Memory Foam Mattress Help

Discussions General Mattresses Questions
7

Hey Phoenix,

I definitely understand why the ILD and density of the support layers is so important now. I am also starting to realize the importance of working with a sales representative who is knowledgeable and has my best interests in mind.

I just spoke with a Spa Sensations (Zinus Inc) representative and he told me the following about their 12" Theratouch Mattress:

3" 3lbs Memory Foam Layer - 8~9 ILD

3" Super Soft Pressure Relieving Foam w Ventilation - 15ILD

6" HD PU foam base - 25ILD

That is definitely different information about the memory foam layer (3lbs vs. 5lbs) than what is advertised on other sites. It seems like they miss the mark as well in regards to ILD and they didn’t even give me the density of the support layers when asked.

Right now it is looking like I will either go to a local store, purchase the Aerus from Walmart, or possibly online with My Luxury Mattress. Of the online outlets you listed earlier (select foam, foam source, and my luxury mattress) my luxury mattress looked the best. The only worry I have is they state the customer is responsible for repacking the mattress properly (boxed and bagging) to be shipped. That seems like it would be an ordeal since they are usually vacuum packed. I sent them an email to get the specifics on this.

It is too bad there aren’t more companies online who offer a quality 4-5lb memory foam in this price range with an extensive trial period and cost free return. If you know of any other local stores besides sleepez or furniture row please let me know.

I sent an information request to FXI to find out the density and ILD of the polyfoam used in the support layers under the memory foam of the Aerus. I’ll be sure to let you know what I find out.

Lastly, you mentioned proper testing of a mattress for spinal alignment and pressure relief, do you have any specifics on that?

Thank you again!

8

Hi Jmoss,

Thank you so much for the information. I was skeptical of the density information about the Spa Sensations as it didn’t seem to be in line with other Zinus brands and I am thankful that you took the time to do the research.

I am somewhat adverse to ordering a memory foam mattress online without a great return policy for several reasons.

Memory foam itself has a basic “set” of chemicals and method of manufacturing that is used but there are hundreds of variations between manufacturers and even the same foam manufacturer will often have dozens of variants and custom formulations which can change the recovery time, the breathability and heat retention, heat sensitivity, and many other characteristics of their memory foam, even when similar densities are compared. The support layers and the ticking/quilting can also make a huge difference in how the memory foam “performs”. This means that memory foam comparisons between different manufacturers, even of the same density, is not as easy to “translate” as latex (which has much more similarity in its characteristics between different manufacturers than memory foam) or even polyfoam.

So in many cases … buying a “standardized” memory foam mattress online regardless of the density or quality of the memory foam itself can be a roll of the dice. Very few people who are looking for a memory foam mattress truly realize how different they can be and how many factors can change the feel and performance of the mattress they are considering. Since memory foam, in general, is pressure relieving … the biggest variables are in the support, feel, and heat retention of the memory foam mattress and of course in its durability (and in the case of unknown foams … harmful chemicals and VOC emissions).

The thickness of the memory foam layer and the type of layers under it can play a major role in alignment regardless of the quality of the memory foam itself. Memory foam in very low densities are also not as “gradual” in their response and so can be much firmer when cold and then melt more easily when warmed up and become too “soft” and a person may “go through” the memory foam onto the firmer layers underneath which can cause pressure issues in spite of the memory foam. Of course, they are also not as durable. Lower density memory foams may also be more breathable because the internal structure is not as dense and “insulating”. There are also many other factors involved with heat retention of a memory foam, however.

Memory foam and viscoelastic materials also have a characteristic called “creep” which means that over time … they become softer (lose some of their resistance to pressure) in addition to the variables of heat, pressure, and humidity. This means that someone who may be in alignment at the start of the night may sink deeper over the course of the night and lose alignment … even if the heat and humidity don’t change.

For all these reasons … and more … I believe it is much more “accurate” to purchase a memory foam mattress through personal testing rather than buying online … at least without a great return policy. If someone can test a memory foam mattress locally with a known type of foam and then that same construction and foam is available online … then, of course, the risk of getting it wrong is much lower. Overall local manufacturers or smaller sleep shops are usually a much better way to go when that is possible and the value is similar.

