Single Vs Double Glazed Windows

When you compare single vs double glazed windows, you are really deciding how much comfort, energy efficiency and noise control you want from your windows and doors. On one side you have traditional windows with a single pane of glass. On the other, you have modern double glazing that uses two panes and an air space or argon filled gap to create a thermal barrier.

At Trade Heroes, we connect Australian homeowners, builders and renovators with glazing specialists who work with single glazing, double glazing and even double or triple glazing every day. This guide explains the key differences in simple terms so you can choose the right window types for your home, climate and budget.

What Is Window Glazing?

Window glazing is simply the glass that sits in a window frame or door frame. The glazing can be a single pane, two panes, or even three panes of glass. The way that glass is built and installed has a big impact on heat transfer, energy loss, noise and comfort.

In modern homes, glazing choices range from single glazing through to insulated glass units that use low E glass, laminated glass, argon gas and thermally broken frames to improve thermal performance and energy efficiency.

What Single Glazing Means

Single glazing means each window or door has just one pane of glass between your home and the outside world. This single pane sits in the window frame and the glass acts as the only barrier to heat, cold and sound.

Single glazed windows:

• Use one piece of glass only
• Are common in older homes and traditional windows
• Provide very little thermal barrier against heat gain in summer and heat loss in winter
• Offer limited noise reduction because sound energy can easily vibrate the glass

Single glazed windows are cheaper upfront and simple to repair, which is why they were standard in many existing windows. However, they have poor insulation and can lead to significant heat loss and higher energy consumption in modern homes.

What Double Glazing Means

Double glazing means each window or door uses two panes of glass separated by a sealed air space or argon filled gap. These two panes are built as insulated glass units, often with glass separated by a spacer bar and surrounded by edge seals.

A double glazed window:

• Has two panes of glass instead of one
• Includes an air space or insulating argon gas between panes
• Uses an extra layer of glass and air space to form a thermal barrier that reduces heat flow
• Offers better insulation, energy savings and noise reduction compared to a single glazed window

Double glazed windows offer improved energy efficiency and are often rated under the Window Energy Rating Scheme, which gives star ratings based on thermal performance and solar heat gain characteristics.

Key Differences Between Single And Double Glazing

Single glazing and double glazing look similar from the street, but the way they are built and how they perform are very different.

How They Are Built

Single glazed windows use one pane of glass in the frame, while double glazed windows use two panes of glass separated by an air space or argon filled gap.

Single glazing:

• One pane of glass set into timber, uPVC or aluminium frames
• Glass is usually held in with putty or beads
• No built in air space for insulation

Double glazing:

• Two panes of glass separated by a spacer bar
• Gap typically filled with air or an inert gas such as argon gas
• Edge seals keep the insulating gas in and moisture out
• Built as insulated glass units that are then installed in window and door frames

This extra layer and air space is one of the key differences that allows double glazing to reduce heat transfer and provide better insulation.

How They Perform In Different Climates

In cold climates, single glazing allows significant heat loss, while double glazing provides much better insulation. In hot climates, single glazing can allow high solar heat gain and let cool air escape, while double glazing reduces heat gained through glass.

In colder regions:

• Single glazed windows allow warm indoor air to lose heat quickly through the glass
• Double glazed windows act as a thermal barrier, holding more heat inside and reducing the temperature difference near the glass

In warmer regions:

• Single glazing allows direct sunlight and solar heat gain to build up inside
• Double glazing with low E coating or toned glass can reduce solar heat gain and keep cool air from air conditioners inside longer

Because of these differences, double glazing compared to single glazing performs better across a wide range of Australian climatic conditions.

How They Affect Comfort, Light And Views

Both single and double glazed windows can provide natural light and views, but they feel very different to live with.

Single glazed windows:

• Let in plenty of natural light and fresh air when opened
• Can create cold drafts and hot spots near glass due to poor insulation
• Offer little protection from noise pollution in busy streets

Double glazed windows:

• Provide similar natural light and views with better thermal performance
• Keep the internal pane closer to room temperature so you can sit near the glass without feeling extreme cold or heat
• Reduce noise pollution by damping sound energy as it passes through two panes and an air space

Good window furnishings can help both types, but double glazing gives a stronger base level of comfort and performance.

Energy Efficiency And Performance

Energy efficiency is often the main reason people look at single vs double glazed windows. The difference in thermal performance and energy savings is substantial.

Heat Loss And Heat Gain

Single glazed windows have poor insulation and allow significant heat loss in winter and heat gain in summer. A single pane provides little resistance to heat flow.

Double glazed windows:

• Use two panes and an air space to create a better insulation layer
• Reduce heat transfer through the glass and help maintain comfortable indoor temperatures
• Can reduce heat loss or heat gain through windows by almost 30 percent compared to standard single glazed aluminium windows when specified correctly

By improving the thermal barrier at windows and doors, double glazing can significantly improve your home’s energy efficiency and reduce heat flow in both directions.

Managing Summer Heat And Winter Cold

In summer, single glazing lets solar heat and warm air in easily, driving up cooling costs. In winter, it allows warm air to escape, increasing heating needs.

