Comfort IQ™ · Scored on what actually matters
NM® Cozy Air™ 8″ 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 NM Cozy Air 8" Medium Firm Memory Foam Mattress scores 9.2 for durability, and the reason is structural: seven of its eight inches are high-density support core. Soft comfort foam is the part of any mattress that gives out first, and this build carries a single inch of it - cooling gel memory foam, the densest in the Cozy Air line - resting on a core built to resist exactly that. Responsiveness is exceptional at 9.8, so the surface lets go the instant you move instead of holding the shape of your last position, and cooling reaches 8.6 through an open 3D Air-Knit Performance Fabric over gel-infused foam. At a medium 6/10 it reads supportive first and soft second - what back and stomach sleepers, platform frames and guest rooms actually want, with 365 nights at home to confirm it.
Performance Scores
An 8.5 overall with an unusual shape for a slim bed: responsiveness tops out at 9.8 and durability at 9.2, both earned by how little soft foam sits in the stack. Pressure relief is the honest floor at 7.9 - very good, but a one-inch comfort layer cradles shallow on purpose.
Responsiveness9.8
Move and the surface lets go - no crater to climb out of.
Durability9.2
Only an inch of soft foam to compress - the feel holds.
Cooling8.6
Open-weave cover over gel foam - heat leaves the surface.
Edge Support8.5
Steady across the sleeping field; the rim gives when you sit.
Motion Isolation8.3
A partner's roll dies where it starts.
Spinal Support8.0
The core keeps the hips up at a medium 6/10.
Pressure Relief7.9
A shallow, supportive cradle rather than a deep hug.
Off-Gassing 8.0 Brand 7.0 Sleep Trial 10.0 Value 9.2
In National Mattress's in-house Comfort IQ analysis, the NM Cozy Air 8" Medium Firm scores: Overall 8.5/10, Cooling 8.6/10, Pressure Relief 7.9/10, Motion Isolation 8.3/10, Edge Support 8.5/10, Responsiveness 9.8/10, Spinal Support 8.0/10, Durability 9.2/10.
Best For
Back and stomach sleepers of average build Spinal support scores 8.0 and sinkage stays in the 1.86-2.87 inch range - there is not enough soft foam above the core to let the hips drift below the shoulders.
Combination sleepers who reposition all night Responsiveness at 9.8 is the highest score on this bed. The surface is mostly recovered in under 1.70 sec., so a position change is a movement rather than an escape.
A compact build that is not a compromised one Eight inches is usually where corners get cut - a thin skin of comfort foam over a low-grade filler core. This is the reverse: genuine cooling gel memory foam over a real high-density core, under a proper 3D Air-Knit cover. Value scores 9.2 on material quality alone.
Couples sharing with a restless sleeper Motion isolation scores 8.3 and disturbances settle inside 0.50-0.71 seconds. Nothing in this bed carries energy sideways.
Platform frames, bunks, and rooms where height matters Durability scores 9.2 on a build where seven of eight inches are structural. A low total height costs nothing in longevity here.
Considerations
Pressure relief 7.9 - the cradle is shallow by design. One inch of comfort foam is what makes the durability and responsiveness scores possible, and it is also the limit. Dedicated side sleepers who want a shoulder to disappear into the bed will want more than eight inches can carry; the 12" Cozy Air cradles considerably deeper.
Edge support 8.5 - an all-foam rim with nothing bracing it. Edge sinkage runs 3.52-5.59 inches. Sit on the side to pull on socks and the foam under you compresses; sleep tight against the rim and it reads softer than the middle. If you perch on the edge daily, a coil-encased bed holds firmer there.
Spinal support 8.0 - eight inches is a shallow total build. Heavier sleepers will find less material here than they want for long-haul support, and there is no zoning to treat the shoulder and the hip differently. Average-weight sleepers will not meet that ceiling.
Feel & Firmness · 6/10 Medium
The NM Cozy Air 8" Medium Firm reads a medium 6/10 - supportive first, soft second. One inch of cooling gel memory foam blunts the contact points without letting you settle in, and the 7-inch NM HD+ high-density core beneath is what you actually rest on. The surface gives at the skin and holds at the frame: you feel the cushioning, but you sleep on top of this mattress rather than down inside it. It is silent for life, too - with no spring network inside, nothing can creak, ping, or develop the squeak an innerspring earns as its parts wear.
Cooling 8.6
Cooling scores 8.6 on the NM Cozy Air 8": peak surface temperature holds in the 30.2-33.0 °C range - a climb of 8.2-11.0 °C over where it started - then falls back to 25.2-29.4 °C by morning. Against the direct-to-consumer field's 32.39 °C median peak, that lands at or below the middle of the pack. Heat leaves through the cover first: the 3D Air-Knit Performance Fabric is a lofted, open weave rather than a dense quilted panel, so air moves through the top instead of stalling against it, while the inch of gel memory foam pulls warmth off the contact points. Eight inches helps too - less foam between you and the room means less material holding heat.