I did talk with Rocky Mountain Mattress yesterday about their memory foam mattresses. They sell Bayer memory foam on their main pages (which is a large foam manufacturer but not listed on Certi-Pur) but they also have a selection of Foamex memory foam (which he actually prefers as well). The Foamex are layered DIY constructions and the support layers can be customized much like many latex DIY mattresses that some of the members here sell. They may be worth considering. Their Foamex mattresses are here http://www.rockymountainmattress.com/specials-c-28.html . They also have some good youtube short clips showing the different responses of different memory foams.

FWIW … Sensus is a slower recovery foam than Aerus (both are Foamex) and less breathable but “denser feeling” or “firmer” than the Aerus although I use firm here only relative to other memory foams as no memory foam is really firm unless it is cold.

I will list more as I come across them or do a little more research on many I already know about for those who may be looking to buy memory foam online in spite of the “risk” of doing so.

Information about the basic functions of a mattress (pressure relief and spinal alignment) is here Five steps to your perfect mattress - Support and Alignment - The Mattress Underground. General information about testing for pressure relief and alignment (and the other steps to finding your perfect mattress) is here Five steps to your perfect mattress - Overview - The Mattress Underground and more details about pressure relief testing are here Five steps to your perfect mattress - Pressure Relief - The Mattress Underground and spinal alignment testing here Five steps to your perfect mattress - Support and Alignment - The Mattress Underground

Phoenix

9

Hi Phoenix,

I’ve been wanting to reply to your post earlier, but I’m still waiting on Foamex/FXI for a response on the density/IFD of their 7" Intelliform layer underneath the memory foam. They replied back, but gave me the test data on their open flame evaluation instead. I contacted the Stork Materials (company who does the testing) evaluation manager to see what he found. I’ll be sure to keep you updated.

I’ve looked at Rocky Mountain Mattress previously, but the one turnoff I had with them is they charge you on returning the product. I’m definitely not a fan of that!

http://www.rockymountainmattress.com/company/returns.php

  1. The customer is responsible for return shipping, including any and all shipping fees. Please contact us in advance if you plan on returning your mattress, and we will provide complete return instructions and the correct shipping address.

Thanks again for all of your advice and I’m currently reading your articles on how to properly test a mattress for pressure relief and alignment.

John

10

Hi JMoss,

While I know that there is no specific information about the ILD of the poly under the memory foam, It would be in the range of 28 - 35 and likely closer to 28-32. This would be in the medium to medium - firm range. If they put firmer foam under 3" of 4 lb memory foam … a mattress with this type of layering construction and materials would be too firm for most people and not suitable for “mass marketing” as the transition between the memory foam and the firmer poly under it would be too great. The polyfoam (Intelliform) is also made by Foamex.

I also understand the hesitation with return shipping charges. There are many online outlets however that charge much more to return a mattress because they will charge a return fee or restocking fee and also charge you for the original shipping cost in addition to the return shipping cost if a mattress is returned. These types of return fees (original shipping plus restocking fee plus return shipping) can make the cost of returning a low cost mattress impractical which is the reason the fee structure is set up the way it is and why they can often charge less for their mattresses (knowing they have greatly reduced the practical ability to return it). I personally believe that return fees that only charge for the cost of return shipping are much more reasonable and an “acceptable risk” … especially if some preliminary research and testing can give you an idea that the mattress you are buying is at least close to what you would need and the chance of a return is lower. The greater the total cost of returning a mattress … the more important it is to have a clear idea that it will be suitable.

One of the things I did like about Rocky Mountain Foamex mattresses (not the Bayer ones) is that the layers can be re-arranged (both the core layers and the memory foam layers if there is more than one) which can change the feel and performance of the mattress which in turn significantly reduces the chances that it will need to be returned (especially if your testing indicates that it was at least close to what you need in the first place). This “at home” customization can certainly play a big role in “getting it right” without the need to exchange the mattress.

