Timber vs Aluminum Windows in NZ: Insulation, Condensation & Comfort (2025 Guide)
Replacing windows is one of the most effective ways to improve comfort, warmth and energy efficiency in a New Zealand home. But most people focus only on the glass — when in reality, the window frame material plays a major role in insulation and condensation control.
This 2025 guide explains the real differences between timber and aluminium windows under New Zealand climate and building standards, helping homeowners, builders and architects make fully informed decisions for renovations and new builds.
Replacing windows is one of the most effective ways to improve comfort, warmth and energy efficiency in a New Zealand home. But most people focus only on the glass — when in reality, the window frame material plays a major role in insulation and condensation control.
This 2025 guide explains the real differences between timber and aluminium windows under New Zealand climate and building standards, helping homeowners, builders and architects make fully informed decisions for renovations and new builds.
1. Timber provides the best insulation for New Zealand homes
When comparing window frame materials, the biggest difference is how much heat each material conducts. This directly affects comfort, warmth and energy efficiency.
Standard aluminium frames conduct heat very easily — they quickly transfer outdoor temperature inside, making homes colder in winter and hotter in summer.
This results in lower overall insulation performance, even with good double glazing.
Thermally broken aluminium improves performance — a “thermal break” reduces heat transfer through the frame.
This allows aluminium to meet the minimum H1 energy code when combined with high-performance glass, but it still performs below timber overall.
Timber is naturally insulating — it slows heat transfer between inside and outside, helping the home stay warmer, drier and more stable in temperature.
Timber consistently offers the highest insulation performance when paired with modern double glazing.
Because the frame accounts for 15–25% of the total window area, upgrading the frame material can dramatically improve the real-world warmth and comfort of the home.
2. Timber significantly reduces condensation and mould
Condensation forms when warm indoor air meets a cold surface. Aluminium frames get cold quickly, promoting condensation, especially in bedrooms and bathrooms.
Timber frames retain heat and stay warmer internally, which:
✔ reduces visible condensation
✔ protects paint and seals
✔ prevents mould growth and sill damage
✔ creates a drier, healthier home
For families and asthma-sensitive homes, this is a major comfort and health benefit.
3. Pricing has changed — aluminium is no longer the “cheap” option
Historically, aluminium was significantly cheaper. But under the updated H1 Energy Efficiency requirements, standard aluminum no longer meets insulation performance in most new builds.
To comply, aluminum must now be thermally broken, which:
adds cost
adds plastic components
adds manufacturing complexity
As a result:
The price gap between aluminium and timber has reduced significantly.
Today, homeowners are comparing thermally broken aluminium vs timber, not “cheap aluminium vs timber.”
4. Installation, flashings and weathertightness — who is responsible for what
Windows are only one part of a weatherproof wall assembly.
Weathertightness is achieved through the cladding, flashings, building wrap and sealing, not the joinery alone.
We do not supply flashings, because they are specific to the cladding system and building consent drawings. The builder is responsible for:
installing sill and head flashings
integrating the frame with the building wrap
sealants and finishing systems
following E2/AS1 and the consented details
Our role is to supply joinery that meets NZS 4211 — Performance of Windows.
Correct installation and finishing are required to achieve full weathertightness.
5. Glazing options — the best insulation comes from the right combination
We manufacture joinery to accept a full range of glazing options:
Low-E double glazing
Argon gas fill
Safety glass (toughened/laminated)
Acoustic glazing
Privacy glass
The best thermal performance comes from combining:
an insulating frame + high-performance glass
6. Protecting your investment — painting and maintenance
To protect performance and warranty:
Before exposure to weather:
Apply two top coats of quality exterior paint or film-forming clear finish
Paint all six surfaces — front, back, top, bottom and both sides
Prime any areas where timber is removed for hardware
Ongoing care:
Clean annually
Recoat when early signs of paint wear appear
Avoid dark exterior colours (LRV < 45) on sun-exposed elevations
With proper finishing and maintenance, timber joinery delivers decades of reliable performance.
Ready to compare options or get pricing?
Email your plans or measurements for a fast quote: info@dando.net.nz
If you’re comparing timber and aluminum joinery and want to understand the performance and price differences for your home, our team is here to help.
We manufacture NZS 4211 tested, JMF-certified, double-glazed timber joinery for homes across New Zealand and were recognised by JMF in 2025 as the largest NZ timber window and door producer nationwide.
📍 Auckland showroom
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Timber vs Aluminium Windows in NZ – FAQs
Are timber windows warmer than aluminium in New Zealand homes?
Yes. Timber is a natural insulator, so timber window frames conduct far less heat than standard aluminium. This helps keep more warmth inside in winter and reduces overheating from sun-exposed frames in summer.
Do timber windows help reduce condensation?
Timber frames stay much closer to the indoor temperature because they don’t conduct heat like aluminium. That means the frame surface is warmer on cold mornings and less likely to attract condensation compared to standard aluminium frames.
Are thermally broken aluminium windows as good as timber for insulation?
Thermally broken aluminium is a big improvement over standard aluminium and can perform well when paired with good double glazing. However, timber still has better natural insulation and usually outperforms aluminium in frame-only comparisons.
Which window type is quieter – timber or aluminium?
Both frame types rely mostly on the glass and seals for sound control, but timber’s density and natural damping often give it an edge over standard aluminium frames, especially in older homes where aluminium joinery can rattle or flex.
How much maintenance do timber windows need?
Exterior timber needs regular painting or staining to keep moisture out, just like weatherboards or barge boards. If they are properly primed, painted and kept well-sealed (especially on the top and bottom edges), modern timber windows are durable and low hassle.
How long do timber windows last compared to aluminium?
Well-made, well-painted timber windows can last many decades in New Zealand conditions. Aluminium won’t rot, but powder coating can chalk and fade, and standard aluminium can struggle with condensation and thermal performance over time.
This article is general industry guidance. Performance outcomes depend on glazing type, installation quality, building design and maintenance. Refer to your building consent documents and builder for project-specific requirements.