Head-to-head · Best Cooling Pillows

Cozy Earth Mulberry Silk Pillow vs Slumber Cloud UltraCool Pillow

Which is the better buy? Side-by-side on rating, price, strengths, and watch-outs — with the published ratings we averaged to get there.

The short answer

Cozy Earth Mulberry Silk Pillow and Slumber Cloud UltraCool Pillow score essentially the same (4.5 vs 4.5). Pick the one whose trade-offs match your priorities — the strengths and watch-outs below are where they actually differ.

Ranked #5 in Best Cooling Pillows

Cozy Earth Mulberry Silk Pillow

4.5

$330

The Cozy Earth Silk Pillow is the luxury, naturally-cooling option in this lineup — 100% mulberry silk fill inside a premium bamboo viscose shell, with a 10-year warranty Cozy Earth backs against any defect. Cooling here is passive and gentle rather than aggressive, but reviewers consistently rate it the most comfortable pillow they've ever tested. Best for hot sleepers who prefer luxury bedding feel over engineered cooling tech.

Strengths

— 100% long-strand mulberry silk fill — naturally breathable, hypoallergenic, and moisture-wicking
— Premium bamboo viscose shell stays cool to the touch and doesn't trap body heat
— Plush, weightless feel comparable to a down pillow without the allergens

Watch-outs

— Most expensive pillow on this list — $330 MSRP, often discounted to $200-264 on sale
— Cooling is passive rather than active; cool-touch sensation fades under a thick cotton pillowcase
— Cannot be machine-washed — silk fill is spot-clean and air-dry only

$330 · Buy at cozyearth.com Full review →

Ranked #2 in Best Cooling Pillows

Slumber Cloud UltraCool Pillow

4.5

$154

Slumber Cloud built their reputation on Outlast PCM bedding, and the UltraCool Pillow is the flagship application of the same NASA-engineered fabric in their pillow line. CNN Underscored's tester said it was one of only two cooling pillows that actually cooled them overnight; Good Housekeeping named it Best Cooling Pillow. Pick it if you want pure cooling tech and don't need adjustability.

Strengths

— NASA-derived Outlast phase-change material absorbs, stores, and releases heat across the full night
— Named Best Cooling Pillow by Good Housekeeping and CNN Underscored for sustained overnight cooling
— Two firmness options (Soft/Medium, Medium/Firm) and three sizes including a 48-inch body pillow

Watch-outs

— Initial cool-touch sensation fades faster than some competitors as the PCM saturates
— 30-night trial is the shortest in this lineup — Saatva and Coop both run far longer
— Cooling works best without a cover; adding a thick pillowcase noticeably reduces the effect

$154 · Buy at slumbercloud.com Full review →

How they stack up

Cozy Earth Mulberry Silk Pillow

The luxury counterpoint to everything else in this lineup. Where the Coop Cool+, Slumber Cloud UltraCool, and Purple Harmony are engineering-led approaches to cooling, the Cozy Earth is a materials-led approach — silk and bamboo just happen to be naturally cool. Doesn't compete with the Saatva Latex Pillow on warranty (Saatva's lifetime beats Cozy Earth's 10 years) but does compete on feel — both pillows aim for a plush, premium hand. Skip if you want pure cooling performance; pick if you want cooling alongside a luxury sleep experience.

Slumber Cloud UltraCool Pillow

Trades adjustability for pure cooling performance versus the Coop Cool+ — UltraCool's loft is fixed at the factory but the Outlast PCM is the most proven temperature-regulating fabric in the category. Cools more aggressively on contact than the Saatva Latex Pillow, but the Saatva's all-night airflow story is more consistent in a hot bedroom. Roughly tied with the Purple Harmony on overnight temperature; the Purple offers more responsive support, the UltraCool offers a softer, down-alternative-like feel.

Specs side-by-side

Spec	Cozy Earth Mulberry Silk Pillow	Slumber Cloud UltraCool Pillow
Material	100% long-strand mulberry silk + bamboo viscose	Down-alternative polyester fiberfill
Fill	100% AAA-grade mulberry silk floss	100% polyester fiberfill (adjustable on Adjustable model)
Cover	100% premium bamboo viscose shell	100% polyester knit with Outlast coating
Cooling Tech	Passive — silk breathability + bamboo cool-touch	Outlast phase-change material (NASA-derived)
Sizes	Standard, King	Standard 20x26, King 20x36, Body 20x48
Trial Period	100 nights	30 nights
Warranty	10 years	180 days
Care	Spot clean, air dry only	Machine wash cold, tumble dry low
Loft Adjustable	No — single fixed loft	Yes on Adjustable model; fixed on standard
Certifications	OEKO-TEX certified	OEKO-TEX STANDARD 100
Loft Options	Single loft, ~5-6 inch	—

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