You have received an aluminium window quote, perhaps from Inso, perhaps from a competitor, and now you are staring at a column of codes, abbreviations, and numbers that do not quite explain themselves. That is not unusual. Window quotes vary enormously in how much detail they provide, and a vague quote is not just confusing, it is a risk. The less a quote specifies, the more room there is for substitutions, hidden costs, and disappointed expectations once installation day arrives.
A good aluminium window quote should do one clear thing: remove ambiguity. It should list each window individually, with its size, style, frame series, glass type, colour, and hardware all named explicitly. VAT and installation should appear as separate line items, not buried in a rounded total. If your quote does not do that, this guide will help you ask for what is missing.
Table of Contents
Understanding What a Window Quote Should Include
Before you compare prices, confirm that both quotes are actually quoting the same thing. This sounds obvious, but it is the single most common mistake homeowners make. A quote for a 6mm clear glass window and a quote for a 6.38mm laminated safety glass window may show very different prices, and both can legitimately be called “a window quote.”
At minimum, every line item in a transparent quote should specify:
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The window code or reference (which encodes size and style)
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The frame series or profile range
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The glass specification
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The colour or powder coat finish
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The quantity
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The unit price and line total
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Whether VAT is included or excluded
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Whether installation is included or quoted separately
If any of those elements are missing, you cannot compare that quote fairly against another one. You are not comparing windows; you are comparing assumptions.
What Window Codes Like 0606T Actually Mean
Window codes look cryptic, but they follow a consistent logic once you know the key. Take the code 0606T as an example. The first two digits refer to the width in hundreds of millimetres, so “06” means 600mm. The second pair of digits refers to the height, so another “06” means 600mm. The letter at the end indicates the window style: in this case, T stands for a top-hung or awning configuration.
Here is a sample quote line, modelled on the format used in Inso’s pricing guide, with each part explained:
|
Code |
Size |
Style |
Series |
Glass |
Colour |
Unit Price (excl. VAT) |
|---|---|---|---|---|---|---|
|
0906T |
900 x 600mm |
Top-hung awning |
Eco 40 |
6mm Clear |
Matt Black |
R2,850 |
Code: The shorthand reference. 09 = 900mm wide, 06 = 600mm high, T = top-hung.
Series: The frame profile. Different series have different wall depths, thermal properties, and maximum spanning capabilities. A heavier series costs more but performs better on large openings.
Glass: The specification of the glazing unit. “6mm Clear” is standard. “6.38mm Laminated” or “4/12/4 Double Glazed” indicate upgraded specifications with different cost and performance implications.
Colour: Aluminium windows are powder coated. The colour is baked on and durable, but non-standard colours sometimes carry a surcharge. Always confirm whether your chosen colour is standard or a special order.
Common style suffixes you may encounter include C for casement, S for sliding, F for fixed, and T for top-hung. If your quote uses a suffix you do not recognise, ask. You have every right to a plain-language explanation before you commit.
What Glass Specification Your Quote Should Name
Glass is where quotes diverge most sharply, and where homeowners lose the most value without realising it. The glass line item is not a formality. It determines your window’s safety rating, thermal performance, acoustic properties, and compliance with SANS building regulations for certain applications.
A quote that simply says “glass included” without specifying the type is not giving you enough information. Here is what to look for:
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Thickness: 4mm, 5mm, or 6mm are common. Thicker glass is heavier and stronger, and is required above certain spanning widths.
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Type: Clear, obscure (frosted), tinted, reflective, laminated, or tempered (toughened). Wet areas such as bathrooms typically require safety glass by regulation.
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Double glazing: Written as 4/12/4 or similar, this refers to the two glass panes and the air or argon gap between them. If energy efficiency or noise reduction matters to you, confirm whether double glazing is quoted or assumed.
If you are comparing two quotes and one specifies 6mm toughened glass while the other lists 4mm clear, the price difference between them is not just a supplier margin. It is a product difference.
Is VAT Included, and Is Installation a Separate Cost
These two questions catch people out more than any other. In South Africa, VAT at 15% adds a meaningful amount to any window order, and a quote that excludes it can look far more competitive than it actually is.
Always check whether the totals on your quote are shown as VAT exclusive, VAT inclusive, or split out as a subtotal with VAT added below. If the quote does not say, ask before you compare it to anything else.
Installation is a separate question entirely. Some suppliers quote supply only. Others include installation but do not itemise it, which makes it impossible to assess whether you are getting good value on the fitting. Best practice is a quote that shows the supply cost, the installation cost, and VAT as three distinct figures. That way, if you already have a trusted installer, you can make an informed decision about whether to use the supplier’s team or your own.
Also check whether the installation cost includes plastering, sealing, and making good around the frame, or whether that is assumed to be the client’s responsibility. It is a small detail that becomes a large frustration.
