If your timber sash windows feel cold, draughty or noisy, you’re not alone. Traditional sash windows are often single glazed and can allow heat loss, condensation and outside noise into your home.
Notorious for having poor thermal performance, draughty, inefficient sash windows result in not just decreased levels of comfort but also, increasingly higher energy costs.
As well as being expensive to change, replacement options are often limited by local conservation and planning rules.
WindowSkins magnetic secondary glazing is an attractive, affordable solution for timber sash windows – improving insulation and comfort whilst preserving the original character of your period property.
Approved for Listed Buildings & Conservation Areas, WindowSkins significantly reduces problems related to Cold, Draught, Condensation and Noise.
Not just effective, the near-invisible design offers an unrivalled elegance and discreet aesthetic.
We offer a comprehensive measure, supply & professional fit service.
Common Problems with Sash Windows
Traditional sash windows are beautiful, but they often come with common issues ;
- Cold draughts from (often large) gaps in frames and sashes
- Heat loss though (often thin) single glazed glass
- Condensation build-up on glass (with associated rot and mould growth if left unchecked)
- Outside noise and pollutants entering the home
- High (and rising) energy bills due to poor insulation
- Limited (and often expensive) replacement options due to conservation and planning rules
These problems are especially noticeable in older period properties and listed buildings.
The Benefits of Magnetic Secondary Glazing for Sash Windows
WindowSkins magnetic secondary glazing is a modern, practical solution for homeowners who want better insulation and comfort while retaining their original timber framed sash windows.
Reduce Cold and Heat Loss
By creating an insulating air gap behind the existing glass, WindowSkins secondary glazing helps reduce heat loss through single glazed sash windows. Rooms feel warmer and more comfortable, particularly in winter.
Minimise Draught
Sash windows can be prone to cold draughts through air gaps and convection currents. WindowSkins secondary glazing helps prevent this and improves comfort throughout the room, especially in nearby seated areas.
Control Condensation
Condensation often forms on cold sash windows and single glazed panes. Secondary glazing helps improve the thermal performance of the window, reducing cold surfaces thereby helping to limit condensation build-up.
Improve Noise Reduction
If your property is near a road, school, railway line or other external noise source, WindowSkins secondary glazing can help reduce the amount of sound coming through older windows.
Preserve Original Character
Timber sash windows are an important part of a period property’s character. WindowSkins magnetic secondary glazing is discreet and removable, helping preserve the look of the original windows. Approved for Conservation Areas and Listed Buildings.
Summer Heat & Pollution
Reduces penetration of pollutants and particulates into the home and, can help homes feel cooler during the summer, especially if air conditioned.
Lower Costs
Compared to traditional secondary and double glazed solutions, WindowSkins is an affordable alternative. Start saving with lower monthly energy bills.
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Build Specification
Our magnetic Sash WindowSkins are typically built using 3mm Acrylic XT panels, paired with premium 20mm magnetic tapes.
Every WindowSkin is carefully crafted with exacting mitre joins in each corner, adhered with a premium foam backed TESA adhesive for long lasting use.
Precision laser measuring using our proprietary software solution ensures a perfect fit every time, even for irregular shaped windows.
The magnetic system creates an airtight seal, and is complemented with our patented secondary fixings for venting and stability.
This significantly reduces the problems of Cold, Draught, Condensation and Noise.
Where noise is of primary concern, we can increase the panel thickness to 4mm.
For Sash Windows, There Are Two Possible Mounting Points
Outer Placement
(Standard Placement)
This is where magnetic tapes are fit to the sash frame surround (inner-lining), close to the outside edge of the beading.
This is the default (and simplest) fitting but, requires adequate space around the frame of the sash window.
The minimum reveal space required for optimal fitting is 25mm and should ideally be clear of obstructions.
Paintwork should be in fair condition and the window in a reasonable state of repair.
Click here to view ‘Outer Placement’ image examples
Subframe Placement
This is where a magnetised 20mm subframe is fit to the inside edge of the sash window beading.
This is the more discreet option, as the WindowSkin sits within the beading recess and, can often be a preferred option to the Outer Placement.
Subframes are typically used in tight situations, where there are shutters, narrow frames surrounds or other obstructions preventing fitting in the Outer Placement.
Constructed using PVC, the subframe design is unobtrusive and does not reduce visibility through the sash window.
Available in White or Teak, but can be painted or vinyl coated to a colour of your choice.
Click here to view ‘Subframe Placement’ image examples
Regardless of chosen placement, either type are equally effective at reducing Cold, Draught, Condensation and Noise
Obstructions
Regardless of obstruction, our specialist expertise provides for a myriad of often simple solutions to seemingly difficult problems.
