Sierra Sleep by Ashley
Sierra Sleep Millennium 2.0 Hybrid 14 Inch Mattress
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The Sierra Sleep Millennium 2.0 Hybrid 14 Inch is built for the sleeper who wants a genuinely plush feel without giving up the support of a coil system underneath: side sleepers especially, and anyone who has decided an all foam mattress traps too much heat for their taste.
The Build
Ashley's Millennium 2.0 Hybrid (model M313) starts with a stretch knit cover woven with temperature regulating material, meant to keep the sleep surface from holding heat the way a plain foam cover can. Under that sits a gel memory foam layer paired with a body contouring foam layer, the combination that gives the top of the bed its soft, sink in first touch. Below the foam, a NanoCoil unit works alongside individually wrapped coils, so the base of the mattress still breathes and still responds the way a traditional innerspring does, rather than compressing into a single slab. At 14 inches tall, the whole stack has enough depth to sit well on a platform bed, a slatted frame, or an adjustable base without looking undersized.
Feel and Support
Lie down and the first impression is cushioned: the gel memory foam and contouring foam let your shoulders and hips settle in rather than perch on top. What keeps the Millennium 2.0 from feeling like a plain foam bed is what's underneath. Individually wrapped coils move independently of one another, so they follow your body's shape while still pushing back enough to keep your spine level, and the NanoCoil unit adds a finer, more responsive layer of support right under the foam. Together they also help limit how much motion travels across the mattress, useful if you share the bed with a partner who tosses or gets up before you do.
Who It Suits
- Side sleepers who want their shoulders and hips to sink in rather than rest on a firmer surface
- Back sleepers who like a gentle amount of give, not a hard, flat platform
- Hot sleepers who want the cushioning of foam without giving up the airflow a coil base provides
- Couples who want motion isolation without moving to an all foam mattress
Combination sleepers and dedicated stomach sleepers who need firmer, more consistent support underneath may find the plush feel here softer than they're used to. Ask our showroom team about one of our medium or firm hybrid builds instead, no guesswork required.
See It in Person
Specs on a page only tell part of the story with a plush hybrid like this one. Stop by one of our Kentucky showrooms (Lexington, Georgetown, Somerset, London, or Richmond) and lie on the Millennium 2.0 Hybrid in your own sleep position before you decide. That's the clearest way to know how the gel foam and coil combination actually feels under your particular shoulders and hips.
What makes this mattress different
Plush from first touch
Gel memory foam layered over body contouring foam lets your shoulders and hips settle in right away, instead of resting on top of a firmer surface.
NanoCoil plus wrapped coils underneath
A NanoCoil unit works alongside individually wrapped coils, so the base of the bed still flexes and responds the way a traditional innerspring does, rather than compressing into one solid layer.
A cover built to manage heat
The stretch knit cover is woven with temperature regulating material, meant to keep the surface from holding onto body heat the way a plain foam cover can.
Coils that isolate motion
Because the wrapped coils move independently, movement on one side of the mattress is less likely to carry across to a partner on the other side.
A 14 inch profile for standard frames
There is enough depth here to sit well on a platform bed, a slatted frame, or an adjustable base, without the mattress looking undersized for the frame.
Ships compressed, unboxes at home
The mattress compresses for shipping and arrives in a box, so it is straightforward to carry in and set up yourself.
One step up from the all foam Millennium 2.0
If you have felt the Millennium 2.0 Foam 14 Inch and wanted more airflow underneath, the coil base here is the difference.
A taller hybrid sits above it
Want more comfort foam and a slightly taller build using the same coil system idea? The Millennium 2.0 Hybrid 16 Inch is the next step up in the line.
A plush hybrid: soft comfort foam over a real coil base
From the top down, the Millennium 2.0 Hybrid starts with a stretch knit cover woven with temperature regulating material, then a layer of gel memory foam over body contouring foam, the pairing that gives the surface its plush, sink in feel. That comfort stack sits on a NanoCoil unit paired with individually wrapped coils, so the support underneath keeps moving and breathing the way an innerspring does, instead of compressing into a single dense layer the way an all foam mattress can.
That combination is the whole idea behind the hybrid: the foam on top does the cushioning, and the coils underneath do the supporting and the breathing. Because the coils are individually wrapped, they also flex on their own, which is what keeps motion from one side of the bed traveling to the other. At 14 inches total, the build has enough height to work with most platform beds, slatted frames, and adjustable bases.
