Quick Answer: GlacioTex is a phase-change material (PCM) fabric that actively absorbs and releases heat to regulate surface temperature, while TENCEL (Lyocell) is a cellulose fibre that wicks moisture and feels cool to the touch. GlacioTex provides more immediate cooling sensation. TENCEL provides more consistent moisture management. Both outperform standard polyester covers for hot sleepers.
In This Guide
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Mattress covers have become a battlefield of cooling technology claims. Two fabrics that come up repeatedly in Canadian mattress shopping are GlacioTex and TENCEL. Both promise cooler sleep, but they work through completely different mechanisms. Understanding those differences helps you pick the right mattress or protector, rather than relying on marketing language.
At Mattress Miracle, we carry mattresses with both types of cover technology. We have heard the feedback from customers sleeping on each, and the results are more nuanced than "which one is cooler."
What Is GlacioTex?
GlacioTex is a phase-change material (PCM) fabric used in some mattress covers and toppers. PCM technology works by absorbing excess body heat when you are warm and releasing it back when you cool down. Think of it as a thermal buffer.
The "phase change" refers to microcapsules embedded in the fabric that shift between solid and liquid states as temperature changes. When your body heats the fabric, the capsules absorb energy as they melt (you feel cooling). When the surface cools, they solidify and release that stored heat (maintaining a comfortable temperature).
How Phase-Change Materials Work
PCM technology was originally developed for NASA spacesuits to manage temperature extremes. The microcapsules have a specific melting point, usually calibrated to 31-33 degrees Celsius for bedding applications. When the fabric surface exceeds this temperature, the capsules absorb heat energy without increasing in temperature themselves. This creates a noticeable cooling sensation for the first 20-40 minutes of contact, after which the PCM reaches its absorption capacity and the effect diminishes until the surface cools again.
GlacioTex Strengths
- Immediate cool-to-touch sensation when you first lie down
- Active thermal regulation, not just passive moisture wicking
- Works even in a dry environment (no moisture needed)
- Effective for the initial sleep onset period when body temperature needs to drop
GlacioTex Limitations
- Cooling effect has a capacity limit. After 20-40 minutes of continuous contact, the PCM capsules are "full" and the effect diminishes until airflow cools the surface.
- Does not wick moisture. If you sweat, the sweat sits on the surface.
- PCM effectiveness can decrease over many wash cycles as microcapsules break down.
What Is TENCEL?
TENCEL is the brand name for Lyocell fibre made by the Austrian company Lenzing AG. It is produced from sustainably harvested eucalyptus wood pulp through a closed-loop solvent spinning process that recycles 99% of the chemicals used.
TENCEL cools through moisture management rather than thermal absorption. The fibre has a nanofibrillar structure with tiny channels that absorb moisture vapour and transport it away from the skin surface. This evaporative process produces a cooling effect that is gentler but more sustained than PCM.
TENCEL Strengths
- Excellent moisture wicking, absorbs 50% more moisture than cotton
- Cooling effect lasts all night because it is driven by moisture management, not a finite thermal reservoir
- Naturally smooth surface, reduces friction against skin
- Hypoallergenic and resistant to bacterial growth due to moisture transport
- Sustainable production process
- Gets softer with washing rather than breaking down
TENCEL Limitations
- Cooling is passive (moisture-dependent). If you do not generate moisture, the cooling effect is subtle.
- The initial touch is cool but not dramatically cold like PCM fabrics.
- In very dry winter conditions (common in Ontario with forced-air heating), the moisture-wicking advantage is reduced because there is less moisture to manage.
Head-to-Head Comparison
GlacioTex vs TENCEL: Side by Side
- Cooling mechanism: GlacioTex uses phase-change absorption. TENCEL uses moisture wicking and evaporation.
- Initial cool touch: GlacioTex is noticeably cooler on first contact. TENCEL is subtly cool.
- Sustained cooling: TENCEL maintains consistent temperature management all night. GlacioTex cycling depends on airflow to recharge the PCM.
- Moisture handling: TENCEL is superior. GlacioTex does not wick moisture.
- Durability: TENCEL fibres improve with washing. GlacioTex PCM microcapsules degrade over time.
- Environmental impact: TENCEL production is certified sustainable with closed-loop processing. GlacioTex uses synthetic microcapsules.
- Feel: GlacioTex feels smooth and slightly slick. TENCEL feels soft, almost silky.
- Best for: GlacioTex is best for people who run hot at sleep onset. TENCEL is best for people who sweat during the night.
Dorothy's Observation
"The customers who love GlacioTex are usually the ones who say the hardest part is falling asleep because they feel too warm," Dorothy notes. "The customers who prefer TENCEL are the ones who fall asleep fine but wake up damp at 3 a.m. Different problems, different solutions."
