Fun fact: You do not need a box spring with a hybrid mattress. This is a recurring question I see, and pocketed coils in hybrids eliminate the need for one. Box springs were designed to give more support and elevate performance to traditional coil beds, which would align certain sections of coils to yield more support. Nowadays, you may actually void your warranty if you use a box spring with a hybrid mattress—be sure to check that fine print.

Innerspring

This is more of a history lesson than a type of mattress you want to shop for (unless you really love this kind of mattress; to each their own). “Traditional” innerspring mattresses are the firm-feeling beds you probably have early memories of, given that the makeup is just innerspring coils wrapped in a cover. It’s just as squeaky as you probably remember, too, as the coil type used involves connecting every coil to work as one unit.

These are Bonnell coils, and they connect both laterally and vertically. All to say, when you lie down and your weight is pressed into the mattress, all those coils act as “one for all and all for one” and simultaneously compress down. It’s not going to work wonders for pressure relief like modern hybrids will, but it is highly responsive, which means it’ll pop back into its original shape as you move around. So if you’re a sleeper who moves around between sleeping positions, coils are a good feature to have, so you’re getting near-instantaneous support.

Why aren’t traditional coils in the works with mattresses nowadays? According to Merwin, upgraded pocketed coils far outperform traditional ones. “Unlike traditional coils that are wired together and move as a unit, pocketed coils are encased individually, which allows each coil to respond independently to movement and pressure,” he said. “This design minimizes motion transfer, so when one person moves or gets out of bed, their partner feels far less disruption. It also provides more targeted support, contouring to the body in a way that improves spinal alignment and overall comfort.” While you can still find innerspring mattresses with traditional coils out there, they’re typically getting phased out in favor of hybrids. Truth be told, I’ve only tested less than a handful of them over the years. If you’re dead set on this mattress type, all power to you, and have fun on your personal mattress treasure hunt.

Memory Foam

We actually have NASA to thank for this one. If you google images of those early space missions, it’s no wonder that something was needed to keep astronauts from being jostled around inside rockets; hence, memory foam was born. It’s evolved quite a bit from those initial iterations, especially when Tempur-Pedic came onto the scene in the ’80s with a vision for it to become the basis of sleep products. Today, memory foam stands in a league of its own when it comes to the unique, compressive feel.

Memory foam is more of an umbrella term for all the iterations mattress brands have come up with today, but let’s refer to the mattress manufacturing expert for this one.

“Memory foam is produced by combining liquid polyurethane with various chemicals, like polyols and isocyanates, to enhance its viscosity and density,” says Merwin. Without whipping out the periodic table of elements and giving you a science lesson in the chemical components of this material, here’s the need-to-know: These compounds form a malleable foam that holds teeny-tiny bubbles within it. How it works is, as you lie on it, your body imparts heat onto the surface, flowing into these air pockets, which in turn allows it to become softer to contour around your body.

But for the science enthusiasts reading this, Merwin’s got you covered: “The key ingredient is a polymer that creates an open-cell structure, which allows the material to respond to heat and pressure. This is what gives memory foam its signature contouring or ‘hugging’ feel. During the manufacturing process, the liquid foam mixture is poured onto a moving line, where it expands and solidifies into large foam blocks, which we call ‘buns.’ At a high level, it’s a blend of chemistry and precision that transforms raw materials into a high-quality product.”

To say it’s a natural fit for those who need pressure relief from their mattress may be a bit too on the nose, but it’s arguably the most standout feature of this material. It also lessens the feeling of movement for the most restless of sleepers, which also makes it an attractive option for couples. Arguably, the biggest issue that plagues memory foam is heat retention, since once the heat has entered into these air chambers, it turns into something akin to microscopic saunas that can make the overall mattress into a nightmare for those who sleep warm. This is where the various iterations of foam come into play, as some brands infuse elements like graphite, copper, gel, or more advanced cooling technology like phase-change materials into the foams that they use.

Latex

The same stuff that goes into tires, balloons, and sports equipment can also be used for mattresses—and it’s the good stuff, too. Latex acts similarly to memory foam when it comes to pressure relief, but is far more reactive to you moving around. Think of a rubber band snapping back into shape when released; it’s pretty dang close to that. Many brands rely on organic rubber sap to create latex as we know it, and there are two categories of latex foam you’ll usually find with mattresses: Dunlop and Talalay. These names refer to the production process and resulting product, as liquid rubber is poured into molds, torched at high temperatures (called “vulcanization” and yes, I have to resist doing Spock’s “live long and prosper” hand signal every time), and flash-frozen to retain the feel. Dunlop is a firmer latex foam, and hence, firmer feel. Talalay yields a more plush feel. Latex is generally pretty even-keeled when it comes to temperature, too, keeping heat from accumulating within your mattress to maintain a nice, room-temperature feel.

WIRED reviewer Scott Gilbertson has applauded the organic latex construction of the Birch Luxe Natural, citing great support for the lower back region and good temperature regulation.

Birch

Luxe Natural Mattress

Smart Beds

Smart mattresses offer the ability to adjust their firmness level with the press of a button. They do this via internal air chambers or sensors that adjust coil firmness. To make your bed softer or firmer, you use a remote control or the brand’s accompanying app.

That’s not the only thing that sets this mattress type apart. Some are also outfitted with tech features such as sleep trackers and auto-adjusting pressure relief layers, as in the case of the Sleep Number p6 smart bed. Smart beds are becoming more refined as sleep tech evolves.