Triangle Window Shades: Real Cases + How to Cover an Angled Window

Triangle windows are the star of many vaulted living rooms, A-frame homes, and attic bedrooms. They flood a room with light — but they're also the hardest windows to cover. Off-the-shelf shades are all built for square and rectangular windows, so a triangle window almost always has to be custom made.

Instead of pure theory, this guide shows real triangle window shade cases we've built — each with a short explanation — so you can see exactly what a finished triangle (or angled) window treatment looks like and how to choose the right one.

Written by the EASEEASE Curtains design team — specialists in custom, made-to-fit shades for triangle, arched and other angled windows. Last updated July 2026.

What Can You Put on a Triangle Window?

Only three treatments truly fit triangular and angled windows: honeycomb (cellular) shades, custom linen curtains, and custom shutters. Of the three, honeycomb shades are the most popular and most forgiving — and they're where most of our triangle cases live. For a full walk-through of curtains and shutters on every odd shape, see our complete guide to arched & odd-shaped windows.

Real Triangle & Angled Window Shade Cases

Triangle Honeycomb Shade — Manual Cord Control

This standard triangle window has a single custom honeycomb shade that raises and lowers on a manual cord, hugging the angled edge as it opens and closes. The honeycomb air pockets give excellent light and heat insulation — blocking summer heat and holding winter warmth (the U.S. Department of Energy notes cellular shades can cut window heat loss by up to 40% and solar heat gain by up to 60%) — and it can be built as full blackout for a bedroom or light-filtering for a living room. The gaps and uneven edges people fear most on triangle windows are sealed cleanly here.

Extra-Large Triangle Window — Two Panels Joined

When a triangle window is very large, a single shade is hard to operate and won't hang evenly, so we build it as two honeycomb panels joined together — each half tracks its own angled edge. It reads as one continuous surface but works far better in practice, in manual or motorized versions.

Trapezoid Window — Top-Down Motorized

A narrow-top, wide-bottom trapezoid window works beautifully with a top-down motorized honeycomb shade, letting light in from the top while keeping privacy below.

Extra-Wide Trapezoid — Single Shade

An extra-wide trapezoid built as a single honeycomb shade, up to the 118-inch single-panel limit.

Extra-Wide Trapezoid — Three Panels Joined

For a very wide trapezoid span (beyond 118 inches), we build it as multiple panels made side by side — here, three joined honeycomb panels that operate smoothly and hang evenly.

Motorized & Smart Control

Triangle and trapezoid windows are often mounted high and out of reach, which makes manual operation a hassle. Motorized honeycomb shades solve it with a remote or phone app, and integrate with smart-home systems. Because cellular shades are forgiving on measurements, even an irregular angle sits flush — the biggest reason they're easier than shutters.

EaseEase Motorized Blinds

Triangle Honeycomb Shade Sizing & Specs

Order free honeycomb fabric samples

How to Measure a Triangle Window

1. Measure the base width at the bottom of the window.
2. Measure the length of each sloped side.
3. Measure each angle where the sides meet (a laser measure or angle finder helps).
4. Note the frame depth if you're mounting inside the recess.
5. For a span over 118 inches, decide the split points for a multi-panel build in advance.

Honeycomb shades are forgiving on tolerance, but accurate angles still matter. Not sure how to measure? Send us a photo of your triangle window and our design team will handle it.

How to Install a Triangle Window Shade

A triangle honeycomb shade mounts to the level top edge of the window, not the angled sides, so installation is simple:

1. Hold the shade up in the opening to check clearance and depth before drilling.
2. Fix the L-brackets along the top, about 3 inches in from each side (add a middle bracket on wider shades). Mark and pre-drill.
3. Check the brackets are level and shim if needed — level mounting is key to smooth operation.
4. Screw the L-brackets in through the top holes (use wall anchors on drywall).
5. Snap the shade in: insert the front of the headrail into the bracket clip, then push the back edge up until it clicks.

Motorized shades install the same way, with the motor already fitted in the headrail. Prefer not to DIY? We can arrange professional in-home installation.

Curtains & Shutters for Triangle Windows

Custom linen curtains look beautiful on a triangle window, but they can't slide open — they're tied back into a fixed shape, so they suit living-room, airy sheer looks rather than bedroom blackout. Used for bedroom blackout, the fabric bunches heavy and bulky along the angled edge (see the customer photo below). Custom shutters fit virtually any shape and offer infinitely adjustable light and a premium architectural look, but need millimeter-precise measuring, cost more, and can't reach 100% blackout. See both in detail, with photos, in our complete guide to arched & odd-shaped windows.

EaseEase Hunter Linen Blackout Curtains

Triangle Window Treatments Compared

Bottom line: for most triangle windows — especially bedrooms and high, hard-to-reach spots — honeycomb shades give the best mix of blackout, insulation, and easy motorized control.

Frequently Asked Questions

Ready to Cover Your Triangle Window?

EASEEASE Curtains = custom affordable designer shades / curtains. We design a shade for every triangle and angled window individually — with better fabric, better drape, and a premium look, backed by free design and free fabric samples.

Prefer to compare materials first? Order free fabric swatches and see the difference at home.