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📋 Part of our Aluminium Window & Door Guide
Related: Aluminium Windows Buyer’s Guide · Aluminium Doors Guide

Buying aluminium windows and doors as separate products often creates specification gaps.

The profile may match, but the glazing may differ. The doors may use a different finish. One product may have thermal-break construction while another does not. Hardware capacity may also vary significantly between a standard window and a large sliding or bifold door.

For architects, contractors and procurement teams, the better approach is to treat the package as one fenestration specification, while still defining the performance requirements for each product type.

A complete package should cover six areas:

profile and thermal break, glazing, finish, hardware, performance and compliance evidence.

The objective is not simply to create a detailed specification. It is to create one that a manufacturer can actually quote, test, fabricate and deliver.

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Quick Summary

The key principle: specify the complete product configuration, not just the aluminium profile.

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Why Windows and Doors Should Be Specified Together

Windows and doors form part of the same building envelope, but they do not necessarily need identical construction.

A fixed window, a tilt-and-turn window, a French door and a 6-metre lift-and-slide door may belong to the same architectural system while having very different structural and hardware requirements.

What should remain consistent is the project-level specification:

• design intent
• finish
• glazing strategy
• thermal objectives
• environmental exposure
• performance criteria
• documentation requirements

Using a single supplier or compatible system family can simplify colour matching, glazing coordination, shop drawings and quality control.

But “same package” does not mean “same exact specification”.

That distinction is important.

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The 6 Items Most Often Missed

Most buyers remember the obvious items: dimensions, colour and product type.

The problems usually appear in the details.

1. Thermal-break construction

The specification should identify whether the system is thermally broken and which frame configuration is being proposed.

Do not specify only:

“PA66 thermal break.”

That identifies a material, not the thermal performance of the finished product.

2. Actual glazing build-up

“Double glazing” is not a complete glass specification.

State the proposed build-up, including where relevant:

• glass thickness
• number of panes
• cavity
• gas fill
• Low-E or solar-control coating
• spacer
• laminated or toughened glass
• safety requirements

3. Finish system

“A nice grey” is not a procurement specification.

Specify the applicable coating or anodising system, colour reference, gloss level where required, and environmental exposure.

For UK projects, BS EN 12206-1:2021 is a relevant standard for thermosetting powder coatings on aluminium used for architectural purposes. It covers aspects including substrate pre-treatment, coating powder, coating process and final product requirements.

4. Hardware capacity

Large doors place substantially higher loads on rollers, hinges, carriers and locks than standard windows.

The hardware must therefore be matched to:

panel size + panel weight + operating frequency + configuration.

5. Performance targets

Do not leave air, water, wind or thermal performance undefined.

A manufacturer cannot provide meaningful compliance evidence if the project never states what performance is required.

6. Test evidence

A certificate alone is not enough.

The procurement package should allow the buyer to trace:

requirement → tested product → tested configuration → report → supplied product

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Complete Aluminium Windows and Doors Specification Checklist

1. Profile and Frame

• Aluminium alloy specified
• Temper specified where relevant
• System manufacturer identified
• Frame depth specified
• Sash/leaf profile specified
• Mullion/transom configuration specified
• Thermal-break construction identified
• Threshold/sill configuration specified
• Drainage design reviewed
• Coupling profiles identified where used

For many architectural systems, 6063 aluminium alloys are commonly used for extruded profiles, but the alloy designation alone does not prove structural or thermal performance.

The complete profile geometry matters.

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2. Thermal Performance

For a UK project, this is where the original draft needs the biggest correction.

The specification should state a required whole-product U-value, rather than simply saying:

“U-Factor ≤1.8.”

England’s 2026 Approved Document L states that U-values should be assessed for the whole fabric element. For new dwellings, a window or door U-value is determined either through the BS EN ISO 12567-1 hot-box method or through calculation using the actual size and configuration under BS EN ISO 10077-1 and BS EN ISO 10077-2.

