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Double Glazing for Sash Windows

Traditional sash windows are a beautiful feature in many New Zealand homes—but their single-glazed glass often lacks insulation and noise control. Magnetite for sash windows allows you to preserve the charm of your original windows while dramatically improving comfort, energy efficiency, and noise reduction.

At Magnetite, we specialise in retrofit double glazing for sash windows, providing proven solutions that reduce noise and enhance thermal insulation by up to 70%. We carefully assess your existing sash windows, custom design a solution, and install it with minimal disruption—without replacing your original window frames.

With over 25 years of experience, Magnetite has helped homeowners throughout New Zealand upgrade their sash windows through a network of trusted, licensed fabricators, estimators, and installers—primarily across the North Island.

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The Benefits of Double Glazing for Sash Windows

Magnetite retrofit double glazing to sash windows has a range of advantages. It reduces external noise, helps regulate indoor temperature, and lowers your energy bills by improving your home’s overall efficiency.

Magnetite’s award-winning retrofit system delivers all the benefits of double glazing—quieter, warmer, and more efficient living—without the need to replace your windows. It’s a cost-effective, sustainable alternative that avoids mess, waste, and the loss of your home’s original features.

Noice ReductionNoice Reduction

Proven Results



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Our window systems have been independently tested by the National Acoustic Laboratories in line with National Fenestration Rating Council (NFRC) regulations. Reduce up to 70% of noise through windows or doors with Magnetite secondary glazing solution.


View Noise Reduction Technical Data
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Our window systems have been independently tested by the Window Energy Rating Scheme (WERS) in line with National Fenestration Rating Council (NFRC) regulations. Improve up to 70% of thermal efficiency of your windows or doors with Magnetite secondary glazing solution.


View Thermal Improvement Technical Data


Why homeowners choose Magnetite

Acoustic & thermal insulation

Our secondary glazing solution is tailored to your needs, providing effective soundproofing and year-round thermal comfort. Our systems—ideal for double glazing for sash windows—are independently tested and proven to reduce noise and improve thermal performance by up to 70%.


Minimal impact to exterior of the homes

Whether it’s a heritage home, apartment, or strata property, Magnetite delivers excellent acoustic and thermal insulation without changing the appearance of your original windows—making it perfect for sash window double glazing.


Increase property value

Installing double glazing for sash windows increases your home’s value by improving comfort, boosting energy efficiency, and reducing long-term running costs.


Sustainable Living

Double glazing your existing sash windows helps stabilise indoor temperatures without over-relying on heating or cooling. Lower energy use means fewer greenhouse gas emissions. Our retrofit solution also reduces waste by preserving existing window frames instead of replacing them.


Custom installation

Magnetite’s retrofit double glazing is designed to suit a wide range of window styles, including sash windows, timber windows, sliding, casement, and multi-panel designs—ensuring a seamless fit and long-lasting performance.

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