The tradeoff with outlets like this is you gain the ability to tailor the mattress to your needs because of their greater selection and choices (rather than the all or nothing approach of an outlet like Sams Club, Walmart, or Costco) but there is a minimal shipping charge to return it (it can usually be returned UPS which is much less than truck freight but repacking the mattress can be somewhat difficult).

Outlets like My Luxury mattress will not charge for returns at all (even return shipping which is quite rare outside of box stores) but this cost of business (there will be more returns) would also be built in to their pricing structure.

When purchasing online … the costs involved in “getting it wrong” need of course to be balanced against the choices offered and how likely it is that your choices may or may not be correct for your needs.

Phoenix

11

Hi Phoenix,

Sorry for the delay and thanks again for the education. I definitely understand the pros/cons now of purchasing online and if they offer free returns how they build that into their price model.

I’m still waiting on a response by Foamex for the information on their support layer in the Aerus mattress available at Walmart/Sam’s Club. I like that I can return the mattress to either store, it’s 4lb density for the top layer, CertiPur-US certified, and American made.

I really like the option as well of trying the different layers of foam offered by Rocky Mountain Mattress. Being able to interchange the core and memory foam layers is a nice feature. The mattress with the Aerus foam looks like the choice for me. The price is a bit higher than I would like, but it may be worth it.

Is there any others besides Rocky Mountain Mattress that you like and offer multiple layers of quality foam? I think I’m going to pull the trigger this weekend. Thanks again!

John

12

Hi jmoss,

I did a quick calculation based on layer thickness and product weights on the intelliform support core and it worked out to about 1.8 lb density. This would be typical for a mattress in this budget range and I would consider this to be acceptable as a support layer. The ILD though isn’t listed although it would be safe to assume that it was between about 28 and 35 based on the fact that these mattresses are geared towards “averages” and either less or more than this would make them either too soft or too firm for too many people.

Of the few online sources that I listed earlier in this thread …, some offer interchangeable support layers and/or memory foam layers to various degrees.

The first group are Trusted members of the site which means that I think highly of them and believe that they compete well with the best in the industry in terms of their quality, value, service, and transparency. They also provide a 5% or more discount and/or a bedding bonus on any mattress purchase (unless there is a special discount or sale which is greater than the members discount and can’t be “stacked”) when you mention that you are a forum member here.

Christeli are a factory direct manufacturer (over 80 years) specializing in memory foam mattresses, with two of their higher end models featuring latex cores. They have some innovative designs and use good quality materials (including 5 and 6 lb memory foam, 2 lb polyfoam, and latex). and holds one of the best standards in the industry for quality/value, knowledge, transparency, and service. Their 3 collections and most of their 9 mattress models have various adjustability options to cover a large range of sleeping needs and preferences.

Comfort Sleep Systems They carry memory foam it in various densities and will tend towards the more durable 1.8 lb and higher polyfoam in the poly up to 2.6. The Interchange system is a premium mattress for those who want to customize.

Luxi Sleep carries two foam mattresses: a basic and a highly adjustable mattress: The Luxi 3-in-1 Adjustable Mattress (Memory Foam Quilted & Rayon Cover)
Interchangeable Comfort and Support Modules for best-needed configuration and Luxi One Mattress. See mattress specs here.

Mattress To Go excellent retailer in Shelby Township, MI one having one of the highest levels of expertise in componentry and matching customers with the right mattress carrying only high-quality lines (including Memory Foam beds) at an excellent price point.

Magic Sleeper A consumer-friendly mattress store in Pottstown, PA that carries various brands as well as their own make.

Memory Foam Comfort Canadian online retailer that sells a range of memory foam mattresses that use good quality materials including 4 and 5 lb memory foam, Energia 3 lb HR polyfoam, and high quality/density base foam. They are good quality and value and provide good guidance over the phone. Their memory foam and polyfoam is also CertiPur certified.

Nest Bedding (Albany & Berkeley, Chicago, Costa Mesa, Denver, Minneapolis, New York, Palo Alto, Phoenix, San Francisco, Santa Monica, Seattle, Studio City). They are knowledgeable, experienced, and transparent and carry several memory foam mattresses that they sell locally and online including traditional memory foam mattresses and memory foam/pocket coil hybrids (including two-sided) that all use high-quality materials. Joe the owner left a larger manufacturer that had a somewhat exaggerated focus on “green” mattresses to form his own company because he wanted to “do it right”. They offer several Discount codes here: to consumers coming from TMU (they will also match any other larger discounts for the members here).