Pressure Relief 7.9
Pressure relief scores 7.9, with sinkage settling in the 1.86-2.87 inch range - a shallow, supportive cradle rather than a deep hug. The inch of cooling gel memory foam takes the hard edge off the hip and shoulder without letting either drop through to the firm foam beneath, which is the assignment for a medium 6/10 at this height. Back and stomach sleepers get the most from it: enough contouring to soften the contact points, not enough to let the midsection fall out of line.
Motion Isolation 8.3
Motion isolation scores 8.3 on the NM Cozy Air 8", with peak transfer in the 1.24-4.53 m/s² band and whatever travels dying out inside the 0.50-0.71 second window. No spring network means no path sideways: a continuous stack of gel memory foam over high-density support foam takes a roll or a climb-out at the point of contact and ends it there. One caveat - National Mattress's acceleration bench reads at roughly half the scale of the widely published direct-to-consumer method, so trust the ranking, not a head-to-head against a number from elsewhere. For a light sleeper beside a restless partner, movement stays where it started.
Edge Support 8.5
Edge support scores 8.5 on the NM Cozy Air 8", with perimeter sinkage of 3.52-5.59 inches. That is an all-foam rim with no coil ring or encasement behind it, and at eight inches there is less of it than a taller bed carries: sit on the side and the foam under you compresses; sleep tight against the rim and it reads softer than the middle. That is the build, not a flaw - the high-density core keeps the give gradual rather than sudden, and across the main sleeping field it is a non-issue.
Responsiveness 9.8
Responsiveness is the standout at 9.8. The NM Cozy Air 8" is mostly recovered in under 1.70 sec. and completely back in under 3.55 sec., so changing position never means climbing out of the impression you just made. Bounce compression sits in the 4.57-6.75 inch range, rebound under 5.49 inches, total travel 5.86-10.60 inches. That is the payoff of one inch of gel memory foam over a firm high-density core: the contact points soften, but there is not enough foam to produce the slow, sinking quicksand feel that thicker all-foam builds are known for. Combination sleepers notice it first.
Off-Gassing 8.0
Off-gassing scores 8.0 on a 12-24 hours window - the direct-to-consumer field's median sits nearer six days. Every foam in the NM Cozy Air 8" is CertiPUR-US certified, independently tested for low VOC emissions and made without formaldehyde, mercury, lead or ozone depleters. It arrives compressed in a box, so unboxing brings a mild new-foam smell; leave it unwrapped in a room with normal air movement and it clears within the day.
Sleep Position & Body Weight Fit
Back and stomach sleepers of average build are the natural fit for the NM Cozy Air 8" Medium Firm: spinal support scores 8.0, and sinkage of 1.86-2.87 inches keeps the hips level with the shoulders instead of letting the midsection drift. Combination sleepers do well on the 9.8 responsiveness. Side sleepers of light to average weight will find the medium 6/10 workable, though pressure relief at 7.9 reflects a cradle that stays shallow - a shoulder rests on this bed rather than disappearing into it. Heavier sleepers should know eight inches is a shallower total build than they will want for long-haul support, with no zoning to treat the shoulder and hip differently.
At a Glance
Type · Foam Firmness · 6/10 Medium Height · 8″ Comfort layer · 1″ Fiberglass-free CertiPUR-US certified Made in · Canada Trial · 365 nights Delivery · Free on orders over $199
Full construction, per-size dimensions and coil counts are in the product description above. View 365-night trial details.
Frequently Asked
Does the NM Cozy Air 8" Medium Firm sleep hot?
No. Cooling scores 8.6, with the surface peaking in the 30.2-33.0 °C range and settling to 25.2-29.4 °C by morning. Two things drive it: an open-weave 3D Air-Knit cover that lets air pass through the top, and a slim eight-inch build that holds less heat than a thicker one.
Will I feel my partner move on the NM Cozy Air 8"?
Rarely. Motion isolation scores 8.3, and a disturbance is gone within 0.50-0.71 seconds. This is an all-foam bed, so there is no spring network to pass energy along - a roll or a climb-out is absorbed where it lands instead of travelling across to your side.
Is the NM Cozy Air 8" Medium Firm too firm for side sleepers?
For light to average-weight side sleepers, no - a medium 6/10 with 1.86-2.87 inches of sinkage works. But pressure relief scores 7.9, the lowest score on this bed, and the cradle stays shallow. Dedicated side sleepers who want the shoulder to sink in should look at the 12" Cozy Air.
Can I try the NM Cozy Air 8" at home before committing?
Yes - 365 nights, which is why sleep trial scores 10.0. That is a full year on your own base at your own room temperature, and it matters here: a medium 6/10 reads differently in week six than on night one. Free delivery on orders over $199.
Is eight inches thick enough to last as an everyday bed?
Yes. Durability scores 9.2, and the reason is the ratio: seven of the eight inches are high-density support core. Soft foam is what compresses into a body impression over time, and there is only one inch of it here, sitting on a core built to resist that.
