SERTA® iComfort® 11.5" Firm Memory Foam Mattress

Comfort IQ™ · Scored on what actually matters

SERTA® iComfort® 11.5″ Firm Memory Foam Mattress — Performance & Feel

Comfort IQ™ scores eight dimensions 0–10 from National Mattress's in-house testing + construction — the same scale on every model, so two beds compare on what actually matters. Results vary by body type, base, and room temperature.

The SERTA® iComfort® 11.5″ Firm Memory Foam Mattress scores 8.9 for spinal support, with zoned support tuned down the length of the bed to lift the heavier midsection. A firm 8/10 surface over a dense full-width foam core holds the spine on a neutral line — the alignment sweet spot most back and stomach sleepers do best on. It pairs that support with top-tier durability (10.0) and a quick, clean break-in, while a single inch of memory foam adds gentle, easy contour and pressure relief lands at 7.3. As the most accessibly built firm option in the iComfort lineup, it is a smart-value pick for back and stomach sleepers who want dependable, on-top support that lasts.

Performance Scores

In National Mattress's in-house Comfort IQ analysis, the iComfort 11.5″ Firm scores: Overall 8.3/10, Cooling 8.1/10, Pressure Relief 7.3/10, Motion Isolation 8.1/10, Edge Support 8.8/10, Responsiveness 8.9/10, Spinal Support 8.9/10, Durability 10.0/10.

Best For

Considerations

How It Performs — The Measured Detail

Feel & Firmness · 8/10 Firm

This is a firm bed, 8 out of 10, with a slim comfort layer. A single inch of memory foam over a dense Serta foam core gives just enough surface give to take the edge off, then a solid platform underneath. The feel is supportive and on-top — the memory foam contours gently at the contact points but you do not sink in. Zoned support tunes the firmness along the length of the bed, so the heavier midsection is lifted while the shoulders and legs ease in. A firm, supportive surface for sleepers who want to rest on top.

Cooling 8.1

For an all-foam bed with no coil channels to move air, the iComfort 11.5″ Firm holds its surface temperature well. Peak surface temperature measured 32.3 °C, with the warming over baseline measured at 10.3 °C — a respectable result that comes entirely from the materials rather than airflow. A graphite-treated comfort foam pulls heat off the very layer your body rests against, and the breathable CoolFeel cover keeps the touch from turning sticky. The rise lands toward the upper part of that window, so this runs comfortably mainstream rather than genuinely cool, settling to a measured 28.4 °C overnight.

Pressure Relief 7.3

Even with its firm character, this iComfort cradles a touch more than its on-top feel suggests. Sinkage measured 2.41 inches, enough for the single inch of memory foam to wrap the shoulders and hips and spread contact pressure without ever letting you pass through to the dense core beneath. Rated firm at 8/10, it gives just a little at the contact points and then a solid, supportive platform underneath — the profile back and combination sleepers tend to settle into most comfortably. A dedicated side sleeper who needs the shoulders to drop deeper would prefer a softer bed.

Motion Isolation 8.1

Sharing this bed with a restless partner is no problem. Peak transfer measured 2.47 m/s² and the movement quiets down within the 0.54–0.76 second band — both toward the still end of the scale. This is exactly where memory foam earns its reputation: the comfort layer soaks up a partner's shift and damps it before it can travel across the surface, so a roll-over on one side barely registers on the other. Couples and light sleepers will find it genuinely calm, and with no springs inside it stays silent.

Edge Support 8.8

Sit on the very perimeter and this foam bed gives more than a steel-encased border would — edge sinkage measured 5.12 inches, the expected trade-off for an all-foam build with no reinforcement. What rescues it is the hands-on lying-support feel, which rates good thanks to the firm overall surface and a substantial core. The extreme edge compresses when you perch, but the usable sleeping area stays steady closer to the sides than a plush foam bed could manage. For a pure-foam construction, that is a strong, usable perimeter.

Responsiveness 8.9

This is classic memory-foam character — a slow, deliberate melt rather than a springy push back. Bounce total travel measured 6.37 inches, and the surface mostly recovered in a measured 0.73 seconds to reshape after you move off it. You settle in, the foam holds you there, and it eases back gradually. If you want a surface that cradles and stays put beneath you, this is precisely the right feel; anyone who prefers a lively lift when changing positions would be happier on latex.

Off-Gassing 9.0

Break-in odor here is about as faint as mattresses get — the off-gassing clears in under 12 hours, well short of what is typical. A few things keep it down: the foams are CertiPUR-US certified to strict low-emission limits, the bed is built in Ontario and delivered flat rather than tightly compressed, so little is sealed up waiting to release, and the thin comfort layer simply means less foam to air out. Most sleepers will notice essentially nothing from the very first night.

Sleep Position & Body Weight Fit

Back and stomach sleepers are the natural fit — the firm 8/10 surface and zoned support hold the spine level, lifting the midsection where it tends to dip. Combination sleepers get a steady, supportive platform to move on. Average and heavier bodies are well held with no hammocking; lighter sleepers will find it genuinely firm. Dedicated side sleepers who need deep shoulder and hip cushioning are the one group better matched to a softer model.

At a Glance

Full construction, per-size dimensions and coil counts are in the product description above. View 365-night trial details.

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