How Magnetite Window Inserts Work

Upgrade Your Existing Windows Without Replacing Them

Magnetite adds a custom-made interior window insert to your existing window, creating a secondary glazing system without removing the original frame or glass.

Three elements work together: an additional clear panel, an insulating air space and a continuous magnetic seal. Together, they reduce pathways for outside noise, air leakage and heat transfer while keeping your existing windows in place.

Magnetite Canada

Magnetite® was developed by Kenneth J. Foster, an energy physicist, in conjunction with the M.I.T. Innovation Center in 1978. He was eventually granted U.S. Patent No. 4473980. Mr. Foster combined the concepts of using an acrylic window, like they use on jet airplanes, and a magnetic seal, which is how your refrigerator door stays both closed and air-tight, to create the most energy-efficient window on the market.

More than 37 years later, Magnetite® is still the best alternative!

Stop outside noise, eliminate condensation and save energy without replacing your windows!

The Three Parts That Make Magnetite Work

1. The Interior Window Insert

A custom-built clear panel adds another physical barrier between the room and the outdoor environment. Each insert is measured for the individual opening so it fits the existing window rather than requiring the original unit to be removed.

2. The Insulating Air Space

The space between the original glass and the Magnetite insert separates the two glazing surfaces. This air cavity acts as a thermal and acoustic buffer, reducing the direct transfer of heat and sound through the window assembly.

3. The Magnetic Perimeter Seal

Sound and drafts can pass through surprisingly small gaps. Magnetite uses a continuous magnetic mounting system around the insert to create a tight perimeter seal and limit these leakage paths.

What Changes After Magnetite Is Installed?

Outside Noise Has More Barriers to Cross

Sound reaches a room through vibration and air leakage around the window. Adding another glazing layer, separating it from the existing glass and sealing the perimeter creates additional barriers that reduce sound transmission.

Magnetite reports outside-noise reductions of up to 70%, with final performance depending on the existing window, air space, insert configuration and installation. Published Magnetite acoustic results include ratings of up to STC 43 for single-pane wood windows and up to STC 46 for double-pane aluminum windows.

Drafts and Air Leakage Are Reduced

Older windows can allow air to move through worn seals and gaps around the opening. The interior Magnetite system adds another sealed layer, reducing unwanted air movement and cold drafts.

Heat Transfer Through the Window Is Reduced

The additional glazing layer and insulating air space slow heat movement through the window assembly. During colder weather, this supports better heat retention. During warmer weather, the additional barrier can reduce unwanted heat transfer into the room.

Magnetite reports savings of up to 30% on heating and cooling energy bills, although actual savings depend on the building, existing windows, climate and energy use.

Condensation Risk Can Be Reduced

Condensation develops when warm, moisture-filled indoor air reaches a sufficiently cold surface. By improving thermal performance and helping maintain a warmer interior-facing surface, Magnetite can reduce surface condensation in suitable conditions.

Indoor humidity, ventilation and the condition of the original window also affect condensation, so no window insert should be presented as a guaranteed cure for every moisture problem.

Is Magnetite the Same as Standard Double Glazing?

Both systems use multiple glazing layers and an air space to improve window performance, but they are built differently.

Magnetite is therefore better described as retrofit secondary glazing rather than a conventional replacement double-glazed window.

If the existing frame is severely damaged, rotten or structurally failing, repairing or replacing the original window may be the more appropriate first step.

From Your Existing Window to a Custom Magnetite System

Step 1 — Assess

The existing window, frame and opening are reviewed along with the main performance problem, such as noise, drafts, temperature changes or condensation.

Step 2 — Measure

Each opening is measured individually. This is important because small gaps can affect both sound and thermal performance.

Step 3 — Custom Build

The insert is manufactured to match the dimensions and requirements of the opening. Magnetite window inserts are manufactured in Canada.

Step 4 — Install and Fit

The completed insert is professionally fitted on the interior of the existing window and checked for correct perimeter contact and operation.

Where Does Magnetite Work Best?

Magnetite can be considered when the existing window is still structurally sound but its acoustic or thermal performance no longer meets the needs of the space.

Homes and Condos

Suitable for rooms affected by traffic, neighbours, cold drafts, temperature swings or window condensation.

Commercial Buildings

Interior installation allows offices, hotels, healthcare facilities and other occupied buildings to improve window performance with less disruption than full replacement.

Heritage and Historic Properties

Because the original exterior window can remain in place, interior secondary glazing can be useful where architectural appearance or original window fabric needs to be preserved.