Memory Foam vs. Innerspring – What’s the Difference?
For over a century, innerspring mattresses have been an industry standard. These beds have found their way into almost every home in the United States. However, as mattress technology has evolved, the dominance of spring mattresses has been challenged by the unique and modern features of memory foam.
Memory foam mattresses are a newer and more innovative take on mattress technology. The material contours the body, providing immense pressure relief and support—something most innerspring coils can’t do. So what are the big differences between memory foam and innersprings, anyway? In our post, we review the main things you need to know when shopping for your best mattress.
What is a Memory Foam Mattress?
Memory foam—otherwise called viscoelastic polyurethane foam—is the more modern option for bedding. These mattresses are temperature and pressure-sensitive, so they adapt to virtually all body types and offer dynamic support.
Memory foam is often the go-to choice for those with back and joint pain because of its ability to contour the body and provide pressure-point relief, which reduces aches. It’s also a great option for couples since memory foam naturally absorbs movement and prevents sleep disturbances from tossing and turning.
Some of the different types of memory foam mattresses include:
Gel Memory Foam
Gel memory foam was developed with the intent of creating a mattress with breathability and temperature regulation. The foam layers of a gel memory foam mattress are infused with cooling gels that pull body heat away from the sleeper, making for a cool night’s sleep. The way gel is infused within the foam may vary between different manufacturers, but the function is essentially the same.
For an in-depth comparison of the two types of foam, see our memory foam vs gel foam mattress guide.
Plant-Based Memory Foam
This type of memory foam contains a portion of plant-based ingredients, like soy, instead of only petroleum-based chemicals. Plant-based memory foam addresses some of the concerns regarding memory foam’s slow response time.
With a much larger cell structure, plant-based memory foam has a response time of roughly 5-8 seconds, which is a noticeable improvement from gel memory foam’s 30 second response time. The plant-based design also dissipates heat faster.
Benefits of a Memory Foam Mattress
Memory foam mattresses are perfect for back sleepers, side sleepers, and stomach sleepers alike because they’re available in all firmness levels. The responsive material adjusts to movement and evenly distributes body weight throughout the night.
These mattresses contour the body in a way that spring mattresses cannot, allowing them to provide pressure-point relief for the neck, spine, and joints. Along with that, both gel memory foam and plant-based memory foam promote breathability and coolness for sleepers.
Drawbacks of a Memory Foam Mattress
Even though many mattress companies make their memory foam beds with cooling technologies, one major drawback to sleeping on memory foam is the potential for night sweats and overheating. Standard memory foam is like a giant sponge, so it’s not a surprise that it absorbs and retains body heat.
Cooling gel beds and plant-based ingredients can improve foam breathability, but those who sleep especially hot may want to opt for a bed with a coil system for better temperature control.
In addition to heat retention, some newly-purchased memory foam mattresses may omit an off-gassing odor upon first unboxing, particularly some inexpensive memory foam mattresses under $500. This off-gassing scent doesn’t pose any actual health risks—if you’ve ever been inside of a new car or smelled a fresh coat of paint, you’ve experienced off-gassing—but the smell can be bothersome to many.
Off-gassing occurs when volatile organic compounds (VOCs) break down and release an odor. VOCs are present in both natural and synthetic materials, but it can be largely avoided by looking for memory foam mattresses with plant-based foam or a CertiPUR-US® certification since these beds have fewer VOCs.
And, if your mattress does release any off-gassing odor, we suggest letting it sit in a ventilated room for a few days before use. This will give it time to air out. If you need to sleep on it right away, a memory foam mattress protector can help contain the worst of it.
What is an Innerspring Mattress?
Before there was memory foam, there were innerspring coils. Instead of having foam layers, innerspring mattresses contain coil systems for support, and these coils give innerspring beds a lot of springiness and bounce.
Innerspring beds aren’t just made with coils, though, they also have thin comfort layers to provide cushion. Usually, these comfort layers are made with foam, wool, feathers, cotton, or other cushioning materials.
Types of Innerspring Coils
Generally, full mattresses should have at least 300 coils, queen mattresses should have at least 400 coils, and king mattresses should have at least 450 coils. The number of coils can impact bodily support and how long the mattress lasts. But it’s not all about the number—these coils vary in structure, and each coil design functions differently.
Hourglass coils are the most common type of mattress coil. Within this category are two subtypes—Bonnell and offset coils. Both of these coils have an hourglass shape, and they are usually wired together to form a continuous chain.
Bonnell coils are associated with traditional innerspring mattresses, and they are less expensive to make. Today, Bonnell coils are still the most prevalent coils in the mattress industry, though they are typically found in less expensive budget mattresses.
The offset design features circles at the top and bottom of each coil, which are flattened to create a hinging action within the mattress core. This design allows the mattress to better conform to the sleeper’s body. They are also less noisy than Bonnell coils.
