What’s The Number 1 Best Firm Mattress?

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What’s The Number 1 Best Firm Mattress? It’s Idle Sleep (Here’s Why)

A really firm mattress is the only thing you might want or need to help you get the best sleep. You’ve been hunting around looking for one, and sure there are some great options, but you’re getting frustrated! How are you meant to choose what’s the number 1 best firm mattress with so many out there? I’m here to tell you about the mattress with the firmest rating of them all. Not only that, but it’s got some pretty great features that set it apart as an all-round excellent mattress. Let me introduce you to the Idle Sleep Hybrid Mattress.

What's The Number 1 Best Firm Mattress - Cover Image

What’s Inside This Article:

Who Needs A Firm Mattress?

Why Idle Sleep Is The Best (Some Of The Reasons May Surprise You)

Idle Sleep Mattress Construction

Pros And Cons

Reviews From Real Customers

Codes To Get The Latest Deals From Idle Sleep

Who Needs A Firm Mattress

There are lots of situations a firm mattress is what you need. These include:

  • You like to sleep on your stomach. You need to make sure your lower back is properly supported, because your hips can tilt into a mattress that is not firm enough. You also need a mattress with good cooling function.
  • You weigh 250 lb or more. You need a firm mattress to ensure you’re getting the support you deserve. If your mattress is too soft, the comfort layers won’t do anything to support you and you’ll feel uncomfortable and maybe even sore.
  • You just like the feel of a really firm mattress!

Here’s the kicker: Depending on you and your circumstances, what is “firm” is totally different. For a light person who sleeps on their side but really likes a firm mattress, “firm” is going to mean a mattress with a totally different feel than what the quarterback who sleeps on their stomach needs. So how can there possibly be one answer to “what’s the number 1 best firm mattress?”

What if I told you there was a mattress that could cater to both? I’ll explain in the next section.

Why The Idle Sleep Hybrid Mattress Is The Best Firm Mattress

Idle Animated Image

There are 7 reasons why the Idle Sleep Hybrid Mattress is the best firm mattress, for everyone. It’s not surprising that the hybrid is the clear best seller of the Idle Sleep range (and they make some other really great mattresses)

  1. It has the firmest firm side of any “mattress in a box”. With a firmness rating of 8.5 – 9 out of 10 on the mattress firmness scale it’s about as firm as you can expect to find. Anywhere.
  2. This mattress is flippable, and you can have a different firmness on each side. This is what makes the Idle Sleep Hybrid suitable for everyone looking for their perfect firm mattress. You can choose to buy your Idle Hybrid with two really firm sides, two medium sides, or one of each so you can try out both in the one mattress! The medium side is rated around 6.5 out of 10, which is a medium firm. This will feel comfortable for lighter people or side sleepers seeking a firm mattress.
  3. If something in your life changes and you need a mattress with a different firmness for whatever reason, you’ll be totally future proofed with a double sided mattress.
  4.  It is better value for money. Because the mattress is flippable, it has double the amount of comfort foams of other mattresses in boxes around the same price point. It also means it’s going to be more durable because you can flip the mattress and spread the wear on the comfort foams around.
  5.  It has a hybrid construction, which ensures better air flow around the mattress than an all foam mattress. This is great news for people who sleep hot, stomach sleepers, and heavier people.
  6. The responsive and carefully chosen foams mean this bed has a great balance of pressure relief and bounce.
  7. Idle Sleep offer the longest sleep trial I’ve ever seen: 18 months. Yes, you can try this mattress in the comfort of your own home for a year and a half before you need to commit to it. That is absolutely huge and not offered by anyone else, except their new sister brand, Haven. Oh, and it has a lifetime warranty too.

Idle Sleep is a mattress I keep coming back to talking about. It’s pretty hard to ignore! It’s made many of my “best” lists, including my best mattress recommendations for heavy sleepers (read here) and stomach sleepers (read here).

Idle Sleep Mattress Construction

What's The Number 1 Best Firm Mattress? cross section

The total mattress height is a luxurious 14 inches (many others are 10 – 12). Your Idle Sleep Mattress is made in USA, either in Illinois or South Carolina.


Thermacool temperature regulating fabric.

There is a 1 inch layer of foam quilted into the cover: this is Idle Contouring Foam, designed to start giving you pressure relief

Comfort Layer: 

There are two foam layers here. The first is a 2 inch layer of buoyancy foam. This is a foam that’s designed to react quickly to your body pressure, offering pressure relief but also bounce and holds you up on the mattress rather than giving you the feel of sinking in. It’s an open cell foam, which means air can flow through it

Underneath the buoyancy foam is one inch of transition foam. This layer provides further pressure relief and acts as a cushion between the buoyancy foam and the pocket coils below. This foam has convolutions in it rather than being flat, to further help with air flow.

Support Core:

Idle uses the Quantum Coils Support System.  This is durable network of individually wrapped pocket coils, which are designed to give targeted support while minimizing motion transfer. These coils are enforced at the edges of the mattress to ensure you get great edge support.  Here’s the coil count for each model:

Twin: 756 support coils
Twin XL: 772 support coils
Full: 1016 support coils
Queen: 1,130 support coils
King: 1,414 support coils
Cal. King: 1,384 support coils

Comfort Layer: 

Under the coils, you’ll find the exact same comfort layers repeated on the other side of your mattress. You can choose to have the same firmness on both sides, or have two options in one mattress.

Another thing to note: this mattress has strong fabric handles sewn into its sides. This is really helpful if you want to flip it, because it is a rather large mattress. I have seen one person flip it on their own, and it looks easy enough but the handles really are critical to that.

Pros And Cons


  • Two Firmness Options Make It Suitable For Anyone Looking For A Firm Mattress
  • Flippable  (Increased Durability, Increased Choice Of Firmness)
  • Longest Sleep Trial And Lifetime Warranty
  • Good Temperature Regulation
  • Good Combination Of Bounce And Pressure Relief


  • Like All Hybrid Mattresses, Not As Great At Motion Isolation As All Foam
  • Heavier Than A One Sided Mattress

Reviews From Real Customers

I scrolled quite far through the reviews on Idle, and struggled to find anything negative. I also looked at other places around the internet where people go to complain about or discuss mattresses, and also came up blank. Overall, people are really happy with their Idle Hybrid. They particularly like that it’s flippable and many also commented that the free pillows were cooling and comfortable.

Idle Hybrid Mattress Reviews From Real Customers

Don’t Miss Idle Sleep’s Great Sales

Like most mattress in a box companies, never pay full price for your Idle mattress! There is always a special of some kind running. The current sale is the best of the 4th of July sales I’ve seen (most others are up to 20% off, and wouldn’t dream of offering an adjustable base).

These two offers are available until July 8 so get in quick:

Free Adjustable Base with purchase of any mattress (up to an $649 value): code 4JULYADJUST

30% off entire website (any purchase): code 4JULY30

Idle Sleep Hybrid Mattress

From $1041 - But Never Pay Full Price

Quality Of Materials


Value For Money


Customer Service



  • Excellent Value For Money
  • Two Firmness Options
  • Longest Trial And Warranty Of Any Mattress


  • Heavier Than Other Mattresses In Boxes


Emily Johnstone

Emily is the creator and owner of bestmattressforyou.com. Emily's scientific background gives her an analytical, critical, and discerning eye to bring unbiased, thorough, and helpful content to the site. Your good sleep is her top priority. Find out more about Emily and bestmattressforyou.com here.