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A Comprehensive Guide to Sash Windows: Features, Pros, Cons, and FAQs

Sash windows are more than just windows; they’re a timeless architectural element that imbues buildings with a distinctive charm. Often found in Georgian and Victorian properties, these features add an undeniable charm to any structure.

But what exactly makes a window a “sash” window? This comprehensive guide will delve into their fascinating world, unveiling their unique mechanisms, exploring their advantages and disadvantages, and addressing the most frequently asked questions surrounding them.

Sash Window we installed for a customer at their home in Burwood NSW

How do Sash Windows Work?

A sash window is composed of two essential parts: a movable panel (sash) holding the glass and a frame that keeps it in place. Traditionally, weights made of steel, cast-iron, or lead, hung on cords within the frame, operated the window. Modern versions utilize a spring balance system, eliminating the need for cords and pulleys, allowing for effortless opening and closing.

How do sash windows work?

Sash Windows: Pros and Cons


Timeless DesignUndeniable beauty and character, complements various styles
Excellent VentilationTop and bottom opening for air circulation
Secure VentilationLockable mechanisms for safety
Long LifespanDurable and long-lasting when maintained
Double Glazing OptionImproves energy efficiency and reduces noise
CustomizabilityVariety of materials, styles, and colors


Higher Initial CostMore expensive due to design and materials
More Complex MaintenanceRequires more upkeep due to moving parts
Painting Requires Special TechniquesNeeds correct techniques to avoid damage
Limited OpeningCan only open partially
DraftyCan lead to higher energy bills if not sealed properly
Difficult to Find Matching ReplacementsCustom specifications may be challenging to match

Sash Window Materials: Exploring Options and Trade-Offs

Sash windows are not just about aesthetics, the material used plays a crucial role in their performance, durability, and cost. Let's delve into the most popular options:

1. Timber:


  • Natural beauty and elegance
  • Superior thermal insulation
  • Durability and longevity
  • Environmentally friendly


  • Higher initial cost
  • Requires regular maintenance
  • Susceptible to warping and rot

2. uPVC:


  • Affordable
  • Low maintenance
  • Weather-resistant
  • Energy efficient


  • Limited aesthetic appeal
  • Not as durable as timber
  • Environmentally unfriendly

3. Aluminium:


  • Sleek and modern aesthetic
  • Durable and strong
  • Low maintenance
  • Energy efficient


  • Higher cost than uPVC
  • Poor thermal performance without thermal breaks
  • Limited colour options

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Feature Timber uPVC Aluminium
Aesthetics Natural beauty, warmth Modern, sleek Contemporary, minimalist
Durability High Moderate High
Maintenance High Low Low
Weather resistance Moderate High High
Energy efficiency High Good Good (with thermal breaks)
Cost High Low Moderate
Environmentally friendly Yes No No
Read the following posts for more information on different types of window materials:

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Comparison of Window Types

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Feature Sash Windows Sliding Windows Casement Windows Awning Windows
Design Classic, elegant Modern, minimalistic Functional, traditional Contemporary, versatile
Ventilation Top and bottom opening Side-to-side opening Outward opening Top hinged, outward opening
Security Lockable, moderate security Lockable, good security Secure locking mechanism Lockable, secure when partially open
Maintenance More complex, regular upkeep Minimal, easy to clean Regular maintenance required Minimal maintenance
Cost Higher initial cost Varies, generally affordable Mid-range cost Varies, generally affordable
Customization Highly customizable Limited customization Customizable Some customization options
Energy Efficiency Good with double glazing Good, depends on materials Very good with appropriate design Good, especially for rain protection
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Are Sash Windows a Worthy Investment?

In a new build, sash windows add a touch of prestige that’s difficult to rival, particularly in a property inspired by past architectural eras. Although they come with a higher price tag than standard UPVC or timber windows, their lifespan with appropriate maintenance can justify the initial investment.

They are nearly indispensable in properties dating back to the 17th to 19th centuries, such as Georgian, Regency, or Victorian properties, or in traditional-style new homes. However, if practicality and cost are primary concerns, alternatives might be more suitable.


What materials are sash windows typically made of?

Sash windows are traditionally crafted from timber, due to its natural insulating properties and classic aesthetics. However, modern sash windows are also available in uPVC or aluminum, offering more durability and requiring less maintenance.

Can sash windows be double glazed?

Yes, sash windows can indeed be double glazed, and in fact, it’s a highly recommended upgrade for both historical and modern properties. Double glazing offers a range of benefits, including:

  1. Improved Energy Efficiency: Double glazing adds an additional layer of insulation between your home and the outside environment. This helps to trap heat in the winter and keep the cool air in during the summer, resulting in significant energy savings on your heating and cooling bills.
  2. Reduced Noise Pollution: The double-paned design of double glazed windows effectively blocks out noise from outside, creating a quieter and more peaceful living environment. This is especially beneficial for homes located in busy or noisy areas.
  3. Increased Comfort: Along with improved temperature control, double glazing helps to reduce drafts and condensation, creating a more comfortable living space throughout the year.
  4. Enhanced Security: Double glazed windows are inherently stronger and more secure than single-glazed windows, making them more difficult to break into. This can provide peace of mind and improve the overall security of your home.
  5. Reduced UV Radiation: Double glazing helps to block harmful UV rays from entering your home, protecting your furniture, carpets, and artwork from fading.

Can you paint sash windows?

Yes, sash windows can be painted. In fact, regular painting is important for timber sash windows to protect them from the elements and keep them looking their best. Care must be taken when painting to ensure that the window’s operation isn’t affected, particularly with the unique sliding mechanism of sash windows.

Can sash windows be repaired?

Yes, sash windows can be repaired. Common repairs include broken window glass replacement, repairing or replacing rotten wood, and fixing broken cords or springs. It is also possible to retrofit insulation into the counterweight pockets of older sash windows to improve energy efficiency.

How can you make old sash windows more energy efficient?

There are several ways to make old sash windows more energy efficient, including installing weatherstripping, adding window film, replacing the glazing to low E glass, installing sash window inserts, adding window insulation, installing storm windows, and using draft excluders. By implementing these measures, you can significantly improve the energy efficiency of your old sash windows.

How can you enhance the security of your sash windows?

Improving the security of sash windows can be achieved through a few strategies. Here are some suggestions:

  1. Locks: Invest in quality locks specifically designed for sash windows. These can be key-operated and often allow for the window to be locked in an ajar position, providing ventilation while maintaining security.

  2. Glass: Consider replacing the glass with laminated or toughened glass, which is harder to break and can therefore deter potential intruders.

  3. Window restrictors: These devices limit how much the window can be opened, preventing someone from gaining access but still allowing for ventilation.

  4. Security grilles or bars: While they may alter the appearance of your windows, security grilles or bars can provide a robust level of security. Opt for designs that complement the look of your property.

  5. Alarm systems: Window sensors that connect to your home alarm system can alert you if the window is opened or broken.

Picture of Phillip Sharp
Phillip Sharp

Phillip Sharp has spent more than three decades honing his skills as a glazier in Sydney. He is currently employed at Splendid Window Glass Repairs, where he specializes in glass replacement and repair in the Sydney Eastern Suburbs area. With his wealth of experience and commitment to excellent craftsmanship, Phillip is highly respected in the industry and trusted by clients to provide top-quality work.