Secondary Glazing: The Affordable Choice vs Double Glazing

What is Secondary Glazing?

Secondary glazing is the installation of a glazed panel in a thin frame behind an existing window. The gap between the window and the secondary glazing creates an insulation barrier that improves noise reduction and energy efficiency by reducing draughts and enhancing heat retention. 

Because it’s relatively cheaper than double glazing, secondary glazing is the preferred alternative for homeowners with budget constraints looking for thermal and acoustic insulation. Another common reason for installing it instead of double glazing is planning restrictions.

If you live in a listed building or conservation area, you need to obtain planning permissions before you can install double glazing. On the other hand, because secondary glazing doesn’t change the original architectural style of windows, planning authorities typically consider it an acceptable upgrade. You can even install it yourself. Actually, there are various kinds of secondary glazing units that you can install, depending on the type of window you have. Below are some of the most common ones:

Kinds of Secondary Glazing
Horizontal Sliding	Ideal for wide multi-pane windows with vertical bars. Provides easy access to the original window for improved ventilation.
Vertical Sliding	Perfect for windows with horizontal bars like box sash windows. Panels move up and down easily and tilt inward for cleaning access.
Hinged	Suitable for traditional casement windows and bays. Swings open like these window types, offering greater ventilation and full access.
Lift-Out	Ideal for windows in tight spaces. Provides occasional access when needed.
Fixed	Ideal when access to existing units is not needed. Ultra-slim and easy to fit.
Magnetic	Acrylic panels with magnetic strips for easy removal. Ideal for quick and easy installation. Suitable for those who prioritize convenience.

Now, you may be wondering: What are the advantages of secondary glazing, and does it actually work just as effectively as double glazing? Find out in the next sections.

The Benefits of Secondary Glazing

But how can secondary glazing match or even surpass the performance of double glazing? Here are the key benefits of installing it in your home:

Enhances Energy Efficiency

The additional layer of fully glazed glass creates an air gap between itself and the existing window, creating a vacuum. This provides extra insulation and reduces the amount of heat transfer, keeping your home warmer in the winter and cooler in the summer without inflating your energy bills.

Excellent Noise Reduction

Secondary glazing is one of the most efficient ways to reduce external noise, making it ideal if you live in a noisy environment. 

The gap between the two panes of glass in double-glazing units is 16 to 20mm, while secondary glazing can create a gap of more than 100mm. The wider the gap, the more the sound is reduced. A secondary glazing of laminated glass with a 100-mm gap can reduce noise by up to 35 dB.

Unobtrusive Design

If you want to retain the original style of your windows, secondary glazing is the perfect solution because units usually come with a slim frame. These frames blend seamlessly with the existing architectural style of your property and are almost invisible from the outside.

Reduce Draughts and Condensation

Most providers manufacture and install made-to-measure secondary glazing to ensure a perfect fit, preventing draughts and rattling. Minimizing air leakage, also keeps the surface temperature of your windows higher, reducing condensation and preventing mold from forming on your walls and ceilings.

Improved Security

Secondary glazing makes your windows more difficult to break, providing an extra layer of protection against forced entry. With sturdy frames and locking points, secondary glazing units can keep your home more secure.

Easy to Maintain

Compared to replacing your windows, secondary glazing requires minimal upkeep. Simply clean with warm soapy water, wipe with a clean cloth, apply some lubrication, and you’re good to go.

Secondary Glazing vs. Double Glazing

Although secondary glazing and double glazing offer similar benefits such as enhanced energy efficiency, weather resistance, security, and noise reduction, these two are very different in structure and installation.

If you’re wondering about the price difference, the next section will present the average cost of secondary glazing.

How Much Does Secondary Glazing Cost?

The cost of secondary glazing varies widely, depending on the type, size, and number of windows. While you can get magnetic secondary glazing kits for as little as £100 per window, the higher quality hinged or sliding types range between £350 and £550 per window. 

According to the Federation of Master Builders, for an average three-bedroom house with 8 to 10 windows, you can expect to spend between £1,200 and £5,500 for secondary glazing. For comparison, the average cost of double-glazing a three-bedroom house could reach £5,000 to £12,500.

If you’re working on a budget, refer to the table below to get an idea of the average cost of secondary glazing based on the type of unit.

Secondary Glazing Type	Cost per window	Total cost for 8-10 windows
Magnetic	£100–£200	£1,200–£1,500
Lift-out	£300	£2,400–£3,000
Horizontal sliding	£350–£500	£3,500–£5,000
Vertical sliding	£350–£500	£3,500–£5,000
Hinged	£350–£550	£3,500–£5,500

While cost is an important factor, the next section will help you look beyond the price and decide on the most suitable type of secondary glazing for your home.

Is Secondary Glazing Worth It?

Secondary glazing is the best choice if you want to experience the benefits of double glazing without spending as much or if you live in a listed building or conservation area where restrictions apply. 

However, unlike double glazing, which can increase a property’s value by 10%, secondary glazing may not necessarily add value to your home. Nevertheless, if your goal is to achieve an energy-efficient, comfortable, and secure home on a budget, secondary glazing is indeed worth installing.