Oklahoma Mattress Company is a great manufacturer in Oklahoma carrying may types of mattresses.

Parklane Mattresses in OR or WA states local manufacturer focusing on high-quality and wide range mattresses and foundations.

Sedona Sleepis a sister company to Arizona Premium Mattress. This is also one of the new breed of “simplified choice mattresses” and is a two-piece component system that is somewhat unique because it includes a separate finished “base mattress” that is made from 7" of 1.9 lb polyfoam which can be used by itself as a low-cost medium firm mattress. It can also be used underneath an existing topper if you already have a topper and the mattress underneath it has developed soft spots or is sagging and needs to be replaced.

Sleep Boutique Canadian local manufacturer in Calgary, AB who has modular mattresses to allow for changing components if the customer needs and preferences change over time.

https://www.sleepez.com/ The top 3" layer of their latex component mattresses can be ordered with 5.5 lb Sensus memory foam instead of latex for those who prefer the feel of sleeping on a memory foam comfort layer. The support layers are latex and can be both re-arranged and exchanged for different firmness levels. Of course, the price here reflects that the base layers are latex rather than polyfoam and the memory foam is a slightly higher density of Sensus. Side by side split layering is also available.

Texas Mattress Makers

Some of the Non-members that I believe also offer some good quality and value memory foam mattresses include …

http://www.selectabed.com/ They are a factory direct manufacturer. I have talked with Dr. Rick Swartzburg at length who designed these mattresses and I think highly of his designs which are CertiPur certified. They also make a more premium line of Tempflow mattresses here which use a very high-quality memory foam which is custom poured to their specs which they can also customize (and are Greenguard Gold certified). They can help you compare their mattresses to other mattress lines (such as Tempurpedic) as well. See post #9 here.

https://www.foamorder.com/memory.php They are also a factory direct manufacturer that use a high quality 5.3 lb memory foam and an exceptionally high-quality base layer (either 2.5 lbs or 3.0 lb polyfoam which is close to the highest density polyfoam base layer I have seen in a memory foam mattress). They also have an edge support feature for those who sleep with more of their weight concentrated on the very outside edge of their mattress or who often sit on the very outside edge of their mattress. Also, CertiPur certified.

http://lakemattressandfurniture.com/ They are a factory direct manufacturer that have a range of US made memory foam mattresses that use 4 lb memory foam and up to 2.4 lb base foam which are good quality and have some good value and they are fully transparent about their materials as well. They use all US made foams.

http://www.sleepwarehouse.com/memory-foam-mattress.aspx Available with either 3" of 4 lb Aerus or 5 lb Sensus with interchangeable support layers. There is a choice of ILD in the interchangeable base layers. Also CertiPur certified.

http://www.plushbeds.com/memory-foam-mattresses.html They are a factory direct manufacturer and make several memory foam mattresses that use 4 lb gel memory foam along with 2.5 lb polyfoam and latex (in some of their models). Their memory foam and polyfoam is also CertiPUR certified.

http://www.selectfoam.com/ They used to be a member of this site but their membership has been terminated. See the warning posted in this topic.

All of these represent good value and options IMO. As I am able to talk with more that I believe offer good quality memory foam options, I will add to this list.

For those who are also interested in non memory foam options as well there is a list of the members of this site which specialize in online sales in post #21 here who all compete well with the best in the industry in terms of their quality, service, and value as well as the help and guidance they offer to their customers.

Phoenix

13

Hi Phoenix,

Well, I purchased the Aerus mattress and have been sleeping on it for a couple of days now. So far, so good and I believe the ILD is around 35 so it is on the firmer side, which is probably better for me since I am a stomach sleeper. Thank you again for all of your help. Your advice and insight has been invaluable in my selection of a memory foam mattress. I’ll be sure to keep you updated if anything changes, but I feel good about the durability and quality of the mattress I purchased. Thank you!

