Eight Sleep Mars+ Mattress Review (2019)

Sleep Tracker

The "plus" sign in "Mars+" is for the included Sleep Tracker, the big selling feature from Eight Sleep. The tracker has several components. The 'receiver' that collects your data comes as a series of sensors embedded in a mattress cover that installs right on top of the Mars mattress (it goes on just like a mattress pad). You can see the wires and sensors in the cover, but our tester could not feel them at all. The top part of the cover unzips and is washable.

The mattress pad/sensor plugs into a small receiver unit, which in turn connects to an app, which serves as your dashboard and main interface for the sleep data that's collected, and also serves as a controller for the Sleep Tracker. For example, you can use the tracker as a heating pad, and set the app to start warming the bed at a certain time. You can even control both sides of the bed independently.

What can you  track with the Sleep Tracker? It can monitor your sleep, and tell when you are sleeping soundly or fitfully. It can tell you how often you wake up, your heart rate and respiration rate. It tracks total sleep time, and knows how long it took you to fall asleep. Based on the data, the app can make recommendations to improve your sleep quality. It can connect and sync with many other applications and trackers, and can be use to program the Sleep Tracker as a heating blanket.

Comfort & Feel

There are three aspects that make up our assessment of comfort and feel. We call these "preference-based characteristics" because no rating here is better or worse – rather, the attributes that are most desirable to you will be determined solely by your personal preferences. We apply the same classification standards to each mattress so you can more easily compare apples to apples.

Softness ( what’s this )

Keep in mind that what mattress companies call “firm” or “soft” is a purely a preference. All mattresses should be supportive and promote healthy spinal alignment. Whether a mattress is fluffy and squishy (what mattress companies call soft or plush), or less so (what companies call firm), is purely down to your personal needs and preferences.

We classify the Mars+ as a medium firm mattress

Not sure what softness is best for you? Take our Mattress Match Quiz and find out.

Cushioning Depth ( what’s this )

This refers to how deeply you sink into the mattress or feel cradled or hugged, versus a feeling of floating on top of the bed. This is definitely more of the latter. When we place our 16-lb. bowling ball atop the mattress, it did not sink in as much as it did with some of the other mattresses we’ve recently tested. And our tester, lying on top of the bed, felt cushioning was a bit shallower than some competing mattresses with deep pillowtops and plush top layers.

The Mars+ mattress has what we would term medium cushioning -- average among mattresses, but giving you a big more of a floating feeling as opposed to sinking in deeply.

Responsiveness ( what’s this )

Responsiveness refers to how quickly a mattress recovers its shape after being compressed. When you press your hand into the mattress, for instance, then remove it, does it take several seconds for the mattress to return to flat, or does it recover immediately?

The Eight Sleep Mars+ mattress does not contain any memory foam, so it's no surprise we did not note any of that slow, melting into the bed sensation you get with memory foam. Rather, the bed springs back into shape very quickly.

We also tested bounce;  the pocket springs in this mattress pushed our tester back into the air when he dropped his weight on the bed, so if you like a mattress with some bounce, the Mars+ has it.

Back Support & Pressure Relief

The two things that you should always be sure to get from your mattress are spinal alignment (commonly thought of as "back support") and pressure relief. Unfortunately, no mattress will deliver these two things equally well for all sleepers. In particular, spinal alignment and pressure relief capabilities will vary across sleepers with different weights, body shapes, and sleep positions. To help you determine how this mattress will perform for you, we break down our spinal alignment and pressure relief assessments by sleeper type.

In our evaluations, the Eight Sleep Mars+ mattress performed well in all sleeping positions for our tester. If you sleep in a variety of positions, or your partner sleeps in different positions that you, the Mars+ might be a good choice. We tested the Mars+ hybrid mattress and the Jupiter+ all-foam bed at the same time, so our observations contrast between the two. Generally, they are more similar than different.

Spinal Alignment

The key to good back support is maintaining proper spinal alignment while you sleep. This means that the mattress should hold your spine in roughly the same position it's in when you're standing. The ability of a given mattress to do this will generally depend on your weight, sleep position, and body shape.

Here is how we break down the spinal alignment of the Eight Sleep Mars+ mattress.

Back Sleepers:

While our tester was on his back, he noted that his hips sank just deeply enough to create a perfectly neutral spine, while he felt the mattress did a nice job reaching up to support his lumbar curve. We feel that sleepers of a wide weight range would have a similar experience, and we did not have concerns that heavier sleepers might not be supported enough.

