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King Koil is a mattress brand that was founded in 1898. It started selling innerspring mattresses, but over the years has expanded to foam mattresses as well. You can find King Koil mattresses across the globe in local retailers. Some of their mattress models may be advertised under other names than are found below. Overall, they make comfortable mattresses in a variety of price points, but there were some concerns about durability with some models.
Sleep Science builds a line of latex and memory foam mattresses. Their claim to fame is their 'wedge' technology that provides edge support to every piece of the mattress. Additionally, they are Certipur certified, which means they have low VOC and no formaldehyde in their mattresses. They also use bamboo material in some of their mattresses. Their mattresses are made popular through their relationship with Costco warehouse stores where they are sold at a competitive price vs many of the retail sold mattresses of similar material quality.
Based on our aggregated reviews and our scoring method, we recommend King Koil in this match up!
See Our Full Review of King Koil
King Koil: 8.4/10
Sleep Science: 8.3/10
King Koil: 8.5/10
Sleep Science: 8.4/10
King Koil: 8.2/10
Sleep Science: 8.7/10
No Back Pain:
King Koil: 8.5/10
Sleep Science: 8.3/10
King Koil: $499-$3999
Sleep Science: $399-2499
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Making sense of customer satisfaction can be a great guide in finding yourself the right bed, but it isn't that easy. Overall, these mattresses get mixed feedback. Some reviewers found them to be exactly what they were hoping for, but others had issues with the comfort. Research more below to learn what customers say and how one of these mattresses will react to your body.
Most find these mattresses to be supportive, which means they help keep the back aligned in conjunction with their firmness level. That said, there are a few complaints from reviewers, so make sure to make sure that the materials align with your body type and sleeping position.
Overall, most customers report these mattresses as having satisfactory edge support, which means most don't experience a depression when sitting on the side of the mattress.
Bowling Ball & Density Tests
In bowling ball tests where the firmness is measured across the mattress, these mattresses have good even support throughout the surface. That said, some have had issues with support over the long term, so make sure it works for your body before purchasing.
Reviewers provide mixed ratings about the durability of these mattresses. We all want to find a mattress that will be as cozy now as it was 10 years ago, but unfortunately not all mattresses last for the long term. If you are considering buying a mattress with mixed reviews on durability, do a double-check on the trial and warranty policies and price to make sure that you are comfortable.
There have been diverse feedback from sleepers about these mattresses -- both good and bad. Many report sleeping soundly and feeling cozy in their new mattress, but there were others that didn't feel as positively. Read about the mattress specifics and browse customer reviews in the section below.
Most folks describe these mattresses as doing a good job supporthing their bodies, but others described some discomfort with their mattress choice. For those that have heavier than average body types, read the customer reviews before buying as you'll want to make sure that you are supported well enough for your spine to be aligned.
For those that like to lay down by the side of the mattress, most reviewers describe the mattresses as being supportive on the edges. However, some had complaints so review more if you need edge support for mobility purposes.
Mattresses aren't as durable as they used to be. A mattress that lasts 15 years is a hard thing for find. But, finding a mattress that really is cozy for a long time can save you lots long term. Unfortunately, customers give these mattresses mixed reviews on durability. Many sleepers don't report issues, but others have complaints about durability over a shorter time frame than usual.
This mattress is comfy! It's not too firm and not too soft. I love it! I was a little nervous before I bought it because the price is so low. Once I went in the store and tested it out, I knew I was going to get my monies worth. Granted I've only had it for about a week now, even my boyfriend has confirmed it's super comfortale. Get it while it's on sale.View More Reviews
I bought the twin mattress and much to my dismay there was about a 4 inch gap between the mattress and my bed frame. After measuring the mattress I realized it was only 36 inches wide, not the standard of 39 inches (despite the website listing it as 39 inches wide). I finally got a hold of the manufacturer and they said that their twins are "intended" to be 38 inches wide but that each one can differ by up to two inches. So you're basically left with a mini-twin. I will be returning this.
It's pretty comfy for the price but honestly I could have gotten cheaper at another matress store, definitely shop around more. It's not very thick and the euro top seems like it will be flattened very easily I give it maybe a year before it starts losing its comfort completely
My first set of guests found this to be very comfortable. I slept in the guest room to try it out and found it very comfortable. I am very pleased with this purchase and will purchase future items.
