In short: The Beautyrest Harmony Lux Diamond mattress is a high-end hybrid bed designed for soft mattress aficionados. It comes in ultra-plush, plush, and medium firmnesses that work well for lightweight people and side sleepers. The generous foam layers and pocketed coils support a healthy spine while cushioning pressure points.

Who It’s Best For

Harmony Lux Diamond is best for:	Harmony Lux Diamond may not be best for:
Side sleepers Back sleepers Lightweight people People who like to be “hugged” by their mattress Hot sleepers Couples and those who co-sleep	Plus-size people Stomach sleepers People who prefer a firm mattress

The Best of This Mattress

Simmons Beautyrest is known for their high-end hybrid mattresses. The Harmony Lux Diamond mattress is one of the most luxurious hybrid mattresses around. With thick layers of plush foam and multiple firmness options, this is one of the best hybrid beds for people who find most mattresses too firm. 

In this review, we’re going to delve into everything you need to know to decide if this is your dream mattress. This includes its construction, firmness, pros and cons, and much more. 

A lot to love:

• It is one of the best mattresses for side sleepers and lightweight people thanks to thick layers of pressure-relieving memory foam.
• It comes in multiple firmnesses that range from ultra-plush to medium. This means every soft mattress lover can find a firmness that fits their preferences.
• The T2 Pocketed Coil support system is made from a generous 9.5” of pocketed coils that deliver targeted support. This means excellent spinal alignment.
• It offers incredible motion isolation thanks to thick foam layers and individually-encased coils.
• Beautyrest mattresses come with complimentary white glove delivery, so someone else will set up your new mattress for you.

Mattress Lab Testing Scores

We haven’t had the chance to get our hands on the Beautyrest Harmony Lux Diamond mattress. When we bring this bed into the Mattress Advisor lab, we’ll evaluate it on 14 factors that include performance, function, and customer experience. 

Learn more about Our Review Process.

Mattress Advisor Test	Score (Out of 10)
Shipping	8
Trial Period	9
Return Policy	9
Warranty	9
Set-Up	10
Motion Transfer	6.5
Edge Support	9
Pressure Relief	9
Spine Alignment	9
Responsiveness	7.5
Cooling	9
Durability	9
Customer Service	6.5
Social Impact	7

⭐Total Score for the Beautyrest Harmony Lux Diamond Mattress: 8.5/10 ⭐

The Pros and the Cons

✅ Pros

• Pressure Relief: This is one of the most pressure-relieving hybrid mattresses on the market. The feel is one of sleeping on clouds.
• Spine Alignment: Pocketed coils deliver balanced support that conforms to your body shape. The result is good posture while you’re sleeping. 
• Cooling: Beautyrest incorporates cooling technology throughout the Harmony Lux Diamond mattress. As a result, it’s a good bed for people who sleep hot.  
• Durability: The Harmony Lux Diamond mattress has thick, supportive coils and high-density foams that make it more durable than the average mattress.
• Edge Support: This mattress does an excellent job of holding you up when sitting or lying on the side, so much so that you may think you’re in the middle of the bed.

❌ Cons

• Responsiveness: The Beautyrest Harmony Lux Diamond Series mattress doesn’t have much bounce to it, meaning it may be difficult to switch positions at night.
• Customer Service Availability: You can only get in touch with Beautyrest using email, which means there’s no way to ensure immediate help. 
• Off-Gassing: With generous memory foam layers, there’s likely to be a slight scent for the first few days. But don’t worry, this odor fades quickly. 
• Not for Heavier Folks: The Harmony Lux Diamond is simply too soft for most people who weigh more than 230 lbs. 

Pressure Relief

The Beautyrest Harmony Lux Diamond mattress is the thickest hybrid mattress that we’ve seen. The Classic Top measures 14.25”–14.5” and the Pillow Top 17.25”–17.5”. This is compared to the typical 10” mattress. With this much foam, you can be confident that the Diamond mattress has sufficient cushion to relieve pressure at pressure points.  

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Motion Isolation

If you spend your nights with a fidgety partner, child, or furry family memory, your best mattress is one that minimizes the movement that you feel. Despite the 8” of motion-dampening foam and pocketed coils, the Beautyrest Harmony Lux Diamond doesn’t minimize motion transfer as well as most all-foam mattresses. For a better motion isolating mattress, consider the Layla mattress.