This means the specification should identify:

• Required whole-window/doorset U-value
• Calculation or test method
• Actual product dimensions
• Frame and sash configuration
• Threshold where applicable
• Couplers/extensions where applicable
• Glazing configuration
• Spacer specification

This is especially important for large aluminium doors because changing the panel size or frame-to-glass ratio can change the thermal result.

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3. Glass

A complete glazing specification should answer:

What glass? What thickness? What coating? What cavity? What gas? What safety classification?

Suggested checklist:

• Double or triple IGU
• Glass thickness
• Low-E coating
• Solar-control requirement where applicable
• Argon or other gas fill
• Spacer type
• Laminated glass where required
• Toughened glass where required
• Acoustic requirement
• Solar-performance target
• Visible-light requirement where applicable

Do not assume that “Low-E + argon” automatically equals a particular whole-window or whole-doorset U-value.

It is one part of the system.

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4. Finish

For a professional aluminium package, specify:

• Powder coating or anodising
• Applicable standard
• Colour reference
• Gloss level where required
• Interior/exterior finish
• Coastal exposure requirement
• Pretreatment system
• Touch-up procedure
• Colour consistency between windows and doors

BS EN 12206-1:2021 is particularly relevant when specifying architectural powder coating on aluminium in the UK.

Do not automatically specify AAMA 2605 just because the product is aluminium. AAMA coating specifications can be appropriate for particular project requirements or international procurement, but they should not replace the applicable UK specification.

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5. Hardware

Hardware is one of the most overlooked parts of a window and door package.

Windows

Specify:

• Handles
• Hinges
• Friction stays
• Restrictors
• Locking points
• Child-safety requirements where relevant

Doors

Specify:

• Hinges or rollers
• Carriers
• Track
• Multi-point locking where required
• Cylinders
• Pull handles
• Door closers where relevant
• Panel/leaf weight capacity
• Replacement hardware availability

For large sliding or folding doors, ask for the manufacturer’s documented hardware capacity for the actual configuration, not merely a catalogue maximum for another model.

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6. Air, Water and Wind Performance

This is another area where the original universal values should be removed.

Do not write:

Air leakage = 0.07 CFM/ft²

or:

Water = 15 psf

unless those are the actual project requirements.

For UK products, commonly referenced European test and classification standards include:

• BS EN 1026 — air permeability test
• BS EN 12207 — air permeability classification
• BS EN 1027 — watertightness test
• BS EN 12208 — watertightness classification
• BS EN 12211 — resistance to wind load test
• BS EN 12210 — wind-load classification

For projects using US or international test protocols, ASTM methods may instead be specified. ASTM E283/E283M-26, for example, is the current ASTM test method for air leakage through exterior windows, skylights, curtain walls and doors under specified pressure differences.

The important point is:

the test method tells you how the product was tested; the project specification tells you what performance is required.

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7. Standards and Compliance Evidence

BS EN 14351-1:2006+A2:2016 remains a current BSI standard for windows and external pedestrian doorsets and covers material-independent performance characteristics within its scope. However, it is not a universal statement that every aspect of a project is compliant. BSI also notes that products covered by the standard are not assessed for structural applications and lists exclusions such as curtain walling and certain industrial/commercial doors.

Therefore, your checklist should say:

• Applicable product standard identified
• Applicable test standards identified
• Performance classification identified
• Test report available
• Tested size identified
• Tested configuration identified
• Glazing configuration identified
• Hardware configuration identified
• Manufacturer/model identified
• Certification scope reviewed

This is far more reliable than simply asking:

“Is the product CE certified?”

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What a Good UK Specification Looks Like

Instead of publishing one universal set of numbers, build the specification around project requirements.

This gives the manufacturer something they can actually price and build against.

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Project Specification Example

A real project schedule might look like this:

Notice that the package is unified at project level while the individual products retain different technical requirements.

That is how a real window-and-door schedule should work.

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Do Windows and Doors Need Identical Specifications?

No.

They should have coordinated specifications, not necessarily identical ones.

A window may require a particular U-value and ventilation provision.

A lift-and-slide door may require a completely different roller system and structural rating because its sash is substantially heavier.