John

14

Hi John,

Thanks for the kind words and congratulations on your new mattress. Keep an eye out in the first few weeks for any possible back issues from stomach sleeping on memory foam but if you are OK after that you will likely be fine :slight_smile:

Enjoy

Phoenix

15

Wow, this is some incredible information you’ve compiled here phoenix! It really helps me to narrow down my decision.

Now there’s one thing I’m wondering about still - how much difference will the height of the mattress make? I’m going to be using the mattress in my RV and there’s just barely enough room for a 10", but 8" (or maybe even 9") would be more ideal. Will a couple inches in the support layer make much of a difference? I’m trying to weigh the pros & cons…

Also, I see many of them offer the coolmax cover to reduce heat retention. Do you have any insight on how well it actually works?

16

Hi pnuker,

There is a more information in post #14 here about thicker mattresses vs thinner mattresses but the essence is that if a mattress is thicker it will compress more gradually which may have some advantages for heavier people who sleep in multiple sleeping positions. It would also depend to some degree on the specifics of the layers that are chosen.

8" - 9" of latex is generally easily enough for most people to “design in” a suitable balance of pressure relief on top and support/alignment underneath unless the circumstances or individual preferences indicated otherwise.

Layering choices would make more difference than the extra couple of inches by itself (even though all else being equal they would make some difference even if many people may not feel it) but the extra couple of inches may allow for options that are more flexible for unusual circumstances or just for people who could tell the difference and preferred it.

A coolmax cover (or any cooling technology) can certainly be part of the “sleeping cool” puzzle in combination with all the many other factors in a mattress that work together (or in some cases against each other) to regulate humidity, ventilation, and temperature. Each layer that you use including the layers, types of material, and components in the mattress, the ticking/quilting that you use, the mattress protector that you use, and the sheets and bedding can either add to or detract from the sleeping temperature of a mattress. There is more about sleeping cool in post #2 here.

Phoenix

17

Hi there Phoenix,
Been looking at some of the online names you mentioned and found your comment to someone about stomach sleepers having trouble with memory foam. Can you please elaborate on that a bit? I am one and I’m planning to purchase memory foam! Oh No! :open_mouth:

Debbie K.

18

Hi DebbieK,

Stomach sleepers don’t have trouble with memory foam as a material so much as they may have trouble with thicker layers of memory foam (or thicker upper layers of any soft foam).

The reason for this is that stomach sleeping has a risk of sleeping in a swayback position if the comfort layers are too thick which can cause discomfort or pain from misalignment.

Memory foam also has another property called “creep” which is common to all viscoelastic materials. This means that with constant pressure over the course of time (such as the hours you are asleep) the foam “relaxes” (independent of the typical softening of memory foam with temperature and humidity) and can allow your heavier parts to sink in deeper over the course of the night so you may go to bed in good alignment but them your heavier pelvis/hips can sink in too far and you may wake up with stiffness, discomfort, or pain. Faster response materials such as polyfoam or latex don’t have this same degree of creep so if you are in good alignment when you go to bed you will still be in good alignment in the morning.

In general it’s a good idea to use thinner layers of any soft foam for pressure relief (but especially for memory foam) if you are a stomach sleeper so that you are closer to the support layers of the mattress which can “stop” your heavier parts from sinking down too far (keep your spine in better alignment). There’s more about some of the needs of different sleeping positions in this article.

If you are a combination sleeper then the thinnest firmest comfort layers that are “just enough” for good pressure relief and no more will usually be best for alignment when you sleep on your stomach.

Phoenix

19

Phoenix,

I would like to add one piece of information though. I called foamorder.com (based in SF) because I am in the Bay Area and I believe their foam is made in China with the final assembly here in SF. I would have second thought on that brand unless I mistakenly confused that with another brand (I have been studying/verifying several high density brands and it’s been very overwhelming).

It also has pretty poor yelp reviews. Not saying Yelp is all that reliable but I would take precaution.

Apologize in advance if my information is incorrect. I don’t want to mislead but just want to share this. I had originally considered it since it’s in my backyard but now I have eliminated this brand.