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Responsiveness

Combination sleepers get the best sleep on mattresses that are easy to move around on. You don’t want to feel like you’ve sunk into quicksand when switching from one position to the next. Responsiveness is the term that describes how well a mattress adapts to movements. 

The Harmony Lux Diamond mattress has an incredibly lofty layer of bouncy innerspring coils that supports ease-of-movement. However, with thick foam layers on top, it’s not quite as easy to move around on the Lux Diamond as it is on innerspring mattresses or some hybrid beds. If you toss and turn a lot, you may want to look for a hybrid with thinner comfort layers, like the Casper Original.

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Firmness Scores

The Beautyrest Harmony Lux mattress is much softer than your average medium-firm mattress. With multiple Diamond mattresses, there are different firmnesses to choose from. Here’s a breakdown of how soft each mattress is on a 1-10 firmness scale. The higher the number, the firmer the mattress. 

• Classic Top Medium: Medium (5)
• Classic Top Plush: Medium-soft (3.5)
• Pillow Top Medium: Medium-soft (4)
• Pillow Top Ultra-Plush: Soft (3) 

There are two groups of people that tend to prefer soft mattresses like the Lux Diamond. The first are side sleepers. When you sleep on your side, you need a mattress that cradles the hips and shoulders, avoiding excess pressure. The second is lightweight people. When you weigh less than 130 pounds, mattresses feel firmer. A mattress surface must be soft enough to allow lightweight people to sink in a bit for optimal comfort.

 

Will It Support Your Sleeping Position?

The Harmony Lux Diamond is much softer than the average mattress. With generous foam layers, it’s designed primarily for side sleepers and anyone who desires extra cushion. Most stomach sleepers do better on a firmer mattress. Back sleepers who prefer a soft bed are also a good fit. Combination sleepers who spend most of their time on their back or side are likely to enjoy the Lux Diamond.

Temperature Regulation

The Harmony Lux Diamond Series has Beautyrest’s InfiniCool cooling technology. A cool-to-the-touch mattress cover, gel-infused foam, and breathable foams and innerspring coils create a cool sleeping environment that can help hot sleepers stay cool.  

Weight Capacity

Because the Harmony Lux Diamond mattress is soft with generous foam layers, it’s going to be best for people who weigh less than 230 pounds. Heavier people are likely to experience excess sagging at their hips, potentially causing lower back pain.  

Bed Frame Compatibility

The Harmony Lux Mattress requires a sturdy base that’s in good condition. This includes a box spring, platform bed, or a slatted base with slats no more than 2” apart. This bed is compatible with adjustable bases. 

A Look Inside

The Harmony Lux Diamond Series consists of four mattresses that contain robust pocketed coils and numerous memory foam layers. The series is broken down into two categories: Classic Top and Pillow Top mattresses. The Classic Top comes in a medium and plush firmness and the Pillow Top in a medium and ultra-plush feel. 

We’ve broken down the various layers that are found in each Diamond mattress. The thickness and materials vary by both firmness and whether it’s a Classic Top or Pillow Top.

Beautyrest Harmony Lux Diamond Classic Top

The Harmony Lux Diamond Classic Top model comes in a medium or plush feel. There are slight differences in the foam layers within. The medium Classic Top is 14.75” deep and the plush is 15”. Take a look at what’s inside. 

1. Seaqual Sustainable Fabric Cover: A cover made using unique fabric technology that converts plastic water bottles recovered from the ocean. The resulting material is soft and durable. 
2. SurfaceTouch Gel Memory Foam: Soft comfort foam that hugs the body’s curves. Gel moves heat away from the sleep surface. 
3. Gel Touch Foam (Plush Only): A soft layer of cooling gel memory foam cushions pressure points for a cloud-like feel. 
4. RightTemp Wave Foam: A proprietary polyfoam that brings pressure relief and additional cooling technology in the form of conductive carbon fibers. 
5. Firm Comfort Foam (Medium Only): A layer of firm foam supports proper body alignment and limits surface sagging. 
6. Micro Diamond Memory Foam: A high-density memory foam brings close contouring while cooling Micro Diamond Technology supports a cool sleep environment. 
7. Medium Comfort Foam (Medium Only): A final layer of foam that’s firm enough that you won’t feel the innerspring coils but soft enough that you don’t have to sacrifice comfort. 
8. Gel Touch Foam (Plush Only): Another soft layer of cooling memory foam for plush softness. 
9. T2 Pocketed Coils: A support system with a pocketed coil design. These coils move independently so you experience customized comfort. 