Typical obstructions are outlined below;
- Narrow/Uneven Surfaces: where part or all of the sash box frame (inner-lining, sill/apron) is narrow or uneven.
- Flaky Paintwork: which will likely cause the magnetic tapes adhesive to fail over time.
- Blinds: generally compatible we get around these by remounting the blind on spacers or fitting a subframe.
- Shutters: usually require a Subframe Placement to maintain compatibility.
- Sash Lifts: protruding lifts can usually be pressed or replaced with a suitable alternative.
- Locks : are generally compatible with alternative solutions readily available.
- Low Voltage Cables: we usually embed or reposition low voltage cables and junction boxes.
- Alarm Sensors: if obstructing, they may need repositioning by a qualified technician.
Please note that all workarounds are on a best efforts basis so compatibility is not always guaranteed.
Secondary Fixings
As well as being magnetically attached, our patented Secondary Fixings ensure your WindowSkins remains fast, even in the windiest weather.
Located in the upper corners of each panel, the secondary fixings serve to prevent accidental slippage especially where curious little fingers are at play.
They also facilitate venting using our supplied Venting Arm and, simplify alignment when removing and refitting.
Apart from a small step, no special tooling is required during the removal & refit process.
Split Panels
For larger sash windows, we also offer a ‘split panel’ option.
This is where the WindowSkin is constructed as two parts, upper and lower, butting together in front of the sash meeting rail. They are joined using the supplied magnetic connector, and when in place form one continuous panel.
Split Panels are convenient, as access to the meeting rail is made easier when venting (to access locks and lift the bottom sash).
They are also practical for storage, collapsing down to a smaller form factor, which can simplify storage during summer.
Closeup of a Split Panel WindowSkin fitted to a Sash Window
(Click image to enlarge)
Split Panel Recommendation
We usually only recommend Split Panels when;
- The window is functional, openable and used.
- You intend to remove, store and ventilate in summer.
- The sash windows are taller than 1.6 metres in height (i.e. they will not fit under a double bed).
- Storage space is limited in the home.
Split Panels usually require a second pair of our patented Secondary Fixings, which facilitates Venting Arm use.
It is aesthetically appropriate to mix split and single panels, for example having the (often larger) centre window split in a three window sash bay.
A good option for smaller sash windows, is to go for a functionally cleaner ‘lift-out’ option where only the upper panel has patented Secondary Fixings. In this configuration, the bottom panel is removed and rested nearby. (The Venting Arm cannot be used in this configuration)
Venting
It is possible to ventilate during the winter, using our proprietary 3D printed Venting Arm.
This works in combination with the patented Secondary Fixings, allowing you to pull the WindowSkin away and open the bottom sash six to eight inches.
The Venting Arm then serves to prop the WindowSkin open, allowing air to pass through, without having to remove the panel.
During the warmer summer months, WindowSkins can be easily removed, without tools, and stored for continuous and frequent opening of the window.
Storage
WindowSkins are designed to be easily removed, and can be stored during the summer months.
Whilst not a requirement (they may be left in place year round), this can be convenient for frequently opened windows.
Typically weighing around 6-8kg for a large sash WindowSkin, they are light enough to be handled easily. Split Panels are a good complementary option also.
They can be wrapped in bubble wrap or a soft cotton sheet, and stored flat under a double bed.
Alternatively, we can provide felt lined storage sleeves at additional cost.
Colour Matching
WindowSkins are available in white or a natural ‘Brown-Black’ as standard.
Unlike most, our white magnetic tapes are not just white on the front face but also both leading edges.
This ensures there are no unsightly black lines on either panel or window.
It is also possible to colour match using most water based paints or from an extensive range of wood grain vinyl finishes (at additional cost).
We find that Farrow & Ball paints (Estate Eggshell, 20% sheen) work particularly well and appear to be most popular. We have also had good results with Little Greene, COAT & Earthborn paints.
Our paintworks comprise three coats (one primer, two top coats) and each panel is individually masked to prevent overspray. The final result is a smooth spray finish with crisp lines and minimal bleed.
Additionally, all magnetic tapes, subframes (where present) and most ancillary components are included for colour matching.
Click here to view ‘Colour Matching’ image examples
Shutters
WindowSkins offers excellent compatibility with most types of shutters, including modern plantation and traditional Georgian & Victorian panel shutters.
In most circumstances we are able to fit inside the sash beading recess using the Subframe Placement.
For Plantation Shutters, it is important to note;
- The shutter frame does not excessively overlap the inside edge of the sash beading.
