Backing and Construction Types
Laminated backing (Thermaback and similar branded names): A foam or acrylic layer bonded to the back of the face fabric during manufacturing.
This construction consistently blocks the highest percentage of light, generally 98% to 99.9%, and also provides the most noticeable thermal insulation.
The tradeoff is a stiffer, heavier fabric.
Woven-only or triple-weave fabric: A tightly woven fabric without a separate laminated layer, sometimes described as "triple weave" or "three-pass" construction.
This typically blocks 85% to 95% of light depending on color and weave density, at a lower price and with a softer drape than laminated options.
Sizing Correctly
Total panel width when closed should be at least 2 to 2.5 times the window's width, to ensure full overlap and minimize side light gaps.
Mounting the rod 4 to 6 inches beyond the window frame on each side, rather than directly above the frame, closes more of the remaining gap than upgrading the fabric alone would.
For length, measure from the planned rod height down to the intended ending point before choosing a stock length.
Most brands offer 63, 84, 95, and 108 inch options specifically because standard lengths do not fit every ceiling height and rod placement.
Thermal and Noise Benefits
Most blackout curtains, regardless of construction type, provide some degree of thermal insulation and noise reduction alongside light blocking, since the same dense material that blocks light also dampens sound and slows heat transfer.
Brands that cite a specific percentage (commonly around 25% for both noise and energy loss) are referencing third-party lab testing rather than a purely marketing claim, and this figure is a reasonably reliable point of comparison across brands that publish it.
Colorway Tradeoffs
Darker colors block more light than lighter colors with in the same product line, typically by 3 to 10 percentage points depending on construction.
This is consistent across nearly every brand in the category.
For a room w here maximum darkness matters most, choose the darkest available color; for a room w here lighter, brighter decor matters more, expect a real tradeoff in blocking performance.
Care Instructions
Wash on a cold, gentle cycle and hang to dry rather than using a hot dryer, which is the most common cause of a laminated backing cracking or separating from the face fabric over time.
A light steam or low-heat iron is generally safe for removing packaging creases, particularly on sateen finishes that show creases more visibly than matte fabrics.
Our picks
Products we recommend
As an Amazon Associate I earn from qualifying purchases. Picks are based on manufacturer specs, independent reviews and owner reports.
Top pickEclipse
Thermaback backing is the most effective light and heat blocker in this list
- 52 x 84 inch single panel, grommet top
- Thermaback triple-weave blackout backing
- Blocks 98% to 99.9% of light
- Reduces energy loss through the window
- Machine washable
✓ Pros
- Thermaback backing is the most effective light and heat blocker in this list
- Noticeably reduces afternoon heat buildup in a west-facing room
- Available in dark colorways that maximize both light and heat blocking
✕ Cons
- Sold per panel, so a full pair costs roughly double the single-panel price
- Stiffer fabric hand-feel than a fabric-only curtain
Exclusive Home Curtains
Sheer overlay softens the look of the room during the day, useful for a nursery that doubles as a playroom
- 52 x 63 inch pair, hidden tab/rod pocket top
- Layered sheer overlay over a solid blackout lining
- Softer, more decorative look than a solid blackout panel
- Machine washable
- Available in multiple color combinations
✓ Pros
- Sheer overlay softens the look of the room during the day, useful for a nursery that doubles as a playroom
- Blackout lining still blocks most light once fully closed
- No cords, hangs from a rod pocket or hidden tabs
✕ Cons
- Layered construction blocks slightly less light than a solid single-layer blackout panel
- 63-inch length is short for taller nursery windows
Best overallEclipse
37-inch width is proportionally right for a narrow window, unlike bulkier 52-inch panels
- 37 x 84 inch single panel, rod pocket top
- Thermaback blackout backing
- Blocks over 99% of light
- Reduces noise and insulates against heat and cold
- Machine washable
✓ Pros
- 37-inch width is proportionally right for a narrow window, unlike bulkier 52-inch panels
- Blocks over 99% of light, matching the wider Eclipse Palisade panel
- Rod pocket top gives a traditional, gathered look that suits a small decorative window
✕ Cons
- Rod pocket top is slower to open and close than a grommet panel
- 84-inch length needs hemming for a shorter small window
FAQ
Common questions
What's the difference between 'blackout' and 'room darkening' curtains?
Room darkening curtains typically block 80% to 95% of light through a tightly woven fabric alone, without a dedicated blackout layer. True blackout curtains add a laminated backing, a separate lining, or a very dense triple-weave construction specifically engineered to block light, generally reaching 95% to 99.9%. The terms are sometimes used loosely in product titles, so check the specific stated blocking percentage rather than relying on the word 'blackout' alone.
Do blackout curtains actually save on energy bills?
Yes, to a measurable but modest degree. Brands commonly cite figures around 25% reduction in energy loss through a curtained window, which reflects reduced heat transfer in both summer and winter. The exact savings depend on the window's existing efficiency, the room's sun exposure, and how consistently the curtains are closed during peak heat or cold.
Can blackout curtains be tailored or hemmed to a custom length?
Yes, most blackout curtains can be hemmed by a tailor or with fusible hem tape, the same as any other curta in fabric, as long as the laminated backing is not damaged by excessive heat during the process. For a large discrepancy between the available lengths and the actual window height, hemming a longer length down is usually more reliable than trying to extend a shorter one.
How do I know if a listing's blackout percentage claim is realistic?
Look for a specific stated percentage (such as 98% to 99.9%) alongside a named backing technology (Thermaback, Thermax, or similar branded terms), rather than just the word 'blackout' with no supporting detail. Reviews mentioning the room's actual darkness at a specific time of day are also a reliable secondary signal, more so than the product photos alone.
Keep researching
Related guides & comparisons