Nice product at the right price. My child needed a mattress for a new college apartment. We saw many options and even ran into a manufacturers rep at the store who helped us with good advice. As usual, the experience was great
love this mattress very comfortable the never disappoint
Great price and such an amazing mattress. The level of comfort is undeniable. I'm very happy with this product and would recommend it in a heartbeat.
This mattress was purchased for a bedroom that is only used for guests and when child is home from college. The mattress is very comfortable and the price is perfect for this situation. We have had it about a week and my kid loves it, it's 12:20 pm now as I write this review and she is still sleeping.
Buying this mattress was an amazing investment. Such a comfortable bed to sleep on and the service and delivery was very prompt and professional.
Very happy with what I bought slept like a baby. The delivery guys came set it up fast. Very happy with the service.
My husband and I are sleeping so much better since purchasing this mattress. It's not too firm or too soft, so you get support without feeling like you're sleeping on a board.
We love our new Mattress! The comfort and quality is unbelievable and for what we paid for it...we just love it!!
I purchased two of these mattress for my boys, without them being there to try them, and they just love it. They said it's so comfortable that it just conforms to their bodies. Mind you my 15 year old is 262lbs and said the bed is like a giant blanket. So hats off for a great product at a reasonable price...
I recently stayed in a bed in a breakfast in Maine--and loved the mattress I slept on. (I've got neck and shoulder issues to the mattress is often crucial.) I found a similar King Koil mattress and Raymour and Flanigan. The price was right; the delivery was prompt. "For this relief much thanks." Happy with my purchse: feels good!
When choosing a bed we needed a firm mattress with back support for me but yet some cushioning for my husband and the King Koil Perfect Response Elite Lakeside Pillowtop was "the perfect" choice. Very pleased with our decision and we even received next day FREE delivery - very nice!
I love my new mattress -and the service that came with it.
The bed is great. It came when they said it would and the sales person was wonderful in working with our family.
Bought this for my guest bedroom and it was given an A plus By my first guest. She couldn't believe it was a firm mattress. Would highly recommend.
WE NEEDED A FIRM MATTRESS AND THIS IS PERFECT! NOT ONLY IS IT EXACTLY WHAT WE WANTED THE INSTALLATION WAS WONDERFUL. WE NEEDED SLATS FOR SUPPORT AND THE DELIVERING TECHS DID IT ALL WITH NO PROBLEM. SALES PERSON WAS WELL INFORMED AND ANSWERED ALL OF OUR QUESTIONS. FLO L
I have a California King Mattress and it is the best.... I was not sure of down sizing to a Queen Mattress, but I must say that it was the best choice I love the way my body rest and the best part is that my husband and I are know closer....
THE MATTRESS AN BOX SPRING I PURCHASED WAS JUST EXCELLENT. ITS MEETS ALL MY STANDARDS FOR COMFORT .THE SALES PEOPLE WERE JUST GREAT HELPING ME FIND THE RIGHT ONE . I HIGHLY RECOMMEND MY CHOICE.AND THE STORE LOCATION ON CROPSEY AVENUE
It's hard to get out of bed after sleeping on this very comfortable mattress. You look forward to relaxing at the end of the day. I like it very much. Keep in mind, coupled with the box spring, it is very high. Can't go wrong with this one, unless you like it extremely firm. It has the right kind of firm but soft too.
Very happy with our purchase! Bed is comfortable. Not too firm, not too soft. Great quality for a great price!
The mattress is very comfortable. It's the best sleep I've had in a long time. It is a 5 star hotel quality mattress. I'm in love. I must stress that the hubby that works at night and have Insomnia also agreed that his sleep has been much better. Thumb's up.
I absolutely love my new bed. Best experience it's comfortable for my back after I come home from work cause I work 19 hours of the day doing labor and I just needed a new way to sleep. This is one of the most comfortable beds I've ever slept in and I highly recommend it to everyone.
The store was great the product was well priced and it was a convenient purchase. Loved the salesmen [Associate name removed].