A front entrance door may need a different locking and threshold specification.

The common elements should usually be:

architectural finish + glazing strategy + thermal objective + project compliance framework + documentation requirements.

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Decision Guide: How to Build the Package

This sequence prevents the common mistake of selecting the profile first and trying to solve performance later.

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What to Send an Aluminium Window and Door Manufacturer

For a serious quotation, provide:

A manufacturer that receives only:

“Please quote aluminium windows and doors.”

cannot produce a technically comparable quotation.

The more useful request is:

“Quote this opening schedule against the attached performance specification and provide the corresponding test/calculation documentation.”

That is a B2B procurement request.

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Aluminium Windows and Doors Cost

The cost of a complete package depends on much more than the aluminium profile.

Key cost drivers include:

• system type
• opening dimensions
• number of units
• thermal-break construction
• glazing
• hardware
• finish
• thresholds
• engineering
• testing
• installation
• shipping

The same nominal aluminium window size can produce significantly different prices depending on the glass, hardware and performance specification.

For this reason, a reliable procurement comparison should use:

same dimensions + same glazing + same performance + same hardware scope + same finish + same installation scope.

Otherwise, the lowest quotation may simply be the least complete quotation.

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Quality-Control Checklist Before Production

Before approving fabrication, verify:

• Approved shop drawings
• Final opening dimensions
• Frame and sash configuration
• Glazing make-up
• Safety glass requirements
• Thermal performance calculation/report
• Air/water/wind evidence
• Hardware schedule
• Colour and finish sample
• Drainage details
• Anchorage details
• Installation method
• Revision-controlled documentation

This should be a pre-production gate, not something checked after the products arrive on site.

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Frequently Asked Questions

What should an aluminium windows and doors specification include?

A complete specification should cover the frame system, thermal-break construction, glazing, finish, hardware, air/water/wind performance, applicable standards, testing and installation requirements.

How do I specify aluminium windows and doors?

Start with the project and opening requirements, then define the product type, thermal target, glazing, hardware, weather performance, finish and compliance evidence. For UK projects, the complete product configuration matters when determining thermal performance.

What U-value should aluminium windows and doors have?

There is no single universal value for every UK project. The required target depends on building type, regulatory pathway, project energy strategy and product configuration. In England’s 2026 guidance, window and door U-values are assessed for the whole element and can be determined by testing or calculation using the actual configuration.

Do aluminium windows and doors need the same glazing?

Not necessarily. The glazing should be coordinated with the building’s energy, solar, acoustic and safety requirements. Large doors may also require a different glass thickness or construction because of panel size and weight.

Do aluminium windows and doors need the same finish?

They should normally be coordinated for appearance, but the finish specification must still suit the exposure and product application. BS EN 12206-1:2021 provides requirements for architectural powder coatings on aluminium and aluminium alloys.

Is EN 14351-1 enough to prove compliance?

No. EN 14351-1 is an important product standard within its scope, but it does not establish every structural, energy, security, fire or project-specific requirement. The buyer should verify the actual test reports, calculations and certification scope.

Should I specify air and water performance with fixed numbers?

Only when those numbers come from the project requirement or applicable product classification. ASTM E283/E283M-26, for example, is a test method for determining air leakage; the test method itself is not a universal maximum allowable leakage value.

What documents should a manufacturer provide?

At minimum, request the relevant product data, test reports, thermal calculations where applicable, drawings and hardware information. The documentation should allow the quoted configuration to be traced back to the claimed performance.

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Final Specification Checklist

Before issuing the package for quotation, confirm:

Profile → Thermal Break → Glazing → Finish → Hardware → Air → Water → Wind → Thermal → Standards → Test Evidence → Installation

If any one of those remains undefined, the package is not yet a complete technical specification.

The objective is not to specify the most expensive aluminium window and door system.

The objective is to specify the lowest-cost system that can demonstrably meet the project’s architectural, thermal, structural, weather and regulatory requirements.

Request an Aluminium Window & Door Package Specification →