20

Hi 1ch1ban,

Yes … their “standard” memory foam is made in China and in this case it’s not CertiPur certified so I personally wouldn’t consider it … even though there are some Chinese memory foams that are CertiPur certified and are good quality and value.

Their latex is good quality … although it’s not the lowest cost latex option.

Phoenix

21

Phoenix,

I just joined The Mattress Underground and am currently looking at Restava mattresses. You have a very helpful and informative site here.

I came across this post and wanted to know if you made a typo when you stated:

“www.restava.com/ they make gel memory foam mattresses that use 4.2 lb co-mixed gel memory foam, 5.3 lb memory foam, and 2.5 lb base foam which are all good quality materials. Their customer service has also improved since they started and they are also now CertiPur certified so I would not include them among the better quality/value choices”.

Your last sentence states that you “would NOT include them among the better quality/value choices.” Is this what you meant?

Thank you.

22

Hi Rockethead26,

What a difference a letter can make!

As you probably guessed I meant “NOW” when I added them to the list. The list only includes some of the better options (not the hundreds I wouldn’t include) but it certainly didn’t read very well and I’ve corrected it in the original post as well.

Thanks for catching the typo :slight_smile:

Phoenix

23

Hi Phoenix,

Thanks for your great site and the obviously large amounts of time you put into it. Appreciate your list of memory foam vendors as that is the kind of bed I am looking to buy. I have low back issues in the form of ruptured/bulging discs and am a back sleeper. My wife is a back and side sleeper and in our initial tests… we like the feel of the cloud luxe by Tempurpedic (though I worry if it is perhaps too soft/deep to offer adequate back support). Wondering if you could recommend any other dealers here in the San Francisco, CA area?

Thanks much!

24

Hi hwuya,

The better options and possibilities I’m aware of in the San Francisco region are listed in post #2 here.

Phoenix

25

Thanks for the link to the store list… I thought I searched for San Francisco but must have missed it. I checked out a local vendor, FoamOrder, since they are local. They are great but we found that the 5.3lb comfort layer didn’t produce the “ahh” factor that we felt from the 4lb memory comfort level on the Tempurpedic Cloud Luxe mattress. I didn’t see a lot of other local options for memory foam on your list that looked great so I think we are going to pursue online order options with a 4lb memory foam comfort layer on bed models trying to emulate the Cloud Luxe.

After surfing around a lot on your great site (thanks again) I have narrowed down the list to the usual suspects below and was wondering if you could perhaps provide some additional thoughts on some of the differentiating characteristics of the following models:

Cirrus Luxe by Select Foam, Cool Luxe by BrooklynBedding and Tri-Pedic Diamond by Selectabed (would dig into Resteva’s Ivory Gel or Rocky Mountain Mattress models if needed but trying to reduce options at this point!).

Specific pluses and minuses and questions for the various models are as follows:

Cirrus Luxe –

Soy Memory foam – Selectfoam replaces some petroleum by using 20-30% soybean product. This supposedly reduces the odor from off gassing. A local retailer here noted that they had bad experiences when they were evaluating soy based memory foam from a compression perspective. Have you heard of any challenges to the product durability, off-gassing advantages or any thing else regarding soy based memory foam ?

Memory foam is manufactured in the US but isn’t certified (though in a 9/14/11post you mentioned that they were… did they lose it?) . I wasn’t too concerned about this but you note that certification as a general guideline requirement in some of your previous posts. I’m assuming since this is a member manufacturer… you must have gotten over the potential risks (VOC, emmisions, etc.) this lack of certification?

Base foam is HD not HR – beneath the 2.5" 4lb comfort memory foam layer and the 2" 7.2 (used to be 8.0lb) support memory foam layer is a HD 2.5lb (32 ILD) soy poly layer. Given that this model is a bit more expensive than the other models, do you think this significant enough to lean toward the Tri-Pedic Diamond which does have HR poly in its base layer?

Tri-Pedic Diamond –

Optional Air Flow system – Given that heat rises, I don’t quite get how the hot air exits here but more potential airflow seems a good thing. Any thoughts on if this affects durability of the foam since it is in some ways it now seems less structurally sound and less dense?

