French doors have long been a favourite feature in Australian homes — and it’s easy to see why. They create an elegant transition between indoor and outdoor living, flood interior spaces with natural light, and add undeniable character to a home’s aesthetic. But when those doors are single-glazed, all that charm comes with a hidden cost: heat gain, heat loss, and noise.
That’s exactly why more Perth homeowners are opting for double glazed French doors when they renovate or build. And if you’re considering the upgrade, there are a few things worth knowing before you commit to a contractor.
What Makes French Doors a Special Case for Glazing
French doors are predominantly glass. Unlike a standard door with a small decorative pane, French doors can be 70–80% glazed surface — which means their thermal and acoustic performance is almost entirely determined by the glass and frame combination.
A single-pane French door is essentially a large thermal hole in your wall. In Perth’s summer heat, a glass surface facing west or north can radiate significant warmth into your living space, forcing your air conditioning to work overtime. In winter, the same pane becomes a cold zone that draws warmth out of the room.
Double glazing changes this dynamic fundamentally. Two panes of glass with an insulating gas cavity between them break the direct heat transfer path. The result is a door that looks just as stunning as its single-glazed counterpart — but performs like a proper building element rather than a liability.
What to Ask Your Contractor
If you’re getting quotes, these are the questions that separate good double glazed French door installations from great ones:
1. What’s the U-value of the glazed unit? U-value measures how much heat passes through the glass assembly. Lower is better. A quality double glazed unit should have a U-value below 1.8 W/m²K. Ask for the spec sheet if you’re unsure.
2. Is low-E glass included or optional? Low-emissivity (low-E) glass has a microscopic metallic coating that reflects radiant heat while still allowing visible light through. In Perth’s climate, this is a meaningful upgrade — particularly for doors with northern or western exposure. Some suppliers include it as standard; others quote it as an add-on.
3. What frame material is being used? uPVC is the preferred option for most Perth residential installations. It doesn’t corrode, requires no painting, and doesn’t conduct heat the way aluminium does. For French doors — which often open directly to outdoor areas and are exposed to weather — the low-maintenance nature of uPVC is a practical advantage.
4. How are the doors sealed? Multi-point locking systems and compression seals are standard on quality French doors. Poor sealing is a common failure point — it undermines acoustic and thermal performance and can allow draughts and moisture ingress.
5. What’s included in the warranty? A reputable installer will warrant both the glazed unit and the frame separately. Ask specifically about seal failure (the fog or condensation that appears between panes when the unit fails) — quality units typically carry a 10-year unit warranty as a minimum.
What Does It Actually Cost?
Pricing for double glazed French doors in Perth varies based on size, glass specification, and frame finish. As a general guide, homeowners typically budget in the range of $1,500–$3,500 per pair for a quality supply-and-install, though larger custom configurations can exceed this.
The relevant comparison isn’t just cost-versus-cost against single glazing — it’s the cost against ongoing energy bills, comfort impact, and the value added to your property. Buyers in the current Perth market respond well to energy-efficient features, and French doors with double glazing are a visible, tangible selling point.
Finding the Right Installer
When shortlisting contractors, look for:
- Australian-made or Australian-tested product (not all glazing units are rated for our UV and heat conditions)
- Clear documentation of glass specifications (U-value, SHGC, STC rating)
- A physical showroom or sample you can view in person
- References or reviews from Perth-specific installations
The right contractor will walk you through the options without overselling unnecessary upgrades — and will give you a written spec alongside your quote so you can compare apples with apples.
Double glazed French doors are one of those home improvements where the aesthetic and practical benefits genuinely align. Get the specification right, and you’ll have doors that look beautiful and perform like they should.
Canon Double Glazing is a Perth-based specialist in double glazed windows, French doors, and uPVC glazing solutions for residential homes across Western Australia.