Double glazing:

• Reduces solar heat gain and keeps more cool air inside during hot weather
• Helps retain warm air inside during colder months
• Works particularly well with thermally broken frames, low E glass and the right window types for your orientation

Because the internal pane stays closer to room temperature, double glazing makes rooms more comfortable year round without relying as heavily on heating and cooling systems.

Condensation And Moisture Control

Condensation is another important part of energy performance and comfort. Single panes often get very cold, so moisture in the air condenses on the glass.

With single glazing:

• The temperature difference between indoor air and the glass is high
• Condensation forms easily on the internal pane
• Over time this can contribute to mould, swelling frames and damaged paints or stains

With double glazing:

• The inner pane is warmer due to the air space or argon filled gap
• Condensation is reduced, so moisture problems are less frequent
• Frames, window furnishings and surrounding finishes are better protected

Reduced condensation is a practical day to day benefit of double glazed windows that many homeowners notice quickly.

Advantages And Disadvantages Of Double Glazing

Double glazing brings a long list of advantages but also has some drawbacks that you should understand before you invest.

Benefits Of Double Glazed Windows

Double glazed windows offer better insulation, noise reduction and overall energy efficiency than single glazed windows.

Main benefits include:

• Better insulation and reduced heat transfer due to two panes and an air space
• Improved energy efficiency and lower energy consumption for heating and cooling
• Lower energy bills and cost savings over time
• Noticeable noise reduction, especially near busy roads or flight paths
• Reduced condensation on the internal pane
• Better security because two panes are harder to break than single panes
• Improved comfort due to smaller temperature difference between inside air and window surfaces
• Contribution to higher energy efficiency ratings for the home, especially when paired with the right frame and glass choices

Double glazed windows can reduce heating and cooling costs by up to about 25 percent compared to single glazing in many homes and can help reduce carbon footprint as a result.

Limitations And Common Concerns

The main limitations of double glazing relate to upfront price, weight and complexity.

Common concerns are:

• The upfront price of double glazed windows is considerably higher than single glazed options
• Double glazing products use more materials and labour, which increases the initial investment
• Insulated glass units are heavier, so installation and supporting frames must be designed carefully
• If a sealed unit fails, repair can mean replacing the whole double glazed window unit rather than just a single pane

Despite these drawbacks, double glazing is widely considered a worthwhile investment because of its long term benefits in comfort, energy savings and home value.

Advantages And Disadvantages Of Single Glazing

Single glazing still has a place, particularly in outbuildings, short term projects and some heritage scenarios, but it also comes with significant limitations.

Benefits Of Single Glazed Windows

The main advantages of single glazed windows are lower upfront cost and simplicity.

Single glazed windows:

• Have a lower initial cost compared to double glazed windows
• Are often more affordable to buy and install
• Are lighter and easier to handle during installation
• Are easier and cheaper to repair if the glass breaks, because there is only one pane

These benefits can be attractive if you have a tight budget or you are dealing with spaces where energy efficiency is less critical.

Limitations And Risks

The downsides of single glazing are mostly about poor insulation and comfort.

Single glazed windows:

• Provide little to no sound insulation and are susceptible to draughts
• Allow significant heat loss in winter and heat gain in summer
• Lead to higher energy costs because heaters and air conditioners must work harder
• Are easier to shatter, which makes them less secure
• Are more prone to condensation due to the cold glass surface

In a modern home where energy efficiency and comfort are priorities, these limitations mean single glazing often costs more in the long run through higher energy bills and less comfort.

Noise, Security And Durability

Beyond energy efficiency, single vs double glazed windows differ in how they handle noise, security and long term durability.

Noise Reduction: Single Vs Double Glazed

Double glazed windows offer better sound insulation than single glazed windows because sound energy must pass through two panes and an air space.

Single glazing:

• Uses a single pane that vibrates easily when hit by sound waves
• Lets more outside noise into living spaces

Double glazing:

• Uses two panes and an air space that help break up and reduce sound energy
• Can significantly reduce noise pollution in homes near busy roads, rail lines or schools

In practice, homeowners who upgrade from single to double glazing often report that traffic and street noise drops to a much more manageable level.

Security And Impact Resistance

Security is another area where double glazing usually wins.

Single glazed windows:

• Use one pane that is easier to break with impact
• Provide less resistance to forced entry

Double glazed windows:

• Use two panes of glass, which are harder and slower to break through
• Can incorporate laminated glass or toughened glass for greater impact resistance
• Provide an extra layer that improves overall window security

For ground floor windows and doors, choosing double glazed units with the right glass specification can make a meaningful difference to home security.

Lifespan And Maintenance

Both single and double glazed windows can last for many years, but their performance over time is different.

Single glazing:

• Has simple glass but may be in older frames with poor insulation and ageing seals
• Can be affected more by condensation, which encourages rot and corrosion in some frame types

Double glazing:

• Uses sealed insulated glass units that are designed for long service life
• Reduces internal condensation, which helps protect frames and window furnishings
• Often sits in modern frames such as thermally broken aluminium frames or uPVC systems that resist warping and weathering

With proper installation and sensible maintenance, double glazed windows can provide durable performance and better insulation over the long term.