Beautyrest Harmony Lux Diamond Pillow Top

The Harmony Lux Diamond Pillow Top mattresses have a close hugging feel. The ultra-plush Pillow Top mattress is 17.5” thick and the medium Pillow Top is 17.25”. While many of the foams and the coil support system are the same, there are also numerous differences. Let’s take a look inside.

1. Seaqual Sustainable Fabric Cover: The same durable, eco-friendly cover as found in the Classic Top version. 
2. SurfaceTouch Gel Memory Foam: An identical cooling, plush top layer as in the Classic Top mattresses. 
3. Gel Touch Foam (Ultra-Plush Only): The same incredibly soft cooling foam as found in the plush Classic Top bed. 
4. RightTemp Wave Foam: The same pressure-relieving, cooling proprietary foam is found in the entire Diamond Series. 
5. Plush Comfort Foam (Medium Only): The medium pillow top mattress has plush comfort foam for enhanced pressure relief.  
6. AirCool HD Memory Foam (Ultra-Plush Only): A layer of cooling, conforming memory foam designed to keep the ultra-plush mattress as cool as the other models. 
7. Dynamic Response Memory Foam (Medium Only): A firmer, more responsive foam is used in the pillow top mattress transition layer to make it easier to move around. 
8. Micro Diamond Memory Foam: The same cooling high-density foam as in the original version.
9. Gel Touch Foam (Ultra-Plush Only): Another layer of ultra-soft foam for a cuddly sleeping experience. 
10. Medium Comfort Foam (Medium Only): The same durable yet conforming foam as found in the medium Classic Top mattress. 
11. T2 Pocketed Coils: The same individually-encased coils for balanced support and comfort.

Mattress Size and Cost

Size	Dimensions	Weight	Price*
Twin	38” x 75” x 14.75”/17.5”	62–66 lbs.	$1,999
Twin XL	38” x 80” x 14.75”/17.5”	66–105 lbs.	$2,049
Full	53” x 75” x 14.75”/17.5”	87–134 lbs.	$2,119
Queen	60” x 80” x 14.75”/17.5”	111–161 lbs.	$2,119
King	76” x 80” x 14.75”/17.5”	135–205 lbs.	$2,699
Cal King	72” x 84” x 14.75”/17.5”	142–211 lbs.	$2,699

*Prices do not reflect exclusive offers or discounts. Click below to see the best price for the Beautyrest Harmony Lux Diamond mattress.

Unboxing and Set-up

Unlike most online mattress purchases, your new Beautyrest Harmony Lux Diamond mattress isn’t going to be delivered in a box. Instead, a representative will deliver it to you, set it up, and even remove your old mattress. There may be a slight odor for a few days as the memory foam layers air out. 

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Shopping With Beautyrest

Here’s what you can expect when you buy the Harmony Lux Diamond mattress through Beautyrest’s online site. 

Policy	Details
Delivery	Free white glove delivery
Trial Period	100-night trial
Warranty	10-year warranty
Return Policy	Free returns during the trial period
Financing	Available through Affirm

 

Free Shipping

The Beautyrest mattress is shipped for free within the continental United States. Beautyrest doesn’t ship to Alaska or Hawaii. Not only is shipping free, but it comes with complimentary white glove delivery. This means you won’t have to set up your new mattress—someone else will do it for you! Old mattress removal is also included. 

Most mattresses arrive in 5–14 business days.  

Try It Out for 100 Nights

You have 100 nights from the day you receive your new mattress to decide if you want to keep it. This 100-night trial is standard in the online mattress world. What makes this trial stand out is that there’s no waiting period, so you can return the mattress at any time during those 100 days.  

The Warranty

The Harmony Lux Diamond mattress comes with a 10-year warranty. This warranty covers errors in workmanship or material defects, such as indentations greater than 1.5”. To initiate a warranty claim, you may call 877-399-9397 or email customerassistance@simmons.com.

The Customer Service Team

To get in touch with Beautyrest, send them an email at support@beautyrest.com. They’re open on weekdays from 9 a.m. to 5 p.m. PST. During those hours, you’ll likely receive a response within an hour or two as we did. Unlike the majority of other mattress companies, there is not a phone number or live chat feature for immediate assistance.  

