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Blackout Curtains · How-to guide

How to Choose a Blackout Curtain: A Decision Framework

A step-by-step framework for choosing a blackout curtain based on how dark the room needs to be, window size, budget, and whether appearance matters as much as function.

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What matters

Key decision factors

Step-by-Step Guide

Be specific about the use case. Daytime sleeping for shift workers, a room facing intense direct sun, or a light-sensitive sleeper all call for a laminated backing (Thermaback or similar) that blocks 98% or more of light.

Step 1: How Dark Does the Room Need to Be

This is the single most important decision. A laminated backing (branded as Thermaback by Eclipse, and similarly by other premium lines) blocks 98% or more of light and is worth the premium for shift workers, light-sensitive sleepers, or rooms facing intense direct sun.

Step 2: Measure the Window Correctly

Total curtain width when closed should be at least 2 to 2.5 times the window's actual width, to ensure full overlap with no gap at the sides. This is the most common reason a "blackout" curtain still lets in light.

Step 3: Pair or Single Panels

A matched pair simplifies the purchase and guarantees consistent color and fabric between both sides of the window. Single panels still make sense for a narrow window needing only one panel, or when a specific single-panel line, like Eclipse's laminated options, outperforms the available pairs at a similar price.

Step 4: Pick the Darkest Practical Color

Darker colors block meaningfully more light than lighter ones in the same product line. Reserve lighter colors for rooms where full-dark performance is a secondary priority behind the room's overall decor.

Step 5: Match the Length to the Room

Measure from the intended rod height to the desired ending point (floor, sill, or a few inches above the floor) before assuming a standard 84-inch length fits. Most brands sell 63, 84, 95, and 108 inch options specifically because ceiling heights and rod placement vary.

Step 1: How Dark Does the Room Need to Be

This is the single most important decision.

A laminated backing (branded as Thermaback by Eclipse, and similarly by other premium lines) blocks 98% or more of light and is worth the premium for shift workers, light-sensitive sleepers, or rooms facing intense direct sun.

A woven-only fabric without a laminated backing typically blocks 90% to 95%, which is a meaningful darkening for general bedroom use, nurseries used during the day, or rooms with moderate rather than intense sun exposure.

Step 2: Measure the Window Correctly

Total curtain width when closed should be at least 2 to 2.5 times the window's actual width, to ensure full overlap with no gap at the sides.

This is the most common reason a "blackout" curtain still lets in light.

Undersized panels, not weak fabric, are usually the real problem.

Step 3: Pair or Single Panels

A matched pair simplifies the purchase and guarantees consistent color and fabric between both sides of the window.

Single panels still make sense for a narrow window needing only one panel, or when a specific single-panel line, like Eclipse's laminated options, outperforms the available pairs at a similar price.

Step 4: Pick the Darkest Practical Color

Darker colors block meaningfully more light than lighter ones in the same product line.

Reserve lighter colors for rooms where full-dark performance is a secondary priority behind the room's overall decor.

Step 5: Match the Length to the Room

Measure from the intended rod height to the desired ending point (floor, sill, or a few inches above the floor) before assuming a standard 84-inch length fits.

Most brands sell 63, 84, 95, and 108 inch options specifically because ceiling heights and rod placement vary.

See Also

Blackout Curtains Buying Guide Best Blackout Curtains for Shift Workers Blackout Curtain Not Fully Blocking Light

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Answers

Frequently asked questions

What's the single most important factor in choosing a blackout curtain?

How completely dark the room actually needs to be. A shift worker sleeping through peak daylight or a room facing intense direct sun needs a laminated backing (Thermaback or similar) that blocks 98%+ of light. A room that just needs a general dimming for better sleep, or a nursery that also functions as a daytime playroom, can do well with a woven fabric blocking 90% to 95%, often at a lower price.

Should I buy single panels or a matched pair?

A matched pair, when available at a reasonable price, is simpler and ensures consistent color and fabric across the whole window. Single panels are still a reasonable choice when only one panel is needed for a narrow window, or when a specific single-panel line offers better light-blocking performance than the pair-based alternatives at a similar price.

How much should I expect to spend on a genuinely effective blackout curtain?

The main tradeoffs as price increases are the finish (sateen versus matte), whether it ships as a matched pair, and consistency of blocking rate across colors, more than a simple better-or-worse performance gap.

Does the color of the curtain matter for performance, not just looks?

Darker colors consistently block a higher percentage of light than lighter colors at the same fabric construction, typically by 3 to 10 percentage points depending on the brand and backing type. For a room where maximum darkness matters most, choose the darkest available color in a given product line.

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