Cost, Savings And Resale Value

The decision between single vs double glazed windows is not just about initial price. It also affects running costs and future resale value.

Upfront Cost Comparison

Single glazed windows have a lower initial cost than double glazed windows, which is why they are still used in some projects.

However:

• Double glazed windows are typically more expensive because they use two panes, spacer bars, seals and more complex construction
• The additional materials and labour increase the price per unit
• Triple glazing usually costs more again but can further reduce heating and cooling costs in cold climates

For most homes, double glazing represents a higher initial investment, but it is important to weigh that against long term energy savings and improved comfort.

Energy Bill Savings Over Time

Double glazing can reduce ongoing heating and cooling costs compared to single glazing.

In real homes:

• Double glazed windows can help lower energy bills by improving a home’s energy efficiency
• They can reduce heating and cooling costs by up to about 25 percent compared to single glazed windows when correctly specified
• Energy savings vary depending on climate, orientation and other insulation, but the pattern is consistent

Over time, these lower bills help offset the initial investment in double glazing and reduce reliance on artificial heating and cooling.

Impact On Property Value And Buyer Appeal

Glazing choices can also affect property value and buyer appeal.

Double glazed windows:

• Are widely considered a smart investment for long term comfort, efficiency and home value
• Can help increase the resale value of a home because buyers recognise the benefits of energy efficient windows
• Are among the top requested features in many new homes, alongside other energy efficient inclusions

By improving your home’s energy efficiency, thermal comfort and noise levels, double glazing makes the property more attractive in a competitive market.

Options For Upgrading Existing Windows

If you currently have single glazed windows, you have more options than just full replacement with new windows. Secondary glazing, films and coatings can improve performance.

Secondary Glazing For Single Glazed Windows

Secondary glazing is an extra pane of glass or clear acrylic added to existing single glazed windows to create an air space and improve insulation.

Typically:

• A second layer is installed using frames or magnetic strips on or near the existing window
• The new layer and original glass create an enclosed air space that reduces heat transfer and air infiltration
• Thermal performance improves and noise reduction can also improve noticeably

Secondary glazing is a practical option for heritage homes and situations where you want to keep existing windows and frames but still improve energy efficiency and comfort.

Glazing Films And Other Improvements

Glazing films and alternative glass options can also help existing single glazed windows perform better.

Common choices include:

• Glazing films that can be fitted to glass to reduce leaking solar energy and glare
• Toned glass that reduces the amount of heat transmitted and can also reduce light and heat gain in winter and summer
• Reflective coatings that can be applied to new and existing windows to stop more heat gain than some toned glass
• Low E coating on the internal pane of a double glazed window to reduce winter heat loss
• Glass louvres that use multiple glass panels to control ventilation and natural light, though they offer less insulation than double glazing

These options cannot fully match the performance of double or triple glazing, but they can improve the thermal performance of existing windows and help reduce energy consumption.

Should I Install Single Or Double Glazed Windows?

The choice between single vs double glazed windows depends on your climate, budget, existing windows and priorities for comfort and cost savings.

Factors To Consider For Your Home And Climate

Choosing the right glazing for your home has a significant impact on energy efficiency, performance and resale value.

Key factors are:

• Climate and temperature range in your area
• Orientation and size of your glazed windows and doors
• Existing issues with heat, cold, condensation or noise pollution
• Type of window frame and whether you are replacing frames as well as glass
• Your budget and how long you plan to stay in the home

The type and design of glazing, along with frame choice, is critical to thermal performance, comfort and the long term economy of your home.

When Double Glazing Is Worth The Investment

Double glazing is usually worth the investment when you want better insulation, energy efficiency and noise reduction.

It is especially recommended when:

• You live in a climate with cold winters, hot summers or both
• You currently have significant heat loss or heat gain through single glazing
• You want to reduce energy bills and improve your home’s energy efficiency rating
• You are planning a major renovation or building new windows and doors

In these situations, double glazed windows offer better insulation and energy savings that justify the higher initial investment.

When Single Glazing Or Upgrades May Be Enough

Single glazing or upgrade strategies may still be acceptable in some specific cases.

For example:

• Sheds, garages, short term rentals or low use rooms where comfort is less critical
• Heritage homes where you want to retain original frames and use secondary glazing to improve performance
• Very mild climates where temperature swings and energy costs are lower

In these scenarios, combinations of secondary glazing, glazing films, toned glass, good window furnishings and draught sealing can improve comfort without fully replacing every window immediately.

Conclusion

If you would like help deciding what makes sense for your home, Trade Heroes can connect you with trusted glazing and window specialists across Australia who understand single vs double glazed windows, secondary glazing and advanced options like triple glazing and low E glass. Visit Trade Heroes today, compare quotes and solutions for your windows and doors, and take the next step toward a more comfortable, quieter and energy efficient home.