- Venting Arm usage is dependent on available frame and shutter door clearance.
In cases where the shutter frame significantly overlaps the sash beading, we instead opt for an inverted subframe, fit directly to the back line of the shutter frame itself.
A minor drawback of the inverted fit method is that shutter louvres may, on occasion, only open 90% of the way due to a shared space requirement. However, in such cases, the performance trade-off is usually worthwhile (shutter doors can also be left slightly ajar if needed).
For Panel Shutters, sufficient depth of sash beading is required (typically 22mm) to ensure shutter doors can fully close and, shutter knobs, where fitted, may need removal.
In some circumstances, we may also need to remount the shutter hinge on spacers to provide some extra depth.
(It is important to note that 100% compatibility is not guaranteed and fitting for such is always on a best efforts basis)
Click here to view more Shutter image examples
Materials
WindowSkins are constructed using one of the following panel types;
- 1.5mm PETG (curved windows)
- 2mm PETG (standard build)
- 3mm Acrylic XT (recommended)
- 4mm Acrylic XT (best for noise)
PETG panels offer excellent impact resistance, allowing for a lightweight panel that is flexible, yet easy to handle, all whilst retaining strength.
For 3mm & 4mm panels, we switch to Acrylic XT.
Acrylic XT is a harder material, giving it increased durability in terms of scuffing and scratch resistance.
It also offers excellent optical clarity and our magnetic tapes show up brighter and whiter (when compared to PETG).
The additional stiffness from thicker materials may be better suited for larger sash windows (especially if draughty).
Finally, it should be noted that both materials provide excellent UV stability.
Noise & Air Pollution
WindowSkins are a proven and effective solution to noise related problems (pedestrian, traffic, aircraft etc), with a comparative acoustic dampening performance similar to glass.
- 2mm panels reduce noise by around 30%
- 3mm panels reduce noise by around 40%
- 4mm panels reduce noise by around 50%
Where noise is concerned, the depth of air gap between glass and panel is highly important. For this reason, secondary glazing generally outperforms double glazing, due to the larger air gap.
Incidentally, it is found that WindowSkins also serves to reduce the infusion of air pollutants and particulate matter into the home (as well as the occasional creepy crawly!)
When paired with good quality HEPA filtration, indoor air quality may be significantly improved, along with obvious associated health benefits.
Irregular Windows
One of the challenges to fitting modern rectangular glazing panels against period timber windows, is that the windows are rarely true (i.e. they are asymmetrical).
Originally handcrafted, timber window fabrication was highly dependent on the skill and accuracy of the carpenter or joiner. This often leads to irregularities in shape.
Over time, the effects of weathering and subsidence can further exacerbate those irregularities. For example, this could make a window subtly diamond shaped.
Without correction, this can lead to ill-fitting panels, often too short and with poor alignment against the windows, which is aesthetically displeasing.
Our proprietary software and laser surveying solution measures every windows dimension and geometry making the necessary correcting adjustment for asymmetrical window frames, as standard.
We later trim those panels, in our workshop, to replicate those very same irregularities for near-perfect results.
Curved & Arched
WindowSkins are a cost effective solution to the complexities caused by arched and curved windows.
For arched windows (rounded at the top), we employ a proprietary templating method for near perfect results.
Unlike our regular CNC cut panels, arched panels are carefully cut by hand, in our workshop, using a custom jig to ensure accuracy.
Ideally we opt for the Outer Placement but, where space is limited, we also have an arched subframe option.
For curved glass windows we employ a hybrid measure system, with additional computation for window irregularity across the chord.
So that the WindowSkin can follow the curvature of the window frame, panel flexibility is required. For this reason, we limit maximum panel thickness to 2mm with 1.5mm being more likely.
Whilst this does not significantly affect thermal efficacy, noise reduction is limited to around 25-30%.
As before, if space is limited, we switch to a curved subframe option.
Care
With a little care, WindowSkins should give you years of trouble-free service – providing warmth, comfort and noise reduction.
The key rule for WindowSkins is no harsh abrasives.
We recommend gentle cleaning using mild detergent, water and a microfibre cloth.
A quality soft rubber or silicone squeegee may also be used, with light pressure, for larger areas.
For smaller spot cleaning, isopropyl alcohol or non-vinegar glass cleaner may be used with soft tissue.
Every WindowSkin has a room and window specific identifying label making storage and replacement simple.
And of course, all WindowSkins are covered by a three year repair or replace warranty with phone, email and postal support.
Are you ready for a warmer, quieter, more comfortable home?
Arrange Your Free Correspondence Quote Today