Pocketed coils are individual springs wrapped in a fabric or foam cover, allowing each spring to move independently. Pocketed coils help reduce noise when sleepers toss and turn, and they can be great for motion isolation and targeted pressure relief.
This design features one continuous wire that is used to construct a row of coils. Each row is then connected using a helical wire. Continuous coil mattresses provide firmer support; however, they are not ideal for shaping the sleeper’s body and motion transfer can be an issue.
Benefits of a Spring Mattress
Innerspring mattresses are time-tested and budget-friendly. Their coils prevent heat entrapment during the night and can provide decent support for joints and pressure points. These mattresses can also be combined with pillow or Euro tops for an extra layer of cushion.
Drawbacks of an Innerspring Mattress
Spring mattresses do not absorb movement or target pressure points very well, and they act as a mattress for pressure points quite like memory foam can. Spring mattresses are also too noisy for some sleepers.
How Memory Foam and Innerspring Mattresses Compare
After looking at the strengths and weaknesses of each mattress type, let’s see how they compare in five essential categories.
Both spring and memory foam mattresses can offer great neck, shoulder, and back support. Memory foam conforms to the body’s natural curves and offers pressure relief to aching joints.
However, spring beds don’t distribute body weight quite like memory foam. So anyone seeking a mattress for joint pain may need a more conforming surface.
If you share a mattress with someone who tosses and turns each night, a memory foam mattress will help absorb that movement so you don’t feel it on your side of the bed. Spring mattresses will likely bounce with movement, resulting in motion transfer and sleep disturbances.
Even if you’re not a restless sleeper, a mattress for couples should isolate motion well, just in case you have to move out of bed in the night.
The coil layers of innerspring mattresses provide great airflow for temperature regulation. Traditionally, these mattresses sleep cooler than memory foam.
However, gel memory foam and plant-based memory foam are designed with breathability in mind to keep sleepers cool during the night. Today, memory foam might be a better choice for hot sleepers.
Because some innerspring mattresses can sink and sag after years of use, memory foam beds are generally considered to be the more durable option. Memory foam mattresses can last up to 10 years, while the lifespan for a spring mattress is usually half that.
However, this varies between manufacturers and mattress types. You can find some of the most durable mattresses with all sorts of materials.
Comfort and Pressure Relief
The highlight of a memory foam mattress is its ability to adapt to the body’s natural curves and target pressure points at the neck, shoulders, and spine. These serve as great mattresses for side sleepers who need extra support at the hips.
Spring mattresses can not do this to the same degree; their metal construction provides much less cushioning than memory foam, and some spring mattresses do not offer much pressure relief at all.
What is the origin of memory foam?
In the early 1970’s, NASA’s Ames Research Center funded a development project designed to create a substance that could help relieve astronauts of the incredible g-forces experienced during lift-off. In the 80s and 90s, mattress manufacturers began experimenting with the new material for consumer use. Memory foam mattresses became especially popular as mattress in a boxes took off.
Does memory foam get softer over time?
Memory foam will eventually soften without you having to do anything, aside from sleeping on it. You won’t have to wait for very long, as memory foam only needs a few days to break in. Raising the temperature in your bedroom can be a good way to soften the memory foam and make it mold to your body more quickly.
How often should I replace my bed?
Depending on your bed, it could last 5-10 years. Generally, memory foam mattresses will last 7-10 years, while spring mattresses last 5-7.
However, it all depends on how well you take care of your mattress. Use a mattress protector and rotate your bed (if the manufacturer suggests it) to increase its lifespan.
How long should I wait before sleeping on a new memory foam mattress?
It takes 4-6 hours for the memory foam to expand 90%, and it could take another 4-6 hours to get close to full expansion. It is recommended to wait 24 hours before sleeping on a memory foam mattress. Still, it won’t hurt the mattress if you break this 24-hour rule.
Should you rotate innerspring mattresses?
Some mattresses need to be rotated every week for the first few months and every few months thereafter. Most mattresses have been designed as “no-flip” mattresses, eliminating the need for end-over-end rotation. An old innerspring mattress can be rotated 2-5 times a year.
We suggest reaching out to the manufacturer if you’re unsure how often to flip or rotate a mattress.
Which is Right for You?
Choosing the right mattress really comes down to personal preference. Both memory foam and innerspring mattresses vary in styles and types to offer support, pressure relief, durability, and temperature regulation.
If you share a mattress, memory foam might be the way to go. If you sleep hot, you may like an innerspring mattress with cooling sheets.
If you’re leaning towards a particular mattress, most retailers now offer free trial periods with the best mattresses, allowing sleepers to test a bed without making a massive commitment. This can add a little flexibility to the process.