Flat shipping of mattress – Selectabed claims that rolling/vacuum bagging high quality foam in order to ship isn’t good for high quality materials. Any thoughts on how concerned you would be about other vendors using vacuum/compression shipping methods?

Memory foam density - This model uses 5 lb memory foam instead of 7.2 lb memory foam in the support layer. Seems like higher density would be better but SelectFoam shifted from 8lb to 7.2lb noting that it was too firm (and, perhaps more likely, do to supply availability). Surprisingly, FoamOrder, noted that they tried 8lb memory foam and had greater durability complaints with no perceived benefit. Again, any color on 5 vs 7lb density. I know you say any thing over 5 is good but wouldn’t more be better?

Cool-Luxe – Seems decent and it is cheaper (which is good) but if the above characteristics are are beneficial, we would be inclined to give those a try instead.

All the above offer good return policies (though you have to pay shipping on the Tri-Pedic on both directions) but hoping any inputs you could provide will steer me to a decision that will help me avoid a need for returns.

Thanks so much!

26

Hi hwuya,

You are asking a some good questions that go to the “heart” of some of the current marketing (and in some cases misinformation) in the industry.

The properties of memory foam are determined by its chemical formulation more than its density. While it’s often true that higher density memory foams are more temperature sensitive and slower responding and firmer than lower density memory foams, there are no “rules” about this. Many people prefer the typically softer “feel” of lower density memory foams even though there would be a durability tradeoff. There is more about the many different properties of different memory foams in post #9 here and post #8 here.

You can see some comments about “so called” soy based or “plant based” foams in post #2 here. While it’s a step in the right direction … it’s mostly about “green marketing” (and in many cases greenwashing) because in most cases the plant oil derived polyols are a chemical derivative of the plant oil and are far from “natural” plant oils (outside of castor based polyols which require much less chemical modification than other plant oils to be used as a polyol because of the hydrogen bonds). I would treat them as close equivalents to regular petrochemical polyfoam and memory foam in terms of durability.

In terms of smell it would depend on the specific formulation of the foam and some plant based foams can have a worse odor than some foams that only use petrochemicals depending on the formulation or the treatment (or in some cases the rancidity) of the plant oil and on how well or completely it reacts in the foam formulation and manufacturing process. One of the limitations of the amount of plant based polyols that can be used in a foam is the odor (although a bigger limitation is the effect on durability and performance with higher plant oil concentrations). Plant based polyols also vary in smell depending on the type of plant oil and the type of chemical modification that it goes through (just like there is a wide range of smell in petrochemical foams) and castor oil is the only one that can be used closer to its more natural form. I would treat odor on a “foam by foam” basis rather than a “category by category” or “generic” basis.

The smell of a polyurethane materials (polyfoam and memory foam) is also a completely separate issue from the safety of the foam because some chemicals that can be smelled are not particularly harmful and some that can’t be smelled are more harmful so the only objective way I know to assess the harmful substances in a foam material that can leach out or the amount of harmful VOC’s that are released is through actual testing and certification. Even with certification … some people will still be sensitive to the smell of some particular formulations of foam or be more sensitive to some of the VOC’s than the limit values … and there can also be differences in the same foam from batch to batch depending on how the formula is adjusted or cured with changing conditions or on how well it is aired out after it is made.

Almost all the memory foam manufactured in the US is made by one of the foam manufacturers that are CertiPur certified*. Individual mattress manufacturers can also choose to become CertiPur certified (even though the foams they use are already certified) but many mattress manufacturers choose not to do this because of the cost involved (although the list is growing*). If the foam is made in the US then the odds are high that it is either CertiPur certified or would pass the CertiPur certification process if it was tested. I would insist on CertiPur certification though if the foam is made offshore because they may be using chemicals or production methods that aren’t used in the US and regulations may be different. Basically the replacement of petrochemical polyols is mainly about using more renewable sources, building a marketing story that attracts “green consumers”, and also is part of a general conservation trend of avoiding petrochemicals which can be more volatile in terms of pricing and less about smell or durability.

