Memory foam

Memory foam can be found in football helmets, medical equipment, car seats, and bulletproof vests. Since the 1990s, most motorcycle seats have been made from the stuff. It’s also used in race cars that are equipped with shock-absorbent foam to help drivers walk away from crashes. NASA uses it as the base for an obstacle course that helps returning astronauts re-acclimate to Earth’s gravity. Oh, and memory foam mattresses—maybe you’ve heard of those?

Let’s sink in!

175: Estimated number of bed-in-a-box companies in the US as of late 2019

365 days: Length of the trial period offered by the mattress company Nectar

$1,095: List price of a queen-size Casper original mattress

8-10 years: Typical lifetime of memory foam mattresses

5.69%: Projected rate of growth in the global memory foam mattress market from 2020 to 2027

>7 million: Mattresses that are thrown away in the UK each year

>18 million: Mattresses that are thrown away in the US each year

5: Minutes it takes for the chemical reaction that creates a memory-foam mattress

Memory foam is viscoelastic, meaning it has both viscosity (it changes shape) and elasticity (it returns to its original form). Basically, any material that deforms slowly when pressure is applied, and then recovers and goes back to its shape after the pressure is removed—like your body on a mattress—is viscoelastic.

Memory foam comes in a variety of densities and formulas, depending on what kind of application it will be used for, but it’s all flexible polyurethane foam, made from diisocyanates and polyols. When mixed together, the reaction creates a foam in which air bubbles are trapped. Once cured, the material is used as a shock absorber in helmets and car seats, and to support our bodies in furniture, mattresses, and hospital beds. Not all viscoelastic materials are made in a lab or factory, though. Your body tissue, for example, is viscoelastic—poke a finger into your leg or stomach and you’ll see it takes a moment for your skin to go back to its original shape. Wood and concrete are also viscoelastic, and it’s a crucial property for fluid seals and gaskets.

When Fagerdala World Foams started selling the Tempur-Pedic Swedish Mattress in 1991, it was the first memory foam mattress of its kind. For about two decades, Tempur-Pedic dominated what was a niche market for high-end memory foam mattresses. Then Casper launched in 2014, promising a streamlined solution to the chore of mattress shopping, with free, supposedly no-hassle returns. Now the bed-in-a-box industry is booming. According to Michael Magnuson, founder of mattress review site GoodBed.com, the memory foam mattress market topped out with about 200 different companies offering to deliver a brand new mattress to your door. In late 2019, he estimated that there were about 175 bed-in-box-companies still operating in the US.

The US market for memory foam mattresses and pillows is projected to reach $8 billion by 2023. Those startups have threatened the mattress store sales model, and have replaced the traditional innerspring mattress, in which steel coils give the bed structure and bounce, in many bedrooms. Serta Simmons Bedding, itself a 2009 merger between two mattress companies that date back to 1931 and 1870, merged with Tuft & Needle in 2018, while Casper announced its move to open 200 brick and mortar stores in the US in early 2020, prior to going public in early February. Casper’s lackluster IPO, though, has called into question whether the mattress market is oversaturated, and whether the Instagram-ready, direct-to-consumer model for everything from sheets to leggings to shampoo is sustainable.

Some consumers have raised concerns about off-gassing from memory foam used in furniture and bedding. Diisocyanates and polyols, the main ingredients in polyurethane foam, are usually petroleum-based, though they are sometimes derived from plant oils. Memory foam does release chemicals called volatile organic compounds (VOCs), though the amount of actual exposure to chemical compounds in the foam is very low, and the smell generally goes away after airing a mattress out in a well-ventilated room for a few days. Flame-retardant chemicals and materials used to make mattresses and other furniture safer may also add to off-gassing.

From a broader perspective, hundreds of thousands of mattresses and other large pieces of furniture go into landfills every week, rarely being recycled properly, though this is not a problem specific to items made from memory foam. Businesses have taken note and are coming up with new, sustainable ways to make mattresses, which may have a side benefit of being even comfier than memory foam. One company, Cortec, is making a bed out of steel, polypropylene and polyester that can be easily separated and recycled.

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Some companies that produce memory foam for use in bedding are experimenting with infusing it with CBD oil.

Purchase a memory foam mattress online and it will arrive in a vacuum-sealed package, compressed to what seems like an impossibly small size. Most take a full day, or even two, to fully regain their original form—that’s the elasticity at work as the tiny air pockets throughout the foam essentially inflate. One of the drawbacks of memory foam mattresses is that they are heavy, and very awkward to move, but what puffs up can also be deflated back down. In this video, a couple deflates and bundles their king-size memory foam mattress using just a mattress bag, packing tape, and a shop vac.

When Alex Schwartz moved out of his dorm and into his first apartment, he found himself spending more than he could afford on furniture and other home essentials. So he devised a plan to sleep, in luxury, for free. He decided to take advantage of the fact that most bed-in-a-box startups guarantee customers that they can sleep on their new bed for an extended period of time—often 100 nights or more—and then return the mattress for any reason for a refund. At the end he writes, “I had slept on genuinely nice mattresses for 365 days—for free. Sure, changing beds every three months wasn’t the easiest thing in the world, and it required upward of $700 of disposable income to pay for them in the first place. But in addition to being (mostly) well-rested, I felt like a new inductee into a society of skilled scammers.”

He’s not the only one who figured out the mattress trick—a Wall Street Journal article profiled serial mattress returners, interviewing one scammer who kept a spreadsheet to help him stay on top of when to send his latest bed back. In 2016, the New York Times found that many “returned” mattresses were not actually returned, or even donated, but were actually hauled away and junked or recycled.

There are so many bed-in-a-box companies to choose from that a cottage industry in reviewing mattresses has sprung up, with dozens of sites dedicated to comparing the quality of sleep achieved on each brand. Reporter David Zax stumbled on a twisted web of affiliate links, paid reviews, lawsuits, and mattress business intrigue in a strangely riveting tale that all started when he scored a free mattress from a friend of a friend.