This mattress has just enough firmness topped with a pillow top that has just enough softness! The price is perfect and the customer service was out of this world. No one trying to force me to the most expensive products in the store.
I am very much enjoying my new mattress. I was afraid it might be too soft but I'm glad I went with the softer mattress over the more firm mattress. While this is soft, it is still very supportive. This mattress is great quality for a good price.
great mattress sleep like a baby love it so much it is great
Best decision i made for my son he loves his new bed. Raymour and flanigan alway have good quality furniture which last a long time. I know when i shop with them im getting good stuff.
I needed a mattress for my fathers spare bedroom so I had a place to sleep when I visited. I didn't want to spend a lot but I wanted something that was nice and comfortable. This mattress is it! I have slept great when visiting him now and the Sales associate Tom P. in Clifton Park listened to my needs and took care of everything! Thank you Tom!
very comfortable but still with support!! Very happy!!
This mattress was purchased for a guest room and has only been slept on once with a report that is was very comfortable. The salesman was very helpful and polite. The delivery team were very helpful and delivered quite timely
I really like this mattress. It's really comfortable and it feels like I'm sleeping on a cloud.
My old mattress was still in good looking shape, but had outlasted the years I needed an extra firm mattress. My new King Koil plush is so comfortable, I sleep right through the night. Both my husband and I are well pleased with this purchase.
Mattress is unbelievably comfortable. My wife and I love it so much.
So far so good! Great price for the quality. I'll write another review after about a month or so
I am so happy with my purchase. I haven't slept this well in a long time. I definitely Recommend this mattress. The salesman was very knowledgeable and he listened to my needs.
I am very happy with my king coil mattress purchase. In the past I have always bought Sealy's. It is very comfortable and I am happy with it. Also the service at the store and the delivery was very good. I am also very happy with the guarantee on the mattress.
Mattress after the first night of sleep had a indentation in it already. Was or is not as comfortable as I expected.
We bought this mattress over a year ago...had no idea that they sold a separate foundation. Spent months replacing the bunky board we got from Crate and Barrell 2 times and dealing with back pain, even called the mattress mfr. The mattress mfr said they recommend their foundation instead of bunky board. Ordering it today, hopefully it will take care of the problem but paying $50 more than if I bought them together from the start. They need to update the description and recommend the foundation if they don't buy it separately OR don't even sell the mattress alone. Description said it needs a 'solid' foundation...what does that even mean? I had a hard time trying to find a bunky board that is solid wood from many retailers. Crate and Barrel's new bunky board is made of compressed cardboard! A painful process, but I like the mattress.View More Reviews
The mattress is definitely on the firm side but we both find it about right. After 11 months, the bed seems to be wearing very well... no signs of change in feel or shape. The adjustable bed is used in zero gravity every night for one of us and not used at all for the other. The adjustable bed works well for back sleepers but not side or stomach sleepers.
This bed is the best we have ever slept on, even 6 years later. We have the queen, and now want a Cali king (we now have a dog sleeping with us), and will be buying another one of these latex matresses from Costco. This one will go into the guest room, and it looks brand new. It has not settled or sagged at all, even though it is used every night, by 2 people. It is NOT hot, either. The memory foam mattress we bought from Costco first, was hot, however. So we returned the memory foam and got this latex mattress. We are so happy!!!
I did what i thought was plenty of research before i bought this bed.. I've waited a full year to try and get used to it, and kept telling myself and my spouse it would get better. Not only was it hard and uncomfortable but, from 3 months on, it had big depression on both sides. It seemed to get worse , not better! The only good thing is i bought it from Costco, so they agreed to take it back, no problem! Yea Costco!!
I bought this bed on July 7, 2016. It was my first Costco online shopping. As in warehouse shopping, the online service was very good. The delivery company did not call me to confirm the delivery time but Joshua and Carlos did great in the delivery of the bed and setting it up. Brandon at the distribution center was excellent. I could test the bed before the purchase. The latex mattress feels cool in summer compared to other types of mattresses. I hope I enjoy my bed for many years to come. I love shopping at Costco!!!
I've purchased 3 of these mattress so far. The first one about 3 years ago, then another one the following year and another one a couple months ago. the first one was in a guest room and the other two were for two of my kids who loved the bed when they slept on it while visiting!
