Does Your Bed-in-a-Box Need a Box Spring?

WIRED

2 days ago

If you haven't seen a box spring in a while, it's not your imagination—a mattress expert breaks down when you might need this dinosaur of the sleep world.
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You're probably familiar with a box spring, the simple wood frame with springs that acts as a support base under older mattresses. It's not a highly technical piece of equipment like a smart bed (or a trampoline, wouldn't that be fun)—this kind of mattress foundation has persisted through the ages solely due to its simple and durable design. But have you noticed you may not be seeing them as often nowadays?
In my opinion as a career mattress tester, contemporary mattresses are on their way to making this furniture addition obsolete. However, that doesn't mean it automatically gets booted from your mattress setup scenario. Let's unpack what a box spring actually is, why you may or may not need one, and where it could set you and your mattress up for success.
For this article, I'm relying on my own expertise as a Spencer Institute–certified sleep science coach and mattress tester of five years, as well as that of John Merwin, CEO of 3Z Brands (maker of Helix, Nolah, Bear, and Leesa) and founder of Brooklyn Bedding. The Box Spring's Backstory
Mattresses back in the day weren't what they are now, and that time frame extends from the earliest iterations of mattresses to 50 years ago to today. Support was, let's just say, pretty abysmal. Think of a bed completely filled with hay, and more often than not that's what you had to work with. The box spring was meant to alleviate that lack of support with its introduction during the late 18th century. Engraving depicting a coiled spring mattress, demonstrating its lightness compared with a feather or a feather and spring mattress of a similar size. Its manufactures also recommended it as "it does not harbour vermin or dirt". (Photo by: Universal History Archive/UIG via Getty Images) UniversalA box spring involves a wooden frame or base that contains innerspring coils or has coils set atop the base. A fabric casing is often involved to keep everything contained. This is a deliberate design choice, because the coils in the box spring are springing up to meet the mattress atop it. The wooden frame has slats to ensure that no sagging is happening around the center of the bed, while providing some foundational backup to the coils.
If we think back to the ye olde mattress days, or the time before mattresses in a box were a thing (which was 2004, to be exact), the box spring was the predominant piece of furniture that accompanied your mattress. As time went on, box springs evolved to support a specific type of mattress—traditional innerspring coils.
'Traditional coils are often referred to as Bonnell coils, which have been used in mattresses for generations,' says 3Z CEO John Merwin. 'They're designed in an hourglass shape where they're wider at the top and bottom with a thinner middle to offer a combination of support and flexibility."
But why does this coil type need a box spring in the first place? Ultimately, it came down to making sure sleepers were truly getting support across the board, er, box spring. Traditional coils 'are designed to offer a combination of support and flexibility, but because these coils are connected by a network of wires, they tend to move as a unit rather than individually," Merwin says. 'This makes them more dependent on a box spring or foundation to provide proper support and absorb shock.'
Beds with Bonnell coils are still out there, but usually not as the standout mattress material within a bed. Some hybrids may use it at the base of the mattress for durability, with pocketed coils and memory foam layered atop it. Still, in these cases, box springs aren't necessary, since the coils are doing the heavy lifting. An example of this would be the Brooklyn Bedding Signature Hybrid, which utilizes modern pocketed coils for durability and support. Box Springs and Your Mattress (in a Box)
Owners of modern-day mattresses, either from a box shipped to your house or a brick-and-mortar mattress store, need to be extra careful when pairing a box spring with their bed, if it all. Merwin says the box spring helps extend the life of the mattress by reducing wear and tear, especially since Bonnell coils don't offer the same level of motion isolation or adaptive support as more modern pocketed coil designs. 'While still found in some entry-level models,' Merwin says, "Bonnell coils have largely been phased out in favor of more advanced coil systems that better align with today's comfort and durability standards."
So, the reality is (A) you probably don't need a box spring, and (B) a box spring could actually be damaging to your bed. Not to mention, it could potentially void your warranty coverage. For memory foam mattresses or hybrids, the coil components within a box spring could actually wear down each respective material and counteract long-term durability and support. The usage of coils in a hybrid mattress actually mimics the performance of a box spring, so you don't actually need to use one. Pair a box spring with a hybrid and you've potentially got a 'too much of a good thing' situation on your hands.
But let's say that you choose to continue down the path of the box spring—some brands may offer a version compatible with your mattress of choice. You can also cross-verify with customer service to see if a box spring would make an ideal pairing with your mattress. If your bed frame lacks slats or any sort of centralized support, that's a situation in favor of box springs. In that case, you can expect to shell out anywhere from under $100 to $300 for a box spring, depending on the size of mattress you have. But as a professional mattress tester, always keep the focus on the best mattress for you first, and then the subsequent accessories after. Your search shouldn't be, 'Can I find a bed to work with my box spring?' Support System FTW
What should you be using for your mattress, then, if not a box spring? Plopping it on a bed frame with central support beams, a mattress foundation, or a smart bed base are all viable options. This is another warranty caveat—make sure that with whatever you choose, your base has the support required by your mattress's warranty coverage. This could mean the wooden slats are a certain number of inches apart, or confirmation that there's a support beam running vertically through the base to keep the center from sagging. Some models, like the Wolf Memory Foam Hybrid, actually supply a base with your purchase, so you're covered from the jump. Even better news: We're on top of testing bed frames, too.