We recently bought the IKEA Utaker stackable twin bed frame for the guest bedroom, with the intention that it be a kids bed in 2-3 years time. Reading TMU - we thought it would be a good idea to get a latex/hybrid latex medium/firm twin bed, 6"-8", for the stackable bed hoping it will be comfortable for guest adults (150lbs-250lbs) and toddlers (3-5yrs old). However, weāre hoping each twin mattress be less than $400 if feasible (after TMU discounts). Weāve been sleeping on our 6 year old random Sealy coil mattress that cost $600 and it feels strange to spend so much more on a guest/childrenās mattress.
I think 6āā of soft 28ild latex would be very reasonable for adults, although the comfort level will depend on their weight. Medium or firm will probably be too firm for adults. Here is another possible option for $349.
Dear Ken, can you please explain why adults should sleep on firmer latex? For the last 1.5 months, we were sleeping on a 3āā latex topper at 30ild (on foam). I found it way too firm (200lb) while my wife found it soft (130lb). It agrees with latex response curve. It feels soft at low compression and quickly firms up as with compression. So for a heavier person like me it becomes like a rock. I actually folded it in half and slept on a 6āā layer of 30ild. It was better but still had an uncomfortable shoulder pressure with a cover on top. This observation seems to agree with Spindle mattress configurations. They call 20ild latex āmediumā and 30ild latex āfirmā, and their soft, medium, and firm configurations all have 20ild layer on top. Only extra-firm has 30ild on top. And this is for 9āā mattress which should feel softer than 6āā. At 6āā at 20ild would be firmer than what they call āmediumā. This agrees with my experience, so I donāt understand why some people on this site keep saying that adults need to sleep on firmer latex?
One possible explanation is that you use Talalay and they use Dunlop? In that case why would ild be rated the same while actual firmness is so different?
Thatās exactly why, dunlop gets firmer as it compresses where Talalay is consistent. Iām not saying an adult canāt sleep on soft Iām just saying in general a medium would be better without knowing weights and sleeping style.
Here is a response curve of Dunlop vs Talalay. Dunlop is softer until about 30-35% compression. I cannot imagine children compressing even soft one by more than 35%. For adults, yes, Dunlop firms up much faster around 50%, but I donāt know how heavy one has to be to compress 6 inch latex by 40%.
Let me dispel the myth that Talalay is Softer than Dunlop.
The indenter used in ILD testing has the surface area of 50 square inches. And it needs the force of 200,000 Newton to compress 4āā talalay in the above graph to 40%. That means that 200 lb person would need to apply all his/her weight over the surface area of 2.36 square feet to really notice the difference between Talalay vs Dunlop. Average body surface area of 200 lb person is about 21 square feet. So one needs to apply all the weight on about 11% of your body. Even sleeping on the side, this is impossible.
Talalay sellers always say that it is softer than Dunlop, while Dunlop sellers say this is not true: https://sleeponlatex.com/blogs/news/7845413-dunlop-vs-talalay-latex-foam . According to physics, Dunlop sellers are correct. There might be a difference in feel, but not firmness. In fact, according to the above graphs (which comes from Talalay seller KTT Enterprises) dunlop will be about the same or slightly softer for most people.
As a seller of both Talalay and dunlop latex for over 22 years I can say that I disagree with HappyCat as do the customers who come in to our showroom where they can try both Talalay and Dunlop of equal ILDās side by side. Dunlop feels firmer than the equivalent Talalay and thatās verified by our customers.
It might āfeelā firmer but it is not firmer in the sense of force/pressure at 25% compression. And up to 40% they are about the same. If you stand on latex with your feet or, perhaps, sit on it then it will be firmer I agree. Ken, I do not doubt your expertise, so I would be happy to learn from you in what sense they are softer or firmer. Is it texture or something else?
I was scanning through your multiple postings across many forum topics and had to quickly step in as some of your postings can more confuse than help clarify questions of topic initiating poster.