I bought this bed over 2 years ago, maybe 3 years now. My husband was a reluctant buyer, because we are only early 40's :) He thought adjustable was for the nursing home. But he had enjoyed it just as much. It hasn't helped his snoring, but he enjoys the leg elevation and massage features after a tough day or workout, and elevation of his head when congested. I have had a couple of back injuries from car accidents, and sleep considerably better on this bed than ANY OTHER!! We had a memory foam before this. This is NOT memory foam. Memory foam sinks in with your weight, then when you turn over you fall back into the rut you created. Ours was also hot. This foam doesn't radiate heart back at you. I love that! It doesn't sink in. It has great support. It is nice to be able to sleep elevated without getting up in the middle of the night to prop up or go to the recliner. My bed sleeps just like it did almost 3 years ago. No sagging, indentions, or soft spots. It does creak a little when adjusting, nothing a little wd-40 can't fix. The base and massage features still work like a top. No problem! Good buy!
Purchased and received this split King organic mattresses with adjustable bases on April 8th, 2016. What a great product! Both my husband and I absolutely love our mattresses! The adjustable bases fit perfectly inside our existing bed frame, and the mattresses are sooooo very comfortable. I have always been a side sleeper, but no more! I'm able to easily sleep on my back now. Since I am a professional singer, this is a real plus for me. Also, the adjustability allows me to (among other things) raise my head ever so slightly to allow for sinus drainage as well as legs for additional perfectly tweaked comfort. The mattress cover is soft and also feels luxurious. A 3 inch layer of softer 19 ILD natural latex perfectly compliments the firmer 32 ILD layer underneath it to softly cradle with no pressure points yet support my body superbly. Adjustable base works great. Fully articulates for customization. Zero Gravity pre programmed position is heavenly! Don't wait. Buy this now!!! You'll be glad you did! Great price and great product. Thanks Sleep Science - Well done!
We got this bed a couple of months ago. It is very comfortable. Unaware another person is in the same bed. Mattress is fine for us, not too firm and not too soft. No odor.
Delivery company had great personnel.
One side had a control box (located under the bed) that failed in the first few hours. Costco called the company and we had a new one installed by the company in a few days.
I would suggest going to check out Dreamfit mattress covers (they come in twin xl and their kings sheets (2 twin xl bottom sheets with one King top sheet. Their bottom sheets and mattress covers have extra elastic straps to hold the sheets in place. I found these after much research. They stay in place great. Love my bed!!
The mattress delivery was great..even on time. The mattress itself is nice ...no sinking in like foam. Soft and supportive. The adjustable base is great. I do wish the lights on the remotes would come on before you try to poke the right button. Zero gravity setting is awesome!
Its very comfortable. Firm for support but not too firm. My wife & I think it is the best mattress we have slept in. No smell at all.
Disagree with the SUBJECTIVE product details 'Sleep Science comfort scale: medium with a bounce.'
There is missing objective ILD firmness scale info in the product details. For me, 5'3 and less than 120 lb, this is surely a soft latex mattress. In general, The 'soft' designation corresponds to an ILD rating of 19-21. The ILD rating for the medium range is 24-26. After digging yourself, then you find this mattress has ILD 19 on the top 3 inch layer over another 6 inch of 32 ILD.
Best mattress I've ever had
The delivery was early by several days and happened without notice, but luckily we were home to receive the mattress. Unpacking and getting it ready for use was seamless and fast; we didn't have to wait for several hours and slept on the mattress within hours of set-up. So far, the mattress has been comfortable, relieving pressure in all the right places while providing support. I wake without the aches and pains I had come to assume were "normal" as I grow older. I am optimistic that it will continue to be as comfortable for many years to come.
We found this mattress to be extremely firm. We bought a softer topper to help but unfortunately it did not. We have purchased 5 other foam mattresses for ourselves and family members and had been very pleased. This one was just too firm.
Mattress is so firm and comfortable!
We picked this up because I have a bulging disc in my back and even though our other mattress was only 3 years old, it wasn't cutting it. I Love This Bed!!! We've only had a couple of months but so far so good. It's firm the way I need it and supportive. I'm a big guy 6'2 270lbs and it's great for me.
