have some guide prices available on our website, https://scottjameswindows.co.uk/sash-windows-repair-prices/. However, unlike traditional sash windows, leaded windows come in a wide range of styles and sizes.
The best way to get an accurate price is to email us photos, and we will get back to you with an estimate.
Is retrofitting original windows better than secondary glazing?
Yes, because the new glass seamlessly blends with the original frames, giving you all the benefits of modern, highly efficient windows without restricting how you open the window, unlike secondary glazing.
Do you offer safety glass / toughened glass options?
Yes, we can reglaze your sash or casement windows with toughened safety glass.