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I thought only foam beds retained heat but I've had two innerspring that gave off heat. Assuming that a twin XL or full bed is less dense than a larger bed, would those smaller sized mattresses be less likely to retain heat than a bigger one?

Hi JBR2022,

I thought only foam beds retained heat but I've had two innerspring that gave off heat. Assuming that a twin XL or full bed is less dense than a larger bed, would those smaller sized mattresses be less likely to retain heat than a bigger one?

You are correct that memory foam is the ‘worst offender’ in this regard; but there are a few misconceptions you may be having here. How much ‘heat’ a mattress gives off is determined by the breathability and porousness of the layers closest to the sleeper. Memory Foam will generally be the least breathable and most insulating of the foam comfort materials, so as you noted temperature can be an issue and you’d want to make sure that you don’t choose something with too much memory foam on top that you sink in too deeply as the more you sink into it the more will sleep hot. 2” memory foam layer will retain less of a sleepers heat than a 4” layer of memory foam in the same IFD (indentation force deflection) Lower IFDs (softer foam) and in thicker layers will cause the sleeper to ‘sink’ in more, and more of the body’s heat is trapped in the cradle that is formed, It's difficult to quantify with any accuracy the sleeping temperature of a mattress for any particular person because there are too many variables involved including the type of mattress protector and the sheets and bedding that you use. You can read more about the many variables that can affect the sleeping temperature of a mattress or sleeping system in post #2 here that can help choose the types of materials and components that are more temperature neutral. 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.

A larger bed will allow the heat to better dissipate especially if the sleeper switches positions to a slightly different area of the bed giving a chance for the previous area to cool off. Heat retention has more to do with the breathability of the whole sleeping arrangement and the type of materials used that are closer to the skin, the IFD, and the porousness of the layers closest to a sleeper’s body. The same goes for the innerspring…and innerspring support system provides good ventilation and air circulation for the sleep system, and does not ‘give off heat’ – that’s determined, again, by what layers are on this foundation, their breathability, and how much a sleeper ‘sinks in’ to the comfort layers closest to their skin…are you perhaps thinking of ‘thickness’ rather than bed size?

There are a few good ways to alleviate excess heat without getting into replacing layers; A good cotton or wool cover or organic layer of coconut coir on the top layer will allow air to circulate and heat to dissipate. A mattress topper will likewise help if it is made with a breathable material in the top layer. You do not say if you are trying to resolve ‘sleeping hot’ and what materials are in your mattress, but if you can provide a few more details - we can possibly address your issue in more detail.

I hope this helps,
Basilio

The mattress I have now isn't hot but too hard and sagging. I returned 2 medium softness mattresses because they gave off heat. I'm hoping there's a middle ground I can find with something not too hard and not too hot, though I realize softer beds can give off heat. I would go with medium firm but those are hard to find.

I was wondering if you could make something of what I have below in terms of which mattress might be hotter. Sorry the second one didn't give specifications of inches. Thank yoiu.

one that gave off heat-
.75" PressureSmart™ Gel Memory Foam
1.25" AirFeel™ Foam
1" Plush Comfort Foam
Gel Memory Foam Lumbar Support

one that I'm thinking of getting:-
Serta® PillowSoft ® HD Foam
PillowSoftC Aire
HexCloud™ Gel Memory Foam
Serta® Balanced Support Foam

Hi JBR2022,

The mattress I have now isn't hot but too hard and sagging. I returned 2 medium softness mattresses because they gave off heat. I'm hoping there's a middle ground I can find with something not too hard and not too hot, though I realize softer beds can give off heat. I would go with medium firm but those are hard to find.

Sorry to hear you are still having trouble finding a mattress that suits you. Part of the problem you migt be experiencing is simply the properties of memory foam – these are made to contour to the sleepers body, and therefore they, by nature, will retain the heat of the sleepers, as described in my previous reply. While a softer comfort level will allow you to ‘sink in’ more and therefor have more possibility of retaining your body heat, its’ really in the nature of memory foam to somr extent.

I was wondering if you could make something of what I have below in terms of which mattress might be hotter. Sorry the second one didn't give specifications of inches. Thank yoiu.

one that gave off heat-
.75" PressureSmart™ Gel Memory Foam
1.25" AirFeel™ Foam
1" Plush Comfort Foam
Gel Memory Foam Lumbar Support

one that I'm thinking of getting:-
Serta® PillowSoft ® HD Foam
PillowSoftC Aire
HexCloud™ Gel Memory Foam
Serta® Balanced Support Foam

Just from the specs you’ve given, depending on the density of the Beautyrest which they do not disclose, the thickness of the foam layers would be ostensibly ‘better’ for not retaining heat. Serta, likewise, do not disclose composition, density or thickness of their foams, so its not possible to judge whether you personally would sleep ‘hotter’ on either mattress. The comfort lebvek of a mattress and is unique to the sleeper, and is entirely subjective. You may want to look at the trusted Members of the site who have memory foam offerings, as they do disclose materials, thickness and densities of their products, and are able to better match the desired ‘feel’ consumers are looking for by providing them a small amount of information.

Another option you might look into is using a mattress topper with a breathable material like cotton, wool or coconut coir which would allow more air circulation between you and the top layer of the mattress. Many of our members offer toppers of varying materials and firmness levels and this might provide a cooler sleeping experience. There are also products aimed at hot sleepers like EightSleep and Chillipad Which I have not personally used but you can see in this Post one of our forum member has great reviews on a hydronic cooling system, which, while not inexpensive, has solved his problem with sleeping hot.

Hope this helps,

Basilio