Double-Glazed Windows: In-Depth Buyers’ Guide

8 min read Windows

Double-Glazed Windows: In-Depth Buyers’ Guide & FAQs

Homeowners are often stuck on double and triple glazing when exploring window installation and replacement options. Despite the heavy price tag, double-glazed windows (double-paned or dual-pane windows) have emerged as a popular choice for residential properties over the past decade. All thanks to its high-end energy efficiency, heat loss prevention, and noise reduction features.

While it is an integral part of modern homes in the UK, there are endless possibilities to upgrade to double-glazing in traditional buildings.

But before investing, it is worth knowing how it works, the potential benefits, costs, top brands/models, etc.

In this article, I will share all the details of dual pane models, how they work, different types and styles, advantages and disadvantages, costs and why you need a professional installation company. Do read the FAQs answered by industry experts.

uPVC window


What are Double-Glazed Windows?

A double-glazed window (framed or unframed) has two bonded glass panes with an intervening gap (air pockets) containing air or inert gas. Gas-filled glasses are pricey, offering better insulation and warmth than their air-filled counterparts.

The air pockets are filled with any of these three types of inert gases:

Argon- Argon is affordable and widely used for double glazing. It is a safe, non-toxic, and non-reactive gas for making windows more energy efficient. This inert gas does not conduct heat, offers enhanced insulation, and prevents frost buildup at the base in winter.
Krypton- This gas is denser, costlier, and more energy efficient than Argon. It is a reliable option for filling small gaps in triple-glazed windows.

Dual glazing technology needs no introduction to the construction industry. The mechanism of joining two glasses within a single frame was first proposed by C.D. Haven in 1930 in the USA. However, the earliest installation of dual pane windows in UK homes dates back to the 1970s when property owners were forced to source energy efficiency alternatives in the event of shooting fuel costs.

How Double-Glazing Windows Works?

A double-pane window is made of the following components:

two glass sheets (4mm-6mm thickness)
insulating gas

A small gap between the two glass panels is filled with inert gas. The desiccants prevent condensation/fogging and trap moisture in the air pockets. These windows allow the sunlight to pass through, brightening the rooms during the daytime.

The insulation layer, filled with Argon gas, traps and retains heat, minimising the power consumption by heating appliances/ACs in domestic units. The thermal transfer rate of Argon is 34% lower than air. When heat from the external glass is transmitted to the gas layer, it traps heat without passing it to the internal glass panel. It makes your homes highly energy efficient and cuts expenses on monthly bills in winter.

Types of Double-Glazed Glasses

There is a range of double glass panels for window installation in residential properties.
Low-E (Low-Emissivity) GlassThese glasses are treated with a thin low-E coating on one side for enhanced insulation and high-end energy efficiency.

Annealed/Float Glass

Float glasses are low-cost standard glasses for double-glazing windows. These glasses are soft and vulnerable to breaking.

2. Toughened/Tempered Glass

These glasses are safe, sturdy, and durable. The annealed glass panels are exposed to thermal and chemical treatment, making them four times more force-resistant than ordinary glasses.

3. Laminated Glass

Laminated glasses, best known for noise reduction, are made by bonding two glass sheets with polyvinyl butyral (PVB) resin. PVB resin creates a secure layer to restrict broken glass pieces from scattering.

4. Noise Reduction Glass

Generally made of thick glass panels, the pieces are coated with a PVB layer to cut noise by 34 decibels (90%).

5. Self-Cleaning Glass

As the name suggests, these glasses have a dirt-resistant outer coating. This is a preferable solution to save time and money on cleaning costs. There are two types of self-cleaning glasses:

Hydrophobic – The chemical layer on these glasses repel moisture and dust particles.
Hydrophilic – The titanium dioxide coating on the surface of these glasses triggers photocatalysis, eliminating dirt when exposed to sunlight.


Double Glazing Window Types and Styles

Today buyers can replace old windows with state-of-the-art double-glazed glasses (available in different types and styles) designed for varying construction purposes. This ensures you find a match for your home architecture pattern.

#1. Tilt and Turn

These windows with dual hinges at the bottom are ideal for safety in children’s rooms.

#2. Casement

Casement double-pane windows are suited for an influx of natural daylight in big homes.

#3. Vertical Sliding

The vertical sliding window looks like a sash window that opens and closes into the same unit without occupying internal or external space when opened.