We found this to be true for both the Mars+ and the Jupiter+ mattresses, though our 200-lb. tester did have a preference for the firmer hybrid bed (the Mars+).

Side Sleepers:

For side sleeping, our tester also felt the Mars+ was supportive. He felt his shoulder sinking into the mattress enough to create good spinal alignment. He did feel that pressure relief was a bit better on the all-foam Jupiter+ mattress, but both mattresses performed well. If you are mainly a side sleeper, you might want to also see our review for the Eight Sleep Jupiter+ mattress.

Stomach Sleepers:

Achieving good spinal alignment for stomach sleepers can often be trickier as the hips can tend to sink down too far with some mattresses, but our tester felt well supported in this position as well. For those who sleep primarily on their stomachs, our tester preferred the Mars+ over the all-foam Jupiter+ mattress.

Pressure Relief

Overall, we found the pressure relief offered by the Eight Sleep Mars+ mattress to be good, but if you have experienced joint issues in the past, or are concerned about hot spots or pressure points, especially if you are a heavier individual, see our review for the Eight Sleep Jupiter+ all-foam mattress.

Other Features

Beyond the preference-based characteristics of comfort and feel, and the body matching for spinal alignment and pressure relief, a mattress will have a number of other attributes that can make it a better or worse choice for you. We call these "priority-based characteristics" because they are areas in which a mattress can be better or worse, but that will have differing amounts of importance to each sleeper. So, determining how much importance to give to these features will be entirely a matter of your own personal priorities. As always, we apply the same ratings standards to each mattress so you can more easily compare apples to apples.

Motion Isolation ( what’s this )

With a bowling pin standing upright on the Eight Sleep Mars+ bed, we tested motion isolation by dropping a 16-lb. bowling ball on it, as well as the whole weight of our 200-lb. tester.

In both tests, the bowling pin wiggled a bit but never fell. That's impressive for a mattress that includes coils, but because this bed uses pocket springs, each spring moves independently, limiting motion transfer.

We felt that the Mars+ bed would be a good choice for couples who don’t want to feel their partner getting in and out of bed.

Temperature ( what’s this )

For most people, we do not think the Mars+ mattress will feel hot. Because of the spring support layer, the mattress has more natural air flow than an all-foam bed, even though there's four inches of foam on top of the springs. If you have a known issue with sleeping hot, you might consider a mattress with less foam, but for most people, we do not think the Mars+ mattress will feel hot.

Edge Support ( what’s this )

Ease of Repositioning ( what’s this )

One of the highlights of the Eight Sleep Mars+ mattress, for our tester, was ease of movement, which owing to its high responsiveness, was almost effortless. If you tend to change positions a lot, the Mars+ mattress performed extremely well in our view.

Green Features ( what’s this )

For mattress shoppers concerned with the use of natural materials, sustainable manufacturing practices or the like, we offer our subjective evaluation of any efforts taken by the company to make the mattress more green, healthy, or safe. 

In the case of Eight Sleep, the company makes no claims about the use of natural materials, and is up front that its latex foam is synthetic. All of the foams used are certified to the CertiPUR-US standard, which verifies that a material has low VOC off-gassing as well as a lack of chemicals and other substances regulated by the CPSC.

Adjustable Base Compatibility ( what’s this )

We did not specifically test the Eight Sleep bed with an adjustable base. However, the company does say that it can be used on one, and it does sell an adjustable base.

Price, Value & Longevity

How Much Does a Mars+ Mattress Cost?

Prices shown are list prices. Remember that GoodBed keeps our site current with the best available discounts on all online mattresses, many of which are exclusive discounts for our readers. 

Note: These are the last selling prices prior to the Mars being discontinued.

Delivery

• Free delivery 

Eight Sleep includes free delivery, which is not particularly unusual among its competitors.

Returns

• 100-day trial period
• Full refund

Eight Sleep offers buyers a 100-day trial period. Returns within the trial period are free, but you'll need to provide proof of donation or disposal. Eight Sleep will help you find a place to donate the mattress.

Warranty

• Warranty Length: 10 years
• Indentation Coverage: 1” and above

One of the biggest, if not THE biggest complaints about any mattress from consumers regards body impressions—the inability of a mattress to spring back, eventually creating a low spot/sinkhole in the mattress. As such, mattress warranties all contain a term defining how big a sag or ‘body impression’ (measured when no one is on the mattress) is considered a defect, and thus covered under the warranty. The industry standard for innerspring mattress is 1.5”. Eight Sleep has chosen to cover indentations that meet or exceed 1”. Practically speaking, that means any softening or sagging would need to be at least that deep before the warranty would offer you protection.