Which One Is Right for You?
Choose GlacioTex If:
- You feel overheated when you first get into bed
- You sleep in air-conditioned rooms (the PCM recharges faster with cooler ambient air)
- You do not sweat heavily but still feel warm
- You want a dramatic "cool pillow side" feeling from your entire mattress
Choose TENCEL If:
- You experience night sweats (from menopause, medication, or other causes)
- You want all-night temperature management, not just sleep onset cooling
- You prefer natural and sustainable materials
- You wash your bedding frequently (TENCEL holds up better to repeated washing)
- You share a bed with a partner who also runs warm
Cooling Beyond the Cover
The cover fabric is only one layer of the cooling equation. What is underneath matters just as much.
A GlacioTex or TENCEL cover on top of dense memory foam will still sleep warm because the foam traps heat below the surface. The cover can only manage the temperature at the skin-fabric interface. For whole-mattress cooling, you also need:
- Breathable foam layers: Open-cell foams or latex allow air to circulate within the mattress.
- Coil support cores: Pocket coil systems create natural airflow channels that dense foam bases do not.
- Breathable protectors: A waterproof protector with a sealed membrane can trap heat regardless of what the mattress cover does. Look for protectors with breathable TPU backing.
Our cooling mattress guide covers the full picture, including room temperature, sheets, and adjustable base airflow.
Test Both Technologies in Brantford
Mattress Miracle carries mattresses with both GlacioTex and TENCEL cover options. The best way to decide is to feel the difference yourself. Lie on each for five minutes. Notice the initial temperature, then notice how it evolves. That hands-on comparison tells you more than any specification sheet. Visit us at 441 1/2 West Street or call (519) 770-0001.
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Cooling picks we carry at Mattress Miracle:
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Find Your Perfect Mattress at Mattress Miracle
We are a family-owned mattress store in Brantford, helping our community sleep better since 1997. Come try mattresses in person and get honest, no-pressure advice.
441 1/2 West Street, Brantford, Ontario
Call 519-770-0001Frequently Asked Questions
Is GlacioTex better than TENCEL for cooling?
It depends on your type of heat issue. GlacioTex provides more immediate surface cooling through phase-change technology. TENCEL provides better overnight moisture management. If you overheat at sleep onset, GlacioTex may feel more effective. If you sweat during the night, TENCEL handles moisture better.
Does TENCEL actually keep you cool or just feel cool?
TENCEL provides real cooling through moisture evaporation, which is an endothermic process that genuinely lowers temperature at the skin surface. It also manages humidity in the microclimate between your body and the mattress, which reduces the damp, clammy feeling that makes you feel warmer than you are.
How long does GlacioTex cooling last?
The initial phase-change cooling effect lasts 20-40 minutes of continuous body contact. After that, the PCM microcapsules reach their absorption capacity and the effect diminishes until airflow cools the surface and the capsules re-solidify. Tossing and turning actually helps recharge the effect because it exposes the fabric to cooler air.
Can I wash a GlacioTex mattress cover?
Most GlacioTex covers are machine washable on a gentle cycle with cold water. However, the PCM microcapsules degrade gradually with washing and heat. Avoid hot water and tumble drying. TENCEL covers, by contrast, tend to get softer and maintain their performance with repeated washing.
Can I feel the difference between GlacioTex and TENCEL at Mattress Miracle?
Yes. We encourage customers to lie on mattresses with both cover types and compare. The initial feel is noticeably different. GlacioTex has a cooler, slightly slick first touch. TENCEL feels soft and subtly cool. Five minutes on each gives you a clear sense of which suits your preferences.
Sources
- Okamoto-Mizuno, K., & Mizuno, K. (2012). Effects of thermal environment on sleep and circadian rhythm. Journal of Physiological Anthropology, 31(1), 14. doi.org/10.1186/1880-6805-31-14
- Shin, M., et al. (2016). The effects of fabric for sleepwear and bedding on sleep at ambient temperatures of 17C and 22C. Nature and Science of Sleep, 8, 121-131. doi.org/10.2147/NSS.S100271
- Krauchi, K. (2007). The thermophysiological cascade leading to sleep initiation. Sleep Medicine Reviews, 11(6), 439-451. doi.org/10.1016/j.smrv.2007.07.001
- Mondal, S. (2008). Phase change materials for smart textiles: an overview. Applied Thermal Engineering, 28(11-12), 1536-1550. doi.org/10.1016/j.applthermaleng.2007.08.009
- Lenzing AG. (2023). TENCEL Lyocell fibre sustainability report. tencel.com
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Mattress Miracle , 441½ West Street, Brantford, ON · (519) 770-0001
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