#4. Bay (Multiple Panels)

Bay windows are designed with three or more panes that open outwards. These panels can be customised to form a linear or arc pattern to maximise internal space and alleviate aesthetics.

#5. Gregorian Bar

The iconic Gregorian bar is ideal for homes with classic architecture. Upgrading to a dual-glazing version requires milling and joining multiple double panes to a single frame to create an identical multi-pane look.

#6. Flush Fit

Flush-fit windows have an advanced energy-efficiency mechanism where the sash fits into the frame without any obstructing part.

#7. Fully Reversible

These windows are made of a wide glass panel enclosed in solid frames for a clutter-free look. This style is ideal for modern homes, allowing plenty of light and air in summer. The dual panes ensure insulation and heat retention during the frost season.

Are Double-Pane Windows Worth the Investment

Double-glazed windows are beyond aesthetics. Whether you want to install new windows or renovate old ones, herein is an overview of the potential benefits and downsides of installing dual-pane glasses.


These windows provide thermal insulation by trapping heat, so you can save on energy costs.
Dual-panel glasses are sturdy and durable. They are hard to break, creating a security layer to obstruct intruders from entering the indoor premises.
The insulation gap dampens soundwaves and cuts outdoor noise by 90%
Double-pane windows are available in various luxurious designs to match your home decor. Upgrading to double panels accents the curb appeal and boosts return on investment (ROI) for any property value.


Can be expensive
A broken seal cannot be replaced/repaired.
Double-panel windows allow sunrays through the glass and gas layers. However, the insulation system traps heat to keep the rooms warm. This works well in cold months but is not ideal for summer. Go for tinted glasses to repel heat.

Are Double-Glazing Windows Environment-Friendly?

There are multiple positive impacts of installing double-pane windows on the planet and staying low on carbon footprint.

A house fully covered with dual-panel glasses gets heat from natural sunlight. It means you are using less energy on heating appliances to beat the chills in winter. With adept insulation, this can lower carbon dioxide emissions by 680 kgs a year per home.

Dual Pane Windows Pricing

The cost of double-glazing your home depends on several factors:

Window type, size, and style
Type of double-glazed-glass
Frame material
Brand and model

Window installation

Choosing a double-glazing window installation company depends on reputation, available options, energy ratings, and more. Sheerwater Glass offers value with every project, and guaranteed high-quality products.

It’s possible to fit double glazing yourself, but not advisable. Not that is, unless you know exactly what you’re doing. The windows are too expensive to make a mistake with. You’ll also need approval from the Building Regulations team at your local council, as well as the help of a site assessor to ensure your home will have enough ventilation and energy proficiency.

Also, make sure the type of frame you want is suitable for your home (if your house is ‘listed’ you’ll be restricted in choice of materials, for instance.)


#1. Double vs. triple-glazed windows- What is the difference?

A double-glazed window comprises two glass panes with a small gas pocket in between. The triple-glazed (triple-paned) window has three glass panes and two air pockets filled with insulating gas. Here is a quick comparison:

Triple-pane models are more expensive than double-glazed windows.
Triple glazing assures greater energy efficiency than dual-glazed glasses.
Dual pane glass can cut the sound levels by 32 decibels. Laminated double-pane glasses offer up to 37 DB sound reduction. Triple pane laminated glasses can reduce outside noise by 40DB.

#2. Can double-glazed windows block outdoor noise?

Yes. Double glazing dampens sound waves, reducing outside noise by 31-37 decibels. However, it is not a complete soundproofing solution for your rooms. If you are having issues with traffic or airport noises, windows with acoustic interlayers can significantly lower the noise disturbances.

#3. How long do double-glazed windows last?

The lifespan of a double-pane window is 20-30 years, depending on the exposure to extreme conditions. The exterior glasses bearing maximum weather impact last for up to 20 years. Windows installed in a sheltered location can last for 25-30 years.

Upgrading to Double Glazed Windows Assures Maximum ROI

Double-glazing is an indispensable choice for replacing old single-panel windows in traditional homes. It is a one-time investment to save money on winter energy bills annually. A+ rated dual pane windows in detached homes can lower energy costs by £200-£285 per year.

These long-lasting modish windows are crafted in various styles, designs, and patterns, giving you ample interior makeover options. Dual-pane insulated windows are available at varying prices that fit different home renovation budget slabs. Casement windows with uPVC frames are affordable options starting at £300 per window.

Choosing a window design and material can be a daunting experience. It is always worth consulting your choices with a local window company to receive a quote.


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