Comfort IQ™ · Scored on what actually matters
SERTA® iComfort® 13″ Medium 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 13″ Medium Firm Memory Foam keeps a partner's movement off your side, measuring as low as 1.04 m/s² of transfer in our in-house testing. An all-foam build with a true medium feel, it cradles the shoulders and hips for real pressure relief while a dense, zoned core keeps the spine neutral — a balanced all-rounder for couples and most sleeping positions. As with any coreless bed, the seated edge is its softest point.
Performance Scores
An 8.5 overall with no real weak axis — strong scores straight across, led by quiet all-foam motion isolation and a lively recovery, with the foam border the only soft note.
Responsiveness9.2
A cushioned, gentle return — cradling rather than springy, by design.
Durability9.2
High-density foam over a dense core resists the early soft-spot sag.
Edge Support8.7
Held up better than most foam beds — usable sleeping surface to the rim.
Cooling8.6
CoolFeel cover + graphite-treated foam pull heat from the surface.
Spinal Support8.2
A dense, zoned core holds the spine neutral across the whole body.
Motion Isolation8.2
Foam swallows movement at the source — a restless partner won't wake you.
Pressure Relief8.1
A medium cradle that relieves the shoulders and hips without over-sinking.
Off-Gassing 9.0 Brand 8.8 Sleep Trial 10.0 Value 5.4
In National Mattress's in-house Comfort IQ analysis, the iComfort 13″ Medium Firm scores: Overall 8.5/10, Cooling 8.6/10, Pressure Relief 8.1/10, Motion Isolation 8.2/10, Edge Support 8.7/10, Responsiveness 9.2/10, Spinal Support 8.2/10, Durability 9.2/10.
Best For
Couples Motion Isolation 8.2 — the memory layer swallows a partner's movement at the source, so a restless sleeper or a dog won't jostle you awake.
Sleepers who want one bed for every position Firmness 6/10 — a true medium is the broadest-fitting feel, supportive enough for backs yet cushioned for sides.
Buyers who want a cradling foam feel that lasts Durability 9.2 — high-density foam over a dense core resists the soft-spot wear that retires cheaper memory beds early.
Light sleepers in a shared or quiet room Off-Gassing 9.0 + all-foam silence — no coils to creak and a clean, fast break-in.
Considerations
Softer seated edge (Edge Support 8.7) With no coils to reinforce the perimeter, an all-foam bed softens at the edge when you sit on the side to tie your shoes — this one held up better than most, graded Good, but should not be expected to feel like the rock-solid sit of a spring bed.
Melt-in, not springy (Responsiveness 9.2) The memory comfort layer recovers slowly and gently rather than throwing you back — ideal if you want pillowy and cushioned, but a hybrid suits you better if you crave spring underneath you.
How It Performs — The Measured Detail
Feel & Firmness · 6/10 Medium
The iComfort 13″ Medium Firm sits at a true medium — 6 out of 10 — the most broadly comfortable feel there is. It is firm enough to stop the hips dropping out of line, soft enough that the shoulders still settle in, giving the wrapped, cradling hug a memory comfort layer is built for without tipping into a deep sink.
Cooling 8.6
Cooling is a genuine win for an all-foam bed like the iComfort 13″ Medium Firm, since a foam core breathes far less than a coil bed and must do its cooling work through the surface. Peak surface temperature stays in the 30.3–33.0°C range, with the rise over baseline in the 8.3–11.0°C band — it warms a bit faster early before it settles. The CoolFeel fabric cover and graphite-treated comfort foam pull heat from the layer your body touches, and it lands cool by the end of the night.
Pressure Relief 8.1
At a true medium feel the iComfort 13″ sits in the sweet spot for spreading pressure off the shoulders and hips, with sinkage settling in the 1.98–2.99 inch range — a deep, enveloping immersion that tracks with the wrapped, cradling hug the memory layer gives. The conforming foam lets the heaviest parts of the body settle in and float rather than press against a hard surface, while the medium base keeps you from sinking past comfortable.