Want the same plush comfort layer without coils underneath? The Millennium 2.0 Foam 14 Inch runs the same height in an all foam build. Want a taller hybrid in the same family? See the Millennium 2.0 Hybrid 16 Inch.
See the full Sierra Sleep lineup →Built for the side sleeper who wants to sink in
Side sleepers: this is the clearest yes. The plush comfort layers cushion the shoulder and hip, the two pressure points side sleeping loads the most, while the coils keep your spine from sagging out of line.
Back sleepers who like some give: if a hard, flat surface has never felt right under your lower back, the plush top layer with coil support underneath offers cushion without losing the lift.
Hot sleepers moving off all foam: the temperature regulating cover and gel memory foam are built to offset heat retention, and the coil base underneath keeps air moving in a way a solid foam core cannot.
Couples: individually wrapped coils flex on their own, so a partner turning over or getting up early is less likely to travel across the mattress and wake you.
Probably not for you if: you are a committed stomach or combination sleeper who needs firmer, more consistent support underneath. Ask the showroom team to set you up next to one of our medium or firm hybrid builds instead.
Specifications
| Height | 14" |
|---|---|
| Feel | Plush |
| Firmness | Plush, softer than our medium and firm hybrid builds |
| Construction | Stretch knit cover with temperature regulating material over gel memory foam and body contouring foam, a NanoCoil unit, and individually wrapped coils: 14 inches total. |
| Cooling | A gel memory foam comfort layer under a stretch knit cover with temperature regulating material work together to offset the heat that plush foam layers can trap. |
| Motion isolation | Very good: individually wrapped coils and a NanoCoil unit move independently, so movement on one side of the bed is far less likely to carry across to the other. |
Frequently asked questions
How firm is the Sierra Sleep Millennium 2.0 Hybrid 14 Inch?
This is a plush hybrid. The gel memory foam and body contouring foam let your shoulders and hips settle in on contact, while the coils underneath keep you from bottoming out. If you have tried a firmer mattress and found it too hard, this build is meant to feel noticeably softer, without losing support underneath you.
Is this a memory foam mattress or a hybrid?
It is a hybrid. Gel memory foam and body contouring foam make up the comfort layers on top, and a NanoCoil unit paired with individually wrapped coils forms the support base underneath, so it is not a straight foam bed.
Will it sleep hot?
The stretch knit cover is woven with temperature regulating material, and the gel memory foam layer is designed to offset some of the heat retention that plush comfort foam can hold onto. The coil base underneath also allows more airflow than a solid foam core. That said, plush foam-forward beds do run a little warmer than firmer builds; if cooling is your top priority, ask the showroom team to compare this against one of our medium or firm hybrids.
How well does it isolate motion for couples?
Well. The individually wrapped coils and the NanoCoil unit move independently of one another, so movement on one side of the mattress is less likely to carry across and disturb a partner on the other side.
Will it work on an adjustable base?
Yes. At 14 inches, it has enough depth to work well with most standard bed frames, platform beds, and adjustable bases.
What sizes are available?
Twin XL, Full, Queen, King, and California King.
Can I try this mattress before I buy it?
Sierra Sleep beds, including the Millennium 2.0 Hybrid, do not come with an at-home trial period. The showroom is where you try before you buy: come lie on this exact mattress in one of our Kentucky locations (Lexington, Georgetown, Somerset, London, or Richmond) in your own sleep position before you decide.
Can I see this mattress in person near me?
Yes, and with a plush hybrid like this one, lying on it is the best way to decide. Mattress Overstock is a Kentucky-owned company with five showrooms: Lexington, Georgetown, Somerset, London, and Richmond. Everyone on the floor is paid the same regardless of which brand you choose, so the guidance you get is straightforward.
Buy it from people you can actually visit
- Free local delivery To your home across Central & Eastern Kentucky.
- Free setup We place and set up your new bed in the room.
- Free old-mattress haul-away The old one goes out the same day the new one comes in.
Independently owned in Kentucky since 2012. Walk in any day (no appointment) and someone who actually knows the floor will help you find the right fit.
Still deciding?
Try it in person at any Kentucky showroom
Walk into any Mattress Overstock location, lie down, and feel the difference yourself. No appointment, no pressure. Our team has over 100 years of combined mattress experience and we're here to help you find the right fit.
