Serta iSeries Hybrid Mattresses — Our Expert Overview (2024)

Note: This is not a review. This is our plain-English explanation and overview of the current Serta iSeries Hybrid mattresses.

If you’d prefer to watch rather than read, watch our Serta iSeries Hybrid Mattresses Overview video.

Serta iSeries Hybrid Mattresses: Common Attributes

Serta's iSeries Hybrid collection of four mattresses include layers of memory foam atop a pocketed coil support unit. These iSeries mattresses are found exclusively at Mattress Firm. In terms of features and materials, the iSeries beds have some features in common with the Serta iComfort Hybrid (2021-2023) mattresses, so you might want to check out our page on those as well.

From a features standpoint, a coil base means that these hybrid models are pretty bouncy. The memory foam on top can negate some of that deep bounce, while adding pressure-relieving properties, along with conformance and cushioning.

Serta is using its latest foams in these iSeries mattresses with a variety a features intended to help you sleep cool. Serta indicates the extent of each model's cooling features with embroidered snowflakes on the side panel of each mattress.

In addition to overall feel, the iSeries mattresses also vary by height, by cooling features, and by price.

Memory Foams

Serta is using a variety of its memory foams in the iSeries mattresses. The exact combination and amount of foams is how Serta varies the feel and cushioning between models.

Among the foams you'll see are Serta's Carbon Fiber Memory Foam. which includes strands of carbon, a known conductor of heat that's intended to help draw heat from the body. This particular foam is present in each of the iSeries models, sometimes with a coating of phase-change material that's further intended to help keep you cool (called the UltraCold System).

The Carbon Fiber Foam is a slow-responding memory foam, so it does have a lot of the 'melting' quality that you identify with memory foam.

Other foams you may see include Serta's Gel Active memory foam, EverCool Fuze and EverCool Supreme memory foams. All are used in combination with the Carbon Fiber Foam, depending on the model.

UltraCold System

A variation of the Carbon Fiber Memory Foam, Serta's "UltraCold System" is comprised of the same carbon fiber-infused foam, but with an added layer of phase change material on top.

We have seen phase-change coatings used more and more often in mattresses; you can liken it to wax beads covered in a casing. When cool, they feel noticeably cool to the touch, and it takes much longer for your body to warm them than it would a plain foam. This type of phase-change coating is intended to keep you feeling cooler longer while you fall asleep.

Here's what the phase-change coating look like on top of the UltraCold System foam.

Pocketed Coil Support Units

The iSeries Hybrid collection all feature a pocketed coil support unit with 1,025 coils in a queen-size bed. Serta varies the spring strength to change up the firmness levels of the mattresses.

You'll find plenty of deep bounce in all these beds. The top foams tend to absorb motion up near the surface, but once you drop your weight on the bed, you'll notice the bounce.

Around the edge of the bed on all four sides is a 4" foam edge support, intended to boost stability right along the edge.

Max Cold Covers

All four of the mattresses use the same cover, which Serta called Max Cold. These include high-density polyethylene fibers within the fabric, giving it a slight coolness to the touch. Think of how a high density material like marble feels inherently cooler than a lower density material like wood. Similarly, the inclusion of higher density fibers in these mattress covers gives them a similar quality of coolness.

This is one big difference between Serta's iSeries Hybrid models versus its iComfort Hybrid models. The Max Cold cover is included on all of the iSeries mattresses while it's only featured on the most expensive iComfort Hybrid mattresses.

Serta iSeries Hybrid 1000 Medium

The base model in the iSeries Hybrid collection, the 1000 Medium, also felt like a Medium on our comfort scale. If you don't like sinking into a mattress really deeply, but also don't like feeling like you aren't sinking at all, a Medium mattress on our scale offers a good blend of the two. You do get some of that slow-responding, sinking-into-the-bed feeling from the memory foam.

This is a 12" tall mattress, with a total of 2.5" of memory foam; there's an inch of the Carbon Fiber Memory Foam plus another 1.5" of Serta's Deep Reaction memory foam.

The two snowflakes embroidered on the side of the bed mean that the mattress has two of Serta's signature cooling features; in this case, the Max Cold cover with high-density polyethylene fibers plus the carbon heat conducting properties in the memory foam.

Serta iSeries Hybrid 2000 Firm

Stepping up in the line, the 12.5" tall iSeries Hybrid 2000 includes the same Carbon Fiber Memory Foam but more of it -- 1.5". Under that is another 1.5" of Serta's Gel Active Memory Foam. Like carbon, gel is a known conductor of heat, so it's intended to add some extra heat-dissipation qualities. With the addition of the Max Cold cover, that's three cooling features, so three snowflakes on the side of the cover.

The iSeries Hybrid 2000 is classed as a Firm by Serta, but we didn't think it felt significantly more firm than the iSeries 1000. We would still call the iSeries 2000 a Medium on our scale. It does, however, have a little more of that slow-responding memory feel sensation.

Serta iSeries Hybrid 3000 Medium

Continuing up the line, the 13.5" tall iSeries 3000 Medium has a total of 4" of memory foam. There's 1.5" of the Carbon Fiber Memory Foam, plus 3.5" of additional Serta memory foams.

This model adds a layer of phase-change material on top of the carbon-fiber foam; Serta calls this their UltraCold System. It's intended to help keep you cooler as you fall asleep. You also get the same cooling cover, for a total of three snowflakes corresponding to cooling features.

The 3000 Medium, in our view, is quite a bit softer than the 1000 Medium or the 2000 Firm. On our scale, we would call it a Medium Soft. You get a lot of that slow-responding memory feel, and a lot of cushioning and conformance, where the mattress hugs around your body's curves.

Serta iSeries 4000 Plush

The top of the line iSeries Hybrid mattress is the 4000 Plush, a 14.5" tall mattress with 4.5" of total memory foam.