What is Cardinal Glass, and what it means for your windows

Cardinal Glass is a US-based glass manufacturer that makes coated glass and sealed insulating glass units for windows and doors made by other companies. When a quote says "Cardinal glass," it tells you who made the glass package inside the frame, not who made the window.

Because the glass package does most of the work in winter, it's worth knowing what Cardinal glass windows actually include and what the terms on your quote mean. This guide explains them in plain language and shows how to find out exactly what glass you're getting.

Cardinal Glass in one paragraph

Cardinal Glass Industries is a privately held, management-owned company that makes float glass, low-emissivity (LoE) coatings, tempered and laminated glass, and finished insulating glass units. Its insulating glass division, Cardinal IG, supplies sealed units that window makers set straight into their frames.

Window manufacturers specify Cardinal for two practical reasons. First, they receive a finished, factory-sealed unit with the coating, spacer and gas fill already in place. Second, the coatings come with published performance data, which makes it easier to design a window that meets ENERGY STAR criteria. Our article on pre-sealed Cardinal glass vs in-house assembled glass covers how those units are made and why factory sealing matters.

What the glass terms on your window quote mean

Most window quotes describe the glass in a short code: the number of panes, the coating, the gas and the spacer. Here's what each term means and why it matters in a Canadian winter.

If you'd like a broader glossary, including double-glazed versus double-pane, see our guide to window glass terminology .

LoE coatings explained

A Cardinal LoE coating is a thin layer of silver and other materials applied to the glass, and each product is tuned to a different balance of heat loss and solar heat gain. The name tells you which balance you're getting.

The small raised number after "LoE" indicates the number of silver layers: Loē² has two, and LoĒ³ has three. More silver layers mean more control over the sun's heat. Treat the three-digit number as a product name rather than a measurement. These are the coatings Cardinal publishes for homes:

For scale, Cardinal's published centre-of-glass data for LoE-366 in a double-pane unit with argon shows a U-factor of about 1.37 W/m²·K and a visible light transmission of about 65%. Keep in mind that centre-of-glass numbers leave out the frame and edge, so a whole-window U-factor will always be higher. Cardinal's triple-pane units can carry coatings on two surfaces, for example LoE-366 paired with LoE-180, which is why a triple-pane quote may list two coating names. The right coating depends on how much winter sun you want to let in and how much summer heat you want to keep out. Ask which coating is specified for each window and why, especially for large south- or west-facing glass, where solar heat gain makes the biggest difference. For how coatings fit into a full window, see our page on energy-efficient windows , and for the other glass types available, see window glass options .

Spacers and why the glass edge matters

The spacer decides how cold the edge of your glass gets, and the edge is usually where condensation starts. A warm-edge spacer conducts less cold to the room-side pane than a plain aluminum one.

Cardinal launched its stainless-steel XL Edge spacer in 1993 and replaced it with Endur IG in 2014. Cardinal describes Endur as a warm-edge design that improves the unit's U-factor and its resistance to interior condensation. Cardinal seals its units with a dual-edge seal to keep gas in and moisture out. Our article on how window spacers prevent condensation and heat loss compares spacer types in more detail.

How to find out what glass is in your windows

The fastest way to find out what glass you're getting is to ask the window manufacturer for the full glass specification in writing. Cardinal itself tells homeowners to ask their window supplier whether they use Cardinal IG units.

1. Check your quote or order for the glass line: number of panes, coating name and surface, gas fill and spacer.
2. If the quote only says "low-E" or "energy-efficient glass," ask which manufacturer made the unit and which coating is used.
3. Ask whether the rating on the quote is for the whole window or only the centre of the glass.
4. For existing windows, ask the company that made them whether the units carry any identifying marks, and where to find them.

A clear answer to those four points tells you more about winter comfort than any brand name alone.

Cardinal glass in Canadian Choice Windows & Doors windows

Canadian Choice Windows & Doors builds its vinyl windows at its own facility in Canada and uses glass units sourced from Cardinal I.G. and Guardian Glass, both with LoE coatings. So while Cardinal is a US manufacturer, the window around the glass is made in Canada.

That answers what most people mean when they search for Cardinal glass Canada: the glass is imported, and the frame, assembly, and installation can still be Canadian. It's worth checking all three on any quote.

Our product pages list these glass features:

• Glass units from Cardinal I.G. and Guardian Glass with LoE coatings, on our vinyl windows and sliding and stacking patio doors .
• Argon gas fill as standard.
• The Endur IG Cardinal spacer system.
• Triple glass available as an option on several window series.

Your quote will show the exact glass package for each window, so you'll know which supplier, coating and pane count you're getting before anything is ordered. Our windows come with a 25-year transferable warranty. To see the options in person, book a free consultation .

Frequently asked questions

Is Cardinal Glass made in Canada?

No. Cardinal is a US-based manufacturer, so Cardinal glass in Canada arrives as finished glass or sealed units from Cardinal plants. The window around it can be Canadian-made: Canadian Choice Windows & Doors builds its vinyl windows at its own Canadian facility.

What does LoE-366 mean on a window quote?

It means the glass has Cardinal's LoĒ³-366 coating, a three-layer silver coating designed for strong solar control with clear visibility. Cardinal designs it for surface #2, the inside face of the outer pane. On a quote, it's often paired with argon and, in triple-pane units, with a second coating such as LoE-180.

Is Cardinal glass filled with argon?

Cardinal IG units combine LoE coatings, warm-edge spacers and argon fill. Whether your unit has argon depends on what the window maker orders, so check the glass line on your quote. Canadian Choice Windows & Doors windows use argon as standard.

Who handles a claim if a Cardinal glass unit fogs between the panes?

Start with the company that made and installed your window, because it holds the warranty for the finished product. For Canadian Choice Windows & Doors windows, you can submit a warranty claim online. Fog between the panes means the edge seal has failed, so the unit usually needs replacing.

Does Cardinal glass make windows quieter?

Not because of the brand. Noise reduction comes mainly from thicker glass and laminated glass, which Cardinal also makes. The gas fill and the LoE coating do little for sound, so ask about laminated glass if noise is your main concern.