Beautyrest Return Policy

If you discover that the Harmony Lux Diamond mattress isn’t all that you’d hoped it would be, contact Beautyrest before your 100-night trial expires at support@beautyrest.com. They will have someone come to your door to pick up and recycle your mattress. After that’s been completed and verified, Beautyrest will issue a refund.  

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Should You Buy It?

The Beautyrest Harmony Lux Diamond mattress is an excellent choice for luxury mattress shoppers who prefer a soft feel. At up to 17.5” thick, we have yet to come across a hybrid bed with more generous foam layers. This plush, pressure-relieving foam delivers a deep body-hugging feel, much like you’d expect from an all-foam mattress. 

With three firmness levels that range from soft to medium, this is a great pick for side sleepers and back sleepers who like a softer feel. We also love its soft surface for lightweight sleepers, no matter their sleeping position. 

Unlike many luxuriant soft mattresses, the Harmony Lux Diamond does a good job at keeping sleepers cool. Cooling innovations are found throughout the mattress so that you don’t wake up hot and sweaty. We also love how well the thick layers of foam minimize motion transfer, helping couples sleep together without waking one another up. 

What really sets this mattress apart—its sumptuous softness—makes it not the best mattress for all sleepers. Many people require a firmer mattress. People who weigh over 230 pounds and stomach sleepers should look for a more supportive bed. One of our top firm mattress picks is the Alexander Signature Series mattress.

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Harmony Lux vs. Other Mattresses

The Beautyrest Harmony Lux Diamond vs Other Hybrid Mattresses

The Beautyrest Harmony Lux Diamond is a luxury mattress with an extravagantly plush feel. The ultra-plush, plush, and medium models all boast generous layers of pressure-relieving foam, making the Diamond one of the best hybrid mattresses for lightweight people and side sleepers.  

The Beautyrest Harmony Lux Diamond vs Other Beautyrest Mattresses

The Beautyrest Harmony Lux Diamond is Beautyrest’s best mattress for people looking for an opulently plush mattress. Let’s see how it compares to Beautyrest’s other mattresses.  

The Beautyrest Harmony Lux Diamond vs The Beautyrest Black  

The Beautyrest Black is Beautyrest’s premium mattress. As such, it’s more expensive than the Harmony Lux Diamond. Both are high-end hybrid beds that are thick, pressure-relieving, and supportive. 

When it comes to the sleeping experience, the Lux Diamond has a softer, more enveloping sleeping surface. The Black has a more balanced feel that falls between sleeping “on” and “in” the mattress. This difference makes the Diamond better for lightweight sleepers and the Black a better fit for bigger bodies. 

Learn more in our Beautyrest Black mattress review. 

The Beautyrest Harmony Lux Diamond vs the Beautyrest Harmony Lux Carbon

The Beautyrest Harmony Lux Carbon Series is a slightly less posh version of the Lux Diamond Series. Both hybrid mattress lines come in a Classic Top or Pillow Top, with the Lux Diamond boasting thicker foam layers. This gives the Lux Diamond a softer, more conforming feel. While both come in medium and plush versions, the Carbon comes in extra-firm and the Diamond in ultra-plush.   

To see if the Lux Carbon is the mattress for you, read our Beautyrest Harmony Lux Carbon mattress review. 

The Beautyrest Harmony Lux Diamond vs the Beautyrest Black Hybrid

The Beautyrest Black Hybrid and Harmony Lux Diamond are hybrid mattresses with similar firmnesses. They both come in ultra-plush, plush, and medium, making them best for side sleepers and people who prefer a soft bed. 

The Beautyrest Black Hybrid is slightly more expensive because it contains Beautyrest’s cutting edge technology. These innovations make the Black Hybrid cooler and more responsive. However, the Lux Diamond has a slightly deeper hugging feel, great for people who like an extremely plush mattress.   

Find out more about the Beautyrest Black Hybrid. 

The Beautyrest Harmony Lux Diamond vs the Beautyrest Harmony

The Beautyrest Harmony is the most affordable Beautyrest mattress. While it too is a high-quality hybrid, it comes in different firmnesses than the Harmony Lux Diamond. The Harmony comes in a plush, medium, and extra-firm mattress. The Harmony Lux Diamond is available in ultra-plush, plush, and medium. This means the Harmony is better for people who like a firm feel and need additional support, and the Lux Diamond for ultra-soft mattress fans.

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Also Available for Purchase

• Flat Foundation
• Advanced Motion Base

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