Serta iSeries Hybrid 100 Firm Mattress – Is This Firmer Mattress Right For You?

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The new Serta iSeries Hybrid line incorporates a patented foam technology and individually wrapped coils.  They are designed to give the best of both worlds; the pressure relief of foam and the support and contouring of coils.

The 100 Firm Mattress is the firmest model in the iSeries line and offers more support, especially if you sleep on your stomach or back.

This review will go over the construction details and key takeaways of this product in order to help consumers make a more informed decision.

A mattress sits with its certification next to it.

Construction Overview

The Serta iSeries Hybrid 100 is approximately 13.5” high and contains:

  • HyperFeel Surface Design
  • .5” Cool Reaction Gel Memory Foam
  • 1” EverCool Twist Gel Memory Foam
  • 1” Serta Balanced Support Foam
  • 1” EverCool Twist Gel Memory Foam
  • 886 Pro-Support Coil System with Best Edge Foam Encasement

Firmness Level

This mattress is at the firm end of Serta’s firmness scale.  This is the firmest option in the iSeries Hybird series.

The firmness scale for a mattress.

Who Might Want To Consider This Mattress:

  • People who sleep on their stomach or back. This is a very firm model, and firm beds are usually best for people who sleep on their stomach.  Also, it could be a good fit for back sleepers who prefer a firmer mattress and want more support overall.
  • Hot sleepers. This model contains one layer of Cool Reaction Gel Memory Foam and two layers of EverCool Twist Gel Memory Foam.  They both help to dissipate heat, so people shouldn’t be sleeping hot with this mattress.
  • People who want a mattress that is easy to get in and out of. Foam mattresses often collapse as people sit near the edge.  Being a hybrid, the 100 Firm has coils as well, which help give the mattress better edge support.  It also features Best Edge Foam Encasement, so people shouldn’t be rolling out of bed.

Who Might Not Want To Consider This Mattress:

  • Side sleepers. Mattresses on the softer side of the firmness scale are usually best for side sleepers, because they allow sleepers to get the pressure relief they need on their shoulders and hips.  The 100 Firm is a firmer mattress, so it may not give the best pressure relief on shoulders and hips.
  • Those who prefer a soft mattress. Again, this mattress is especially firm and will not suit someone who is looking for a cushiony or plushy, soft mattress.
  • People who are not a fan of hybrid mattresses. There are multiple layers of memory foam in this mattress, and it also contains Serta’s 886 Pro-Support™ Coil System.  If people prefer an all foam mattress or innerspring mattress, this may not be the ideal choice for them because of its hybrid construction.

Related: Check out our overview for Serta’s iComfort memory foam line here.

Most Common Pieces Of Praise

  • Many buyers said that the mattress is firm while simultaneously being supportive. One wrote: “The product is firm and comfortable. My spine remains aligned at night.”
  • Reviewers also like the overall look of the mattress, which is covered in Serta’s HyperFeel Surface Design. “The look is neat and modern,” a reviewer wrote.
  • According to buyers, the Cool Reaction Gel Memory Foam and EverCool Twist Gel Memory Foam layers keep them from sleeping hot. One buyer wrote: “It…helps me stay cool due to the way it is constructed.”

A side, cross-section view of a mattress.Most Common Complaints

  • Some people have found that the mattress is too firm when it arrives, and a few say it took a long time to feel comfortable. “Be sure to give it some time to ‘break in,’” a reviewer wrote. “We ordered a firm and it is firm… but it does relax a bit within the first three months or so.”
  • Due to a normal process called “off-gassing,” the mattress may give off a chemical odor. One reviewer wrote: “I have had this mattress for over a month. The first 4 days, the chemical smell was unbearable. I had to leave the mattress in a room with the windows open and fans on around the clock. By the 5th day, I slept on the mattress but could still smell the chemicals.”
  • Unfortunately, the temperature control technology does not work for everyone who owns the mattress. One buyer said:“It also sleeps very hot, which wakes me up.”

Why Pick This Over Other Serta Models?

This is a hybrid model, which makes it different from Serta models that are either pure memory foam mattresses or purely innerspring coil mattresses.

This is also at the firm end of the Serta firmness scale, so people should pick this model if they sleep on their stomach, or they are a back sleeper who prefers a firmer mattress.

This model contains a cooling HyperFeel Surface Design, which is not always found in all Serta mattresses. Serta describes this as “a touchably soft cover fabric design that brings the cooling, comforting and supportive feel of memory foam right to the top of the bed.”


The Serta iSeries Hybrid 100 is approximately 13.5” high and contains a HyperFeel Surface Design, .5” Cool Reaction Gel Memory Foam, 1” EverCool Twist Gel Memory Foam, 1” Serta Balanced Support Foam, 1” EverCool Twist Gel Memory Foam, and a 886 Pro-Support Coil System with Best Edge Foam Encasement.

Hot sleepers, stomach sleepers, and back sleepers who like more support, may enjoy this firmer mattress from the iSeries Hybrid line.

Check out our comprehensive review of the Serta iSeries Hybrid series here.  

All images from Serta

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Marten Carlson

Marten is Senior Editor at Mattress Clarity. He covers the mattress industry as well as sleep science news. He is specifically interested in the connection between sleep and overall health.Marten has written for media publications like Consequence of Sound and received a master’s degree in Film Studies from Emory University.He comes from Franklin, Indiana, and spends all the time he can writing, directing, and acting in films. He has directed genre short films and features. His newest film, Starlets, recently premiered at the River Town Film Festival in Clinton, NJ. He also stars in the upcoming thriller, Sour Bear. His next film, At The Hop, is a hot rod actioner with a horror twist.