Aluminium French Doors: What You Need to Know Before You Purchase

French doors have this way of making spaces feel bigger and more connected - whether you're opening up to a deck, creating flow between living areas, or just letting more light flood in.

Aluminium versions have become the go-to choice in New Zealand, and for good reason. Here's what makes them work, what to watch for, and how to spec them properly for your project.

Why Aluminium for French Doors?

Timber French doors look classic, but they're high maintenance in our UV-intense, moisture-prone climate. uPVC is cheaper but can feel chunky and lacks the clean lines most people want.

Aluminium hits the sweet spot:

• Slim sightlines that maximise glass area

• Zero rot or warping - even in coastal areas

• Powder-coated finishes that last 15+ years without repainting

• Structural strength for larger openings without needing thick frames

Modern aluminium French doors also come with thermal breaks - a polyamide strip inside the frame that stops heat transfer. Without it, you get condensation and cold spots. Make sure any system you're considering has this built in.

Internal vs External French Doors

External Aluminium French Doors

These need to meet stricter weathertightness and security standards. Look for:

• Multi-point locking (5+ points is standard)

• Compression seals, not just brush strips

• Minimum 6mm toughened glass (often 6.38mm laminated for safety)

• Compliant with Building Code wind and water ratings for your area

External doors also need proper thresholds. The Building Performance website has good info on weathertightness requirements.

Typical cost: $3,500–$6,500 for a standard 2.1m x 1.8m pair installed.

Internal French Doors

More straightforward since they don't face weather or security concerns. You can go slimmer on the frames and use standard (not toughened) glass if you want.

They're great for:

• Separating living and dining without closing off light

• Creating flexible office spaces

• Adding a sense of openness to smaller homes

Typical cost: $2,200–$4,000 for a standard pair installed.

Black Aluminium French Doors: The Design Favourite

Black aluminium door frames have taken over in the last five years - and it's not hard to see why. They look sharp, suit both modern and traditional homes, and create strong contrast against light walls or timber.

A few things to know:

Black powder coat finishes absorb more heat than lighter colours. In direct sun, the frames can get warm to touch (though the glass handles most of the heat load anyway). It's not a dealbreaker, but if your doors face north or west with no shading, consider it.

Black also shows fingerprints and dust more than grey or white. Not a huge issue, but worth knowing if you have young kids.

Warm White Pearl

Ironsand Flat

Charcoal Matt

Colour alternatives worth considering:

• Warm White Pearl: Timeless and practical

• Ironsand Flat: Dark metallic grey with texture

• Charcoal Matt: Almost as dark, slightly softer

Most manufacturers offer 200+ colours, so you're not limited to black - but it does look good.

Glass Options for French Doors

Standard is 6mm toughened or 6.38mm laminated, but there's flexibility depending on your needs:

• Obscure or frosted glass: For bathrooms or bedrooms where you want light but privacy. Satin finish works better than patterned options, which can date quickly.

• Low-E double glazing: Essential if your doors face south or you're in a colder region. Cuts heat loss by 30-40% compared to standard glass.

• Acoustic glass: If your doors open to a busy street or noisy neighbours. Adds $300–$600 but genuinely works.

• Georgian bars or colonial grilles: Some people love the traditional divided-light look. Just know that maintenance is harder (cleaning between the bars), and it can reduce glass area.

Getting the Opening Size Right

French doors need enough width to actually feel worth it. A pair that's only 1.4m wide (700mm per door) feels cramped onc

e you account for the frames.

Recommended minimums:

• Internal doors: 1.6m wide (800mm per leaf)

• External doors to deck/patio: 1.8–2.1m wide

• Main living area access: 2.4m+ if space allows

For openings wider than 2.4m, consider bifold or sliding options instead—French doors get heavy and awkward beyond that size.

Door Swing: Think It Through

French doors need clearance to swing open. Obvious, but people forget how much space that actually eats up.

Typical door swing: 90 degrees is standard, but you can spec 180-degree hinges if you want them flat against walls.

Consider:

• Furniture placement (nothing blocking the swing path)

• Wind catch (external doors need holdbacks or they'll slam)

• Traffic flow (do people need to walk through when doors are open?)

For tight spaces, sliding French doors exist—though they're more expensive and have different hardware requirements.

Hardware That Actually Matters

Cheap handles and hinges will fail. French doors get used constantly, so invest in quality:

• Hinges: Stainless steel, concealed where possible. 3 per door minimum for standard height; 4 for doors over 2.2m.

• Handles: Choose lever handles over knobs—easier to operate and more accessible. D-pulls or offset handles work well for modern designs.

• Locks: Multi-point locking is non-negotiable for external doors. For internal, a simple latch is fine unless you need sound isolation or privacy.

Weatherproofing External French Doors

Even well-made aluminium French doors need proper installation to stay weathertight.

What to check:

• Thresholds: Must have integrated drainage channels. Low-profile thresholds are great for accessibility but need perfect leveling.

• Seals: Compression seals on all edges. Brush seals alone won't cut it in heavy rain.

• Flashing: Your installer should use head flashing and jamb seals that tie into your building wrap. This isn't optional - it's Building Code.

The Building Performance website has E2/AS1 compliance guides that cover installation details. If your installer doesn't mention these, find someone else.

Cost Breakdown: What You're Actually Paying For

For a standard 2.1m x 1.8m external aluminium French door pair:

• Frames and glass: $2,200–$3,800

• Hardware (hinges, handles, locks): $400–$700

• Installation (including flashing): $800–$1,200

• Building consent (if required): $300–$600

Total: $3,700–$6,300 depending on specification.

Add 20 - 30% for:

• Black or custom colours

• Low-E or acoustic glass

• Non-standard sizes

• Difficult access (upstairs, scaffolding needed)

Design Tips from Real Projects

• Use them to frame views: Position French doors to capture the best outlook - not just where the previous door was.

• Match your windows: Same frame colour, profile, and glass spec creates cohesion. Mixing systems looks disjointed.

• Think about furniture: Make sure your sofa or dining table doesn't block the doors when open.

• Consider built-in blinds: Slimline blinds between the glass panes are low-maintenance and clean-looking - though they add $600–$900 to the cost.

Common Mistakes to Avoid

• Going too narrow: A cramped door opening defeats the purpose. If space is tight, a single wider door or slider works better.

• Skimping on seals: External doors with basic brush seals will leak. It's not if, it's when.

• Ignoring thermal performance: Non-thermally broken frames will condense heavily in winter. You'll wipe them down constantly.

• Forgetting sun angles: North and west-facing French doors without shading can overheat rooms in summer. Plan for blinds, pergolas, or eaves.

What About APL Window Solutions Systems?

At Phoenix Windows & Doors, we use proven systems from APL Window Solutions, including Altherm, specifically engineered for New Zealand conditions - seismic activity, high UV exposure, strong winds, and extreme weather.

These systems are tested to NZBC requirements and feature proper thermal breaks, quality seals, and long warranties. Choosing a licensed manufacturer like Phoenix means you’re investing in proven performance, not experimental products. Contact us here.

Making the Choice

French doors aren't the only option. Sliding doors offer wider openings, bifolding doors stack away completely, and pivot doors make a statement. But if you want:

• Classic aesthetic with modern performance

• Reliable weathertightness

• Easy operation without tracks or complex hardware

Then aluminium French doors are hard to beat.

Just make sure you're working with someone who understands installation details, thermal performance, and Building Code compliance. The door itself is only half the job - how it's fitted determines whether it performs or fails.

For more on choosing entrance doors or complementary window systems, check out our other guides.