ADMIN NOTE: *Removed 404 link|Archived Footprint 1:certipur.us/pages/for-industry/find-a-foam-supplier/|Archived Footprint 2:certipur.us/pages/for-consumers/find-products/ & replaced with latest CertiPUR list

The deeper support layers of a mattress are not generally the weak link of a mattress and once you are past about 2.2 lbs density with conventional or HD foams there would be little difference in durability anyway because higher density than this is usually accomplished with fillers. Foams that are 2.5 lb density or higher are not necessarily HR polyfoams (or cold cured foams) unless they also have a compression modulus of 2.4 or higher and 60% resiliency or higher. True HR polyfoam on the other hand does have higher polymer densities but it’s biggest advantage is that is has better performance and is more “latex like” in its properties. There would be little “practical” difference in terms of durability in a support core compared to say a 2.2 lb conventional foam but depending on the construction it could make a bigger difference in the feel and performance of the mattress for some people. Whether it was important or not would depend on whether it was an improvement in terms of PPP. In most memory foam mattresses (again depending on the specific design) most of what you “feel” would be the memory foam layers.

Gel foams on the other hand may have less smell because the gel materials themselves are non toxic and have little offgassing or smell and anecdotally they appear to have less odor issues “in general” than non gel foams. The gel also has other effects on the foams but there is also a great deal of misinformation in the market about gel materials in general.

Post #2 here and the posts it links and leads to to can help “unravel” some of the information about gel materials (or gel memory foams) on the market because there are many different versions of gel memory foams and many “marketing stories” that may not all be accurate.

As a very broad overview … gel will have some smaller or temporary effect on cooling (depending on the percentage and type of gel), it can have a positive effect on the tendency of memory foam to become softer over the course of the night with increasing temperature or with continuous pressure, and it will generally have a “neutral” effect on foam durability overall although some of the earlier gel formulations with larger particles that can migrate out of the foam more easily can have a more negative effect on memory foam durability and some of the liquid gel additions can have a more positive effect on foam durability because there are no particles and it can form its own polymer matrix when the foam is manufactured. While I haven’t seen any specific testing information about VOC’s in gel foams on a foam by foam basis … it would also make sense that it would have a positive effect on VOC’s and smell because the gel itself is non toxic.

Memory foam heats up throughout the material and having good airflow that has an “escape route” to the outside environment can help with removing any heated air. The movement of the body would provide a “pumping” action to help the air escape from the sides of the vents. Without a method of allowing the air to escape under a memory foam layer (either through the material itself or through vents) there would be nowhere for the warmer air to go. This type of system (punched holes with a ventilation system underneath it) is more effective than simply punching the memory foam full of holes but where the air can’t escape to the same degree (except through the material itself). While the holes may have a small effect on durability “in theory”, I also don’t believe it would have any significant effect on durability in real life because the foam structure is the same (just like the pincores in latex don’t affect durability) and there isn’t enough material removed to make a significant difference.

There are also other methods of reducing the temperature of memory foam that are discussed in post #6 here and there is more about the many factors that can affect the sleeping temperature of a mattress or sleeping system as a whole in post #2 here.

Higher density memory foam will be more durable than lower density until you reach about 6 lbs or so and after that the increasing durability effects of higher density are greatly diminished. As you mentioned … in some higher density memory foam formulations can also result in a foam with reduced durability because of the greater difficulties involved in production or curing of the foam. Basically I would say that “more is better” up to about 6 lbs and beyond that it’s more about the “feel” and performance of the memory foam than it is about durability.

Short term compression of foam materials generally won’t harm them (with a few exceptions of “stiffer” or firmer foam) but if the foam is compressed for more than a few weeks … especially in a humid environment … then it can affect the durability of the foam. Using pressure compression to roll pack a mattress is generally less harmful than vacuum compression to the cell structure of a foam (particularly if the vacuum compression extracts all the air) and in both cases it’s a matter of time and degree. Most foam manufacturers will provide good information to their customers (the mattress manufacturers) about which of their foams is more suitable for compression and which ones may not do as well.

Hope this can help you make a choice or make more meaningful comparisons between some “good vs good” options :).

Phoenix