Motion Isolation 8.2
Motion isolation is where the all-foam construction simply wins. Transferred motion measures in the 1.04–4.33 m/s² range, landing at the quiet end, with the surface settling in the 0.54–0.76 second band. The memory layer over a dense foam core swallows movement at the source instead of letting it ripple across, and with no springs there is nothing to carry a partner's shift to your side. Share the bed with a restless partner, or a dog that reorganizes itself all night, and you sleep through it.
Edge Support 8.7
Honesty first: with no coils to reinforce the perimeter, an all-foam bed softens at the edge, and you feel it when you sit on the side — edge sinkage measures in the 3.82–5.88 inch range. That said, this iComfort held up better than most foam beds, with the lying-support behavior grading Good rather than the Fair the all-foam build implies. You still get usable, sleepable surface right out to the rim.
Responsiveness 9.2
This is a melt-in feel, not a trampoline, and that is by design. Bounce total travel measures in the 5.01–9.74 inch range, but with the memory comfort layer absorbing energy rather than throwing it back. It returns to shape slowly and gently, with full recovery in the 0.27–4.07 second band, giving the classic cradling sink memory-foam buyers come for — pillowy and supportive over quick and lively.
Off-Gassing 9.0
New-mattress smell is a non-issue, with the off-gas period clearing in under 12 hours. The foams are CertiPUR-US certified to strict low-VOC limits, and the bed is built locally in Ontario then delivered flat rather than tightly compressed in a box for weeks — less compression means less trapped odor to release. Unpackage it, let it breathe a day or two, and you are sleeping on it clean.
Sleep Position & Body Weight Fit
The medium 6/10 build is the broadest-fitting feel of the lineup. Back sleepers get neutral support from the dense, zoned core; side sleepers get the shoulder-and-hip cradle from the conforming top; combination sleepers get a surface that suits both. Average-weight bodies are the ideal match, while lighter sleepers feel a touch more cushion and heavier sleepers still get steady support without bottoming out.
At a Glance
Type · Foam (memory) Firmness · 6/10 Medium Height · 13″ Comfort layer · Memory foam Fiberglass-free CertiPUR-US certified Made in · Canada Trial · 365 nights Delivery · Free on orders over $199
Full construction, per-size dimensions and layer details are in the product description above. View 365-night trial details.
Frequently Asked
Is the Serta iComfort 13″ Medium Firm good for couples?
Yes — it scores 8.2 for motion isolation, measuring as low as 1.04 m/s² of transfer. The memory layer over a dense foam core swallows movement at the source, and with no springs there is nothing to carry a partner's shift across the bed. A restless partner won't wake you.
What sleeping position is the iComfort 13″ Medium Firm best for?
All of them, which is the point of a true medium. The 6/10 feel is firm enough to keep back sleepers aligned (spinal support 8.2) and cushioned enough to relieve a side sleeper's shoulder and hip (pressure relief 8.1), making it the broadest-fitting bed in the lineup.
Does the iComfort 13″ Medium Firm sleep hot?
No — it scores 8.6 on cooling and peaks at 32.3°C, strong for an all-foam bed with no coils to circulate air. A CoolFeel fabric cover and graphite-treated comfort foam pull heat out of the surface, and it settles cool by the end of the night.
Does the iComfort 13″ Medium Firm feel springy or sink-in?
Sink-in. It is a melt-in memory feel that recovers slowly and gently rather than springing you back (responsiveness 9.2). If you want a pillowy, cradling surface this delivers it; if you crave bounce underneath you, a hybrid with coils would suit you better.
Can I try the iComfort 13″ Medium Firm at home first?
Yes — it comes with a 365-night sleep trial, a full year to test it through every season. A memory-foam bed takes a few weeks for your body to adjust to, so the trial gives you the runway to be sure. Delivery is free on orders over $199.
