The Window Efficiency Debate
In the quest for energy efficiency and comfort, homeowners often find themselves at a crossroads: should they opt for secondary glazing or invest even more in upgrading their existing windows by swapping the old glass for some modern double glazing? Both options offer promise to improve insulation and reduce energy bills, but they are significantly different in their approaches and budgets. This guide explores the nuances of each solution to help you decide which is best for your home.
What Each Solution Actually Is
Double Glazing
While double-glazed windows (whether PVCu or wood frames) is especially popular for new builds and modern homes because it effectively uses well-developed technology to maintain indoor temperatures, unfortunately, for owners of Listed Properties or those who enjoy historic character, replacing the windows, rather than just the glass, is usually not an option. Double glazing an older window (as opposed to replacing the window itself, frame-and-all) involves replacing the existing window glass with new “units” that have two panes of glass separated by a sealed ‘air’ gap. This air gap acts as an insulator, reducing heat loss and improving energy efficiency, and likely includes both an inert gas (so not actually ‘air’) and an invisible coating on the glass to bounce radiant energy back into your room, a bit like a one-way mirror that works for infra-red light only.
Secondary Glazing
Secondary glazing, on the other hand, is an additional layer or system installed on the inside of an existing window frame. It is particularly beneficial for period properties where maintaining the original windows is crucial. Secondary glazing enhances insulation without changing the building’s external appearance. Nothing is changed on the outside, not even the single glazing. For these reasons, Conservation Officers are generally in favour of secondary glazing, and the route to any approvals, for example, Listed Building Consent, is often short or not required.
Cost Comparison (Upfront & Lifetime)
When it comes to cost, secondary glazing typically emerges as the more affordable option. The initial investment per window is generally lower compared to full-frame double glazing. For an average house, secondary glazing can significantly reduce total project costs, making it an attractive choice for budget-conscious homeowners.
Thermal Performance & Energy Savings
Double glazing generally offers superior insulation – if it is an option. Both secondary and double glazing improve thermal efficiency, but there are differences in their effectiveness. However, secondary glazing can still provide adequate thermal improvements, firstly because it is rarely disallowed and secondly in older homes where the primary goal is to retain the character of the windows. In such cases, secondary glazing can be "good enough" to meet energy-saving goals.
Noise Reduction & Comfort
One of the standout benefits of secondary glazing is its ability to reduce noise. The larger gap between the original window and the secondary pane can outperform double glazing in soundproofing. This makes secondary glazing an excellent choice for homes in noisy environments, such as city centres or near busy roads.
Installation, Disruption & Practicality
The installation process for secondary glazing is typically quicker and less disruptive than that of double glazing. It does not require full-frame replacement nor extensive surgery on the window, making it a practical choice for those looking to minimise disruption. Double glazing, while highly effective, requires more extensive installation work, which is undesirable if you are living in the property and the weather isn’t ideal for it.
Aesthetic & Heritage Considerations
For listed or conservation homes, maintaining the aesthetic integrity of the property is paramount. Secondary glazing, especially magnetic options such as Extraglaze, provides a discreet solution that preserves the original look of your windows. This makes it an ideal choice for heritage properties where alterations are restricted.
Maintenance & Flexibility
Secondary glazing panels offer flexibility in maintenance. Secondary glazing panels can be removed seasonally or for cleaning, offering a convenience that double glazing might not. This feature is particularly useful in homes where window accessibility is a concern.
Drawbacks & When Double Glazing Makes Sense
While secondary glazing offers numerous benefits, there are scenarios where double glazing might be more appropriate. For new builds or homes with high thermal demands, double glazing can provide maximum efficiency. It may also improve resale value by meeting modern building standards.
Thinking About Extraglaze Secondary Glazing?
In conclusion, both secondary and double glazing have their merits. However, if cost, heritage preservation, and noise control are your priorities, secondary glazing is a compelling choice. It offers a balance of efficiency and practicality, especially in older homes. Conversely, for new builds or when maximum thermal performance is essential, double glazing may be the better option. Weigh your specific needs and circumstances to make an informed choice.