You have brought up several issues in different topics not the least of which is the danger of reading too much into online reviews of any type (see post #13 here)
While education and research is key in finding a good product that matches all your personal criteria Iād caution against making such general blanket statements as there is really no āstandardā type of feel or āstandardā perception of softness /firmness of Dunlop vs Talalay latex. Aside from any scientific data or experiments, generally applying such āstandardsā can be not only confusing to the average consumer but challenging even to those with many years of experience in mattress design mainly because it all plays out in a larger context of how all layers work together and also personal needs and preferences for an individual sleeper. There are too many interacting variables of different ILDās, different layer thicknesses combinations and firmness levels, latex types, and different ticking/quilting combinations that can have a big effect on the mattress and can have a very wide range of different feels and interact very differently with different people (BMI, where the weight is carried, sleeping stile, body surface in contact with the mattressā¦ etc). This is one of the main reasons weāve started the āAsk an Expertā program on our forum. The many years of experience with materials, and product designs but most of all ā¦ how different body types and individual sleeping styles respond to the multiple variables involved in mattress construction is why I so often recommend to rely on the advice of a manufacturer (that has your best interests at heart) as they are much more familiar with their own mattress/topper designs and materials than anyone else (including me or other forum moderators) and they can use the information provided about body type, sleeping positions, preferences, history on different mattresses, and the results of any local testing to make suggestions based on the āaveragesā of other similar customers.
There is a technical spec for foam which is called compression modulus which is the ratio between the force needed to compress a foam to 25% and the force needed to compress the same layer to 65% of itās thickness. 65% is exactly 2.6 times 25% which means that a completely linear compression rate would have a compression modulus of 2.6. This is approximately the compression modulus of Talalay latex.
For the hybrid versions, you mentionā¦ it generally known by experts that springs have a similar measurement called spring rate. Because they are linear ā¦ a single spring which has the shape of a cylinder and has even turns will have an equivalent spring rate of 2.6 (because it would be compressing 2.6 times as far). This means that the compression modulus of Talalay and the spring rate of a cylindrical spring would be similar. Dunlop has a higher compression modulus so it would get firmer faster than this same type of spring ā¦ but this is where the similarities end. Most springs have a softer section and a firmer section (which can be achieved with different shapes such as thinner and thicker diameters in parts of the spring or different gauge springs on top of each other and in other ways as well). This means that this type of spring would have multiple spring rates. You can see some graphs of the response of variable rate springs here and you can also see a typical compression curve of Talalay latex here directly from TGās older article about it.
If you would like to dive a little deeper into technicalities, it would be best to move this discussion to a different more relevant topic so as to keep the original Posterās more focused on the topic he started in APās forum. (You can do a quick Forum Search to look for a thread that closely matches your subject of interest.)
Thank you very much for your comment, I really appreciated it. I agree with everything you said in the first long paragraph. The āfeelā can be very different, as well as interaction between layers, and even covers can combine to result in a very different cumulative outcome.
May I just make one comment here as part of this thread discussion? I understand compression modulus, but my point was that in any sleeping position it is almost impossible to compress latex beyond 40% by an individual under 200 lb, so comperssion modulus is not very relevant in real life situations. Below 40% compression, both Dunlop and Talalay have very similar curve (second image in the article you linked to). So, I just donāt understand when experts on this forum say without reservation that Talalay is softer; I hope someone will explain what they mean because it is not in agreement with the article be in terms of force and pressure (as well as Sleep on latex website). My other main point in previous comments was that often repeated statement on this site that heavier people should sleep on firmer latex goes very much against my personal experience (I am out of $450 because of such comments ).
For clarity and for other consumers who may be following the responses unrelated to OPs original question, I am renaming this portion of the thread to āQuestions about Compression Modulusā and moving the posts to the General forum space. Hope this helpsā¦
I came across this thread while I was researching compression modulus and I had to comment on this because the above statement is just flat out incorrect. As you can see from the work I did testing in my build thread here, depending on the firmness you can absolutely compress the latex layers in use past 40% in both dunlop and talalay depending on the personās shape and BMI. In simple terms the steeper the deflection curve the more the material will conform to your body (people are calling this softer in many cases). Talalay does conform better than dunlop but dunlop does have a more linear reaction to loading (esp with heavy weight, similar to how springs would react under load) which in most cases makes it better suited for the support layers. People that like the mattress very firm or are stomach sleepers may prefer dunlop in the comfort layer as well so there are alot of considerations when choosing your ideal mattress.
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