Yes, in many cases. If your aluminium frames are sound and deep enough to take a sealed double glazed unit (or a slim heritage unit), a glazier can replace the single panes and adapt the glazing beads for much less than new windows. Older, shallow or damaged frames are usually better suited to secondary glazing or full replacement.
So, you’re considering changing your windows from single glazing to double. Good choice! But what now?
We’ll take you through why retrofit double-glazing aluminium windows are the right choice to replace the existing windows in your home.
Without further ado, let’s get to it!
What Are the Problems With Single Glazed Windows?
Single glazed windows lose around four times as much heat as modern double glazing, suffer badly from condensation, let in more noise and are easier to break. They are cheaper to buy but cost more over time in energy bills and damp-related repairs.
Durability: Single-glazed glass is not very durable, meaning they aren’t hardy when it comes to wear and tear. You need windows that can handle harsh weather and maintain their structure if something hits them - having a panic attack every time a child kicks a ball in your garden is no way to live.
Insulation: A single-glazed window isn’t very good insulation. You want windows that maintain heat in the home to lower your energy consumption and energy bill, especially as single glazing loses around four times as much heat as modern double glazing.
Condensation: Warm indoor air hits the cold surface of single glazing, which causes condensation problems as moisture forms on the window and other cool surfaces. While this is not an immediate risk, the condensation will gradually affect plaster and paint, and cause wood to decompose. It costs you more money to replace the window and repair the damage.
Security Risk: A single pane or one pane of glass is easier to break, which means weaker security than other glazing options.
Cost: From the outset, single-glazed windows are cheaper than double or triple glazing. However, in the long run, single-glazed windows cost more if you consider the loss of money on energy bills and the replacement rate for things like condensation damage.
What Are the Benefits of Retrofitting Double Glazing?
Retrofitting double glazing improves heat retention, reduces condensation and outside noise, makes windows harder to break and can add appeal when you sell – usually for less than the cost of new windows. See how glazing affects window U-values.
Now, let’s see why double-glazing is a good option for replacing your existing windows.
Thermal efficiency: The biggest advantage of double glazing is improved heat retention, especially compared with the thermal inefficiencies of single-glazed windows. Double-glazing adds a sealed gap between panes that creates an insulating layer, so there is less heat loss in winter and the retrofit process can improve energy efficiency significantly. This improved insulation can noticeably cut energy bills and reduce reliance on air conditioning in warmer periods.
Noise reduction: External noise is a big issue for some, especially if you live on a busy road. Fortunately, retrofit double-glazing can address this problem with stronger sound insulation. The two panes of glass trap noise outside and keep your noise in. Worrying about your music being too loud or the baby having an off day is a recipe for a tension headache.
Increased property value: Home buyers look for well-made windows and doors that look great and keep the house warm. Double glazing your aluminium windows, and pairing them with modern aluminium bifold doors, is one way to improve your home's appeal.
Increased security: Double glazing is harder to break than a single pane and helps protect against break-ins, especially combined with a strong aluminium frame. Learn more in what are aluminium windows?
Can You Double Glaze Existing Aluminium Windows?
The good news? You can often retrofit double glazing into the existing windows in a newer home, and it’s usually more cost-effective than buying new windows, with savings of around 30–40%. So don’t worry about going out and buying half the hardware store; the process is usually straightforward.
If your home is relatively new, your windows are often ready for the upgrade. Retrofitting usually means removing the existing glass and fitting new double glazed glass into the frame rather than replacing the whole unit, and it can be done on most existing windows. That said, not all existing windows are suitable, especially if the frames are older or weak.
However, things can get a bit more complicated if your home is older with more delicate and fragile window frames. In some cases, heritage windows or original windows are better suited to secondary glazing than full double-glazing replacement.
If you have an older building, secondary glazing is often the better option. It adds an independent pane on the inside of the existing window, giving a big improvement in insulation and noise reduction with little disruption and no change to the outside appearance – ideal for listed or conservation-area homes.
We've also got tips on sealing aluminium doors and windows and draught proofing aluminium windows.
Some of our products include:
Double glazed units are heavier than single panes, so you need to be sure your existing frames, hinges and stays are strong enough for retrofit units.
Aluminium is highly durable and can hold the weight needed for new double-glazed glass, which is one of the main reasons we use it for our products. During installation, it may also be worth checking or replacing rubber seals and, where relevant, adding a thermal break to improve heat retention levels.
Retrofit Double Glazing FAQs
Are double-glazed windows better than single-glazed?
Yes, double-glazing is better in the long run. It is much more durable, insulating, and secure than single-glazed windows.
Can I retrofit my existing windows at home?
Look, you could try anything at home, but we wouldn’t recommend it in this case. Windows and glass are a speciality for a reason, and retrofit double glazing installation is specialist work rather than a DIY job. If anyone could do it, they would. It takes a lot of skill and training to fit windows correctly.
Is double-glazing existing windows expensive?
If we look at the price difference, double-glazing is more expensive than single-glazing. However, retrofitting can cost 30–40% less than new windows, with long-term savings coming from improved energy efficiency and lower energy bills.
What is the difference between secondary glazing and double glazing?
Double glazing replaces the single pane with a sealed unit of two panes inside the existing frame. Secondary glazing leaves the original window in place and adds a separate inner pane in its own slim frame. Secondary glazing is cheaper and reversible, so it suits listed buildings; double glazing performs better and is less visible.
Can you double glaze existing sash windows?
Often, yes. Slim heritage double glazed units or ultra-thin vacuum glazing can fit many existing sash frames, although the sashes may need re-weighting for the extra glass. Where frames can't take new units, secondary glazing is the usual alternative.
Do you need building regulations approval to replace just the glass?
Generally no. Replacing only the glass in an existing frame is not normally notifiable building work, whereas replacing the whole window is. If you're unsure, or the property is listed, check with your local authority first.