How to Compare Two Aluminium Window Quotes Fairly
Put both quotes into a simple comparison table before you make any decisions. The columns should be: item code, size, style, series, glass, colour, quantity, unit price excluding VAT, and installation status. Fill in every cell. Where a quote does not specify something, mark it as unknown and go back to that supplier with a direct question.
Once you can see the two quotes side by side on the same terms, the comparison becomes straightforward. You are looking for three things: whether the products are genuinely equivalent, whether the pricing is transparent, and whether the supplier has answered your questions clearly and without deflection.
Price per window is a useful metric, but only after you have confirmed the specifications match. A cheaper window in a lighter series with thinner glass is not the same product as a more expensive one in a heavier series with safety glazing. Knowing what you are comparing is the whole point of this exercise.
For more detail on what typical aluminium window pricing looks like across sizes and styles, the Aluminium Windows Pricing Guide gives a clear reference point by size and configuration.
Red Flags in an Aluminium Window Quote
Most suppliers are straightforward, but a few patterns in a quote are worth treating with caution.
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No itemisation: A single lump sum for “10 windows, supply and install” gives you nothing to verify and nothing to dispute if the product delivered does not match your expectation.
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No glass specification: As discussed above, this is a meaningful omission, not a minor one.
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No VAT disclosure: A quote that does not state whether VAT is included or excluded is not a complete quote.
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Unusually short validity: A quote valid for 48 hours is pressure, not policy. Legitimate suppliers understand that homeowners need time to compare and decide.
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Vague lead times: “Delivery in a few weeks” is not a lead time. Ask for a written estimated lead time and installation date.
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No mention of SANS compliance: Windows installed in South Africa should comply with relevant SANS standards. If a supplier cannot confirm this when asked, that is worth noting.
Your Checklist Before Accepting Any Window Quote
Work through these questions before you sign anything. If you cannot answer yes to all of them, go back to the supplier for clarification.
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Does the quote list every window individually, with its code, size, and style?
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Is the frame series or profile range named?
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Is the glass type and thickness specified for each item?
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Is the colour or powder coat finish confirmed in writing?
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Does the quote state clearly whether VAT is included or excluded?
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Is installation quoted separately, with a clear scope of what it covers?
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Is there a written lead time and an estimated installation date?
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Are hardware and fittings included, or quoted as extras?
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What is the warranty on the frames, glass, and installation workmanship?
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What happens if a window is damaged during delivery or installation?
A supplier who welcomes these questions is one worth working with. A supplier who becomes evasive or impatient is telling you something useful before any money has changed hands.
If you are considering casement windows specifically, which are one of the most popular styles for both ventilation and clean sightlines, the casement window range at Inso shows the configurations available and how they are specified in a quote.
Get a Quote That Shows You Everything
Reading a window quote well is not about being suspicious of suppliers. It is about being informed enough to make a confident decision, and to hold whoever you choose accountable to what was agreed in writing. The more clearly a quote is written, the easier that accountability becomes for everyone involved.
If you would like to see what a fully itemised aluminium window quote looks like, get in touch with Inso for a transparent, itemised quote with every specification named. No lump sums, no guesswork.
Frequently Asked Questions
What does the code on my window quote mean?
Window codes typically encode the size and style of the window. The first two digits represent the width in hundreds of millimetres, the second two represent the height, and the letter at the end indicates the opening style, such as T for top-hung, C for casement, or S for sliding.
Should VAT be included in my window quote in South Africa?
VAT should be disclosed clearly, either included in the totals or shown as a separate line item added to a subtotal. A quote that does not state its VAT treatment is incomplete. Always ask before comparing prices from different suppliers.
Is installation normally included in an aluminium window quote?
Not always. Some suppliers quote supply only, others include installation. The safest approach is a quote that shows supply and installation as separate figures so you can assess both clearly. Confirm whether the installation cost also covers sealing and making good around the frame.
How do I compare two window quotes from different suppliers?
Build a side-by-side table with the same columns for both quotes: size, style, series, glass, colour, unit price excluding VAT, and installation status. Only compare total prices once you have confirmed that the specifications in each quote are genuinely equivalent.
What glass should my aluminium windows have?
This depends on the application. Standard residential windows typically use 6mm clear glass. Wet areas such as bathrooms require safety glass (toughened or laminated) under SANS regulations. If noise or thermal performance is a priority, double glazing is worth specifying. Always confirm the glass type in writing before accepting a quote.
What is the difference between the frame series options on a quote?
The frame series refers to the aluminium profile used to build the window frame. Different series have different wall depths, strength ratings, and maximum spanning widths. A heavier series is better suited to large openings and tends to carry a higher price. Ask your supplier which series is appropriate for your specific opening sizes and building type.
