Sleep Number M-7 VS. I-8 – Which Model Is Right For You?

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Deciding between Sleep Number’s M-7 and I-8 mattresses will inevitably come down to whether or not people like sleeping on memory foam. Those who love it will most likely prefer the softness of the M-7 and those who like pillow top mattresses will love the I-8.

We’ve put together a guide that compiles all the features of each mattress to help people decide which model may be best for them.

Key Similarities

  • A variety of standard sizes – including FlexTop
  • Individual or dual air chamber options with DualAir™ adjustability
  • Sleep IQ Technology is included in both
  • Both mattresses are $3,499.98 for a Queen

Both come with this optional feature:
FlexFit™ Adjustable Bases

Key Differences


  • 12” mattress profile
  • Unique soft flat cover in a grey color – no pillow top (mattress top)
  • 2” foam layer underneath air chamber(s)
  • 4” gel memory foam layer with CoolFit technology above air chamber(s)
  • Mattress fabric is made with a rayon/polyester blend fabric that is designed to be soft and breathable


  • 13” mattress profile
  • Duvet pillow top that includes 2” of Hypersoft Quilting Foam for a plush surface and Outlast temperature balancing technology to minimize temperature swings
  • 1” foam base pad underneath the air chamber(s)
  • 3” of PlushFit foam that is specifically designed for Sleep Number to help relieve pressure
  • 7 zones specifically designed to contour to the head, shoulders, lower back, hips, knees, lower legs, and feet
  • Mattress fabric is made with a polyester/polypropylene blend fabric that is designed to be soft and breathable.


Read our all-encompassing Sleep Number review

What I Found From Several Live Chat Sessions

After speaking with Sleep Number Customer Service representatives, I learned about a few extra details and clarifications that may help people decide between the M-7 or the I-8 mattress.

  • Mattress Tops: Since the M-7 is all about memory foam, the mattress tops on these two will vary greatly. The M-7 is soft but flatter (non-pillow top) and grey in color. People will most likely sink into this mattress more than the I-8 which is plush and has quilting foam sewn into the mattress top (as opposed to memory foam).
  • Firmness: According to the Customer Service representatives that I talked to, it’s hard to compare the firmness of these two mattresses. While the air chamber(s) will help dictate the firmness in each mattress, the layers of gel comfort foam and memory foam will add different feels and conform to the body differently. One representative did tell me that the I-8 was probably a little softer because of the pillow top mattress surface.
  • Cooling Technology: The M-7 and the I-8 both offer ways to keep people cool at night. For the M-7, it’s the CoolFit memory foam with gel technology that should help people sleep through the night. On the I-8 it is Outlast Technology material in the surface of the mattress that is supposed to absorb body heat and redistribute it throughout the night to keep people comfortable while they sleep.

Which Should People Pick?

M-7 if…

  • People Like Memory Foam. There is 4” of gel memory foam above the air chamber(s) in the M-7 mattress. One Customer Service representative told me that the M-7 is usually only recommended for people who know they like to sleep on memory foam and who are looking to make it adjustable – by adding one of Sleep Number’s FlexFit adjustable bases.

Read our full Sleep Number M-7 review

I-8 if…

  • People Want A Mattress With A Pillow Top. The I-8 has a super comfortable mattress top. It’s got a woven Duvet pillow-top that includes 2” of Hypersoft Quilting Foam for a plush surface. Since the M-7 features memory foam, the top of that mattress is still soft but flatter.
  • People Want Contoured Pressure Relief. The 3” foam comfort layer in the I-8 mattress is designed to contour specifically to seven areas of the body to relieve pressure: head, shoulders, lower back, hips, knees, lower legs, and feet.

Read our full Sleep Number I-8 review

Both if…

  • Someone Is A Hot Sleeper. Both mattresses include cooling technology. The M-7 has cooling gel technology in the 4” foam layer but the I-8 features Outlast technology on the mattress surface that is designed to pull moisture away from you at night and redistribute throughout the night.
  • People Want Sleep IQ Technology Included. While you can always purchase the technology for an additional cost, the sleep tracking device is already included in the price of the M-7 and I-8 mattresses.

My Personal Opinion

Both mattresses cost $3,499 for a Queen. Since price is not a consideration when choosing between these two mattresses, it will really all come down to personal preference.

The Sleep Number Customer Service representatives told me that they really only recommend the M-7 mattress to those who know they love memory foam mattresses and want to add an adjustable base to the mix.

Since I’m not the biggest fan of memory foam and prefer a plush mattress top to a flat one, I would definitely go with the I-8 mattress over the M-7. Both mattresses offer cooling features and Sleep IQ Technology, so it all just comes down to personal preference.

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Katie Golde

Katie manages the day to day operations of the Mattress Clarity news site and reviews sleep products in addition to writing and editing sleep news. She hails from Austin, where she lives with her growing family. She is a Certified Sleep Science Coach and has a master’s degree in Journalism from Northwestern University and has a background in health and science content. Her work can be found in print and online publications like Discover Magazine, USA Today and The Huffington Post.