It’s a very good mattress and my mom loves sleeping on it. The mattress is true to the firmness.
Love it feels great for my back and gives plenty of support. Even better you don’t feel any movement when there’s someone next to you.
My husband and I both love this bed! It keeps us from getting overheated (a big issue of mine) and is the perfect firmness. This is our favorite bed after having two other gel cooling foam mattresses that have also been purchased recently. Actually, this is our favorite bed we've ever had and we are both 60.
Very happy with this purchase. Mattress is super comfortable and the firmness just right for both wife and I. (Of course firmness and comfort are subjective and very individual.) The adjustable functions work great and motors are pretty quiet. This was a major factor in our decision as my wife just now had shoulder surgery and sleeping in a reclined position is needed. Packaging and assembly are quality although it would be recommended for 2 people to carry base pieces and mattresses from delivery location to bedroom. Assembly video very helpful. Time will be the teller for durability, but very happy with the purchase and first impression.
the bed is comfortable but its been only 1 week since I have been using it.
Love my new Sleep Science split king bed and adjustable frame. I have only slept in in the last 4 nights so this is an early evaluation. We had a temperpudic for the past several years but this has surpassed that at more than half the cost. So far this bed is my favorite plays to be.
Don't waste your time and money . I had this mattress for more then a month. An every morning i woke up with sore Back .I am been using memory foam mattress for more then 10 years and I never had such a horrible mattress for the price i paid . I am glade i got it from Costco so I could easily return it ..
Good mattress that was delivered one month late. Came rolled up. Have to let it rest for 3-4 days to self inflate and acquire firmness. Since its brand new cannot say how long it will remain firm
Great bed! Sleeping great & elevate when needed without disturbing spouse.
Terrible mattress. Got it delivered after a month after it’s shipped (which is after a week after I ordered). Mattress has some stains on the bottom. Couldn’t spend another month and half without a mattress so opened it. Both Costco and sleep science have deceived me to the core and lost all the respect and trust I had in both these brands. It’s not firm at all, people who love plush would rate this below plush rating. I’ve no energy and time now to deal with the customer service at Costco which discontinued email and chat supports. Staying on phone with them for hours and getting mediocre resolution isn’t worth.
Sleeping was too warm and too firm
So far so good. Hoping for a number of years of the same. Attractive and comfortable.
Very good quality; perfect firmness and it’s a good looking matress.
Mattress was advertised as extra firm and we have found after 2 weeks of sleeping on it the areas where we sleep are already getting soft. Not sure if we will be able to keep it.
My new wife has complained about how much I enjoy sleeping (i.e. I occasionally snore) which apparently keeps her awake. I had a 10 year old sleep number bed that she despised sleeping on because she prefers a firm mattress (firm as in she'd be more comfortable sleeping on the floor than a soft bed) and I was more flexible. She'd mostly started sleeping in the spare bedroom every night because of these two factors when I saw this bed go on sale around memorial day. I figured why not give it a shot and if it didn't work out, we could always return it. Well right from the very first night she noticed a difference where I slept in the zzzz setting and didn't make a sound. That kept up for weeks until we took a small trip and stayed in a hotel room and the snoring returned. We both totally looked forward to coming back to our bed. I've been sleeping comfortably and so had she. Now we can both sleep together in peace.
Super comfortable. Easy to assemble with two people. We love the adjustable settings. Zero gravity is divine!
This is the most firming bed i ever experienced. May be too firm.
Excellent bed great support
It IS a from mattress of very good quality. The massage and adjustability of this bed are great. I’m hoping it softens some, I’ve had it for one month.
After 1 month we are very happy with the purchase. Firm but very comfortable mattress is exactly as described. Motorized stands work very well and seem to be high quality. The price was less than half of what we saw in bedding stores. We should have purchased sooner. My only comment would be that a set up and mattress removal service should be offered.
started great...slowly sank and now i feel like i am sleeping in a pothole. it went from good to worst really quick. not happy with this purchase but happy with costco policy. they are awesome.
I had the bed for 1 1/2 months, it served whatever expectation I have for this bed that's why we bought it. Me and my husband likes it a lot.
Sleep in this mattresses for one month. Good quality but just too firm for me.