My word the Ultimate Dreams 13" Gel Memory Foam is extremely hot, way too soft and the edges are kinda scary soft. The heat and complete lack of support was really disappointing. Hopefully they will refund me. Now I am debating on just going normal mattress shopping or trying another online one. This sucks.
Dream Foam Bedding / Brooklyn are being nice and suggesting I try the Arai.
Hi beeze455,
Welcome to the Mattress Forum! 
This model is listed on the Dreamfoam site as one of their softest models, so it would be expected to be quite plush ( I don’t know if it’s “scary” soft, but it is Halloween season :lol: ). And while there are of course no “standard” plushness designation due to the different perceptions, individual preferences and various manners that people can rate a product, it’s usually a good indication that a product will be quite soft when a manufacturer rates it near the top of their plushness scale. But you own personal testing would be the most reliable indicator.
As for sleeping temperature, all foams are insulators to a degree, with memory foam generally being the least breathable, although there are newer versions that breathe better than previous generations. Additionally, you’ll tend to sleep a bit warmer on a softer mattress, as you’ll sleep “in” the mattress more and be more insulated and also have less of your surface area exposed for heat exchange, as opposed to a firmer mattress, which you’ll tend to sleep “on” more than “in”.
Overall, it’s not really possible to quantify the sleeping temperature of a mattress for any particular person with any real accuracy because there are so many variables involved including the type of mattress protector and the sheets and bedding that you use (which in many cases can have just as significant an effect on sleeping temperature as the type of foam in a mattress) and on where you are in the “oven to iceberg” range and because there is no standardized testing for temperature regulation with different combinations of materials … there is more about the many variables that can affect the sleeping temperature of a mattress or sleeping system in post #2 here that can help you choose the types of materials and components that are most likely to keep you in a comfortable temperature range.
In very general terms … the materials, layers, and components of a sleeping system that are closer to your skin will have a bigger effect on airflow, moisture transport, and temperature regulation than materials, layers, and components that are further away from your skin and softer mattresses or foam toppers will tend to be more “insulating” and for some people can sleep warmer than firmer versions of the same material.
Regarding “cooling” memory foams, you can read more about phase change materials in post #9 here and at the end of post #4 here) and you can read more about the various different types of gel foams in [url=https://forum.mattressunderground.com/t/gel-infused-foam--soy-based-foam]post #2 here[url]. In general terms gel foams will tend to have a temporary effect on temperature while you are first going to sleep until temperatures equalize but have less effect on temperature regulation throughout the course of the night. In very general terms … gel and/or other thermal conductive or phase change materials can have “some effect” on the sleeping temperature of a particular material but how much of an effect they will have and how long the effect will last will depend on the specific formulation of the material and on the “combined effect” of all the other materials and components of the sleeping system including your sheets, mattress protector, and bedding. Many thermal conductive or phase change materials tend to have a more temporary effect when you first go to sleep at night or over the first part of the night than they will over the entire course of the night.
Speaking to edge reinforcement systems, there are some comments about edge support with latex or other foam mattresses in post #2 here and the posts it links to. The UD 13" Gel Memory Foam uses a firm polyfoam base, but there is no specific reinforcement system built into the product. Even if there was such a system, it would be unrealistic to expect it to feel too firm along the edge with 5" of plush memory foam place above the polyfoam core, as this would impact the overall sensation of edge support.
While the mattress may be softer than you personally desire, to state that there is “a complete lack of support” is inaccurate. There is information about primary or “deep” support and secondary or “surface” support and their relationship to firmness and pressure relief and the “roles” of different layers in a mattress in post #2 here and in post #4 here that may also be helpful in clarifying the difference between “support” and “pressure relief” and “feel”. Surface plushness and deep support (this mattress does have a good quality polyfoam support core) are two different things, and it seems that overall this mattress is too soft for your preferences.
Dreamfoam is a member here of the site, which means I think highly of them, and they do provide excellent service. I’m glad that they’re being helpful to you with some alternative suggestions. If you don’t find something you like, at least you had the foresight to choose something that has a good return/exchange policy, which is an important consideration for many people when shopping online because of the unknown comfort of products that you may not be able to try out in person
Phoenix
PS, I slightly modified your thread title, as it was misleading.