Phase Change Materials in Mattresses

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If you’ve ever seen a mattress company tout its “phase changing materials” for cooler sleep and better nights, you may have wondered what that actually means – and how exactly it works. Here’s what to understand about the technology behind phase change materials, and whether they really are the secret to more comfortable nights.

Bottom Line: What Are Phase Change Materials?

Phase change materials (PCMs) are materials that change states depending on their temperature. They’re sometimes used in mattress construction as a way to improve temperature regulation.

What Are Phase Change Materials?

As the name implies, phase change materials, well, change from one phase (solid, liquid, or vapor) to another based on their temperature. You’re familiar with a phase change material already: Water. Their ability to truly phase change makes them popular for a range of products, and that includes mattresses. In that specific application, phase change materials may be able to improve thermoregulation for sleepers, which translates to more comfortable sleep throughout the night.

Some mattress manufacturers are using phase change materials, either blended into their proprietary comfort materials or in performance fabrics on the mattress top, to absorb body heat and release it as the body cools. Since it’s normal for body temperature to fluctuate while we sleep, this catch-and-release function of phase change materials helps ensure temperature regulation all night. In other words, the phase change material in the mattress may help you cool down when you get hot and warm up when you start cooling down. That level of temperature regulation could mean fewer disruptions in the night.

Do Phase Change Materials Actually Work?

Anecdotal evidence says phase change materials do indeed work well in mattresses, and there is some clinical research that supports the claim as well. According to one small study, mattresses made with phase change materials may improve the body’s thermoregulation, which is how the body maintains its internal temperature. The study’s participants had lower skin temperatures after laying on a mattress with phase change material compared to a conventional mattress. However, the difference wasn’t enough to be noticeable to the participants, who didn’t report any changes in thermal comfort or thermal perception after laying on both types of mattresses.

Pros of Phase Change Materials

  • Temperature-regulating. Phase-change materials in a mattress are designed to help maintain a comfortable body temperature all night. That’s appealing if you tend to overheat at night or find yourself always reaching for an extra blanket.
  • Versatility. Phase change materials can be used in a few different ways in a mattress. You may find them blended into foams or in the fabric of a mattress cover. Either way, the idea is more comfortable sleep all night long.

Cons of Phase Change Materials

  • Limited data. There isn’t a lot of clinical research into the efficacy of phase change materials in mattresses. While anecdotal evidence does appear to support the claim that these materials can mean cooler nights, more research is needed for a definitive answer.
  • High price point. Phase change materials are considered innovative upgrades, which means you’ll generally find them on high-end mattresses–with higher price tags to match.

Other Cooling Materials

If your sleep temperature is an ongoing issue, you have options beyond phase change materials. Gel-infused memory foams use cooling infusions of gel that are designed to minimize heat retention (a common issue for memory foam). Another option are perforated foams, which have thousands of tiny holes that let body heat escape.

Latex is a great alternative if you don’t like the “hugged” sensation of memory foam. Not only does it have a more buoyant feel, with the sensation that you’re less in the mattress than on it, it’s also naturally temperature-regulating.

Hybrid mattresses also tend to offer better air circulation than all-foam options. The innerspring layer promotes airflow, which can help cool things down at night.

Frequently Asked Questions

What is phase change material in Tempur-Pedic? 

Tempur-Pedic has a proprietary phase change material it calls PureCool+. According to the company, it’s an exclusive formula with a lightweight, breathable construction to better promote airflow. The molecules react to temperature, transforming from a solid to liquid to absorb heat. It’s an upgrade to the brand’s original phase change material, PureCool, and has more cooling power per cubic foot. In fact, Tempur-Pedic says the material (which is available in its line of TEMPUR-Breeze mattresses) can help sleepers feel up to 8 degrees cooler at night.

Is there a mattress that changes temperature?

Actually, there are a few mattresses that adjust for temperature. The TEMPUR-Breeze line from Tempur-Pedic uses the company’s PureCool+ phase change material to keep sleepers cool. The Pod from Eight Sleep automatically heats or cools before bed to help you fall asleep faster, then adjusts throughout the night. The system uses circulating water to regulate temperature. The Climate360 smart bed from Sleep Number also actively cools, warms, and adjusts temperature at night.


Phase change material sounds high-tech, and in a mattress, it really is. Mattress companies are integrating phase change material into their covers or comfort layers as a way of helping sleepers stay comfortable all night. Because the material can retain and release body heat, it works to maintain body temperature, which means fewer disruptions because you suddenly realize roasting or freezing. While more research is needed to really refine the technology and validate its efficacy, many people are singing its praises. Just keep in mind that phase change materials are often found in higher-end mattresses, so you’ll be paying a premium for this upgrade.

If you’re looking for a mattress that will help you sleep cooler, you do have less expensive options. Check out hybrid mattresses with gel-infused foam or latex and see if that does the trick!

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