Are Foam Mattresses Hotter Than Spring?
As a general rule, most people overestimate how much foams are responsible for sleeping hot. Research by the Ergonomic Institute in Munich has shown that the duvet determines about 70% of the temperature of your bed. This means your sheets and bedding are primarily responsible for how hot you sleep, not your foam mattress.
While the materials inside your mattress is made of do play a role in determining how hot your bed is at night, selecting the right bedding will have a more significant effect on how hot you sleep than the type of mattress you have. As a general rule, the closer a material is to your skin, the greater the effect on airflow, moisture transport, and temperature regulation and maintains a drier micro-climate, all of which are the most critical factors in sleeping cool.
That being said, memory foam does sleep hotter than most other types of mattresses, including different variations of foam mattresses such as natural latex. There are many reasons why memory foam mattress sleeps hot most of which are related to the chemicals used to make it and how memory foam conforms to your body as you sleep.
Do Foam Mattresses Make You Hot and Sweaty?
There is a common misconception that foam mattresses sleep hotter than spring or coil mattresses. This comes from the perception that all foam beds are made from memory foam. However, in reality, there are many types of foam mattresses with unique material and thermoregulatory properties. Foam mattresses don’t have to sleep hot and can often be much cooler when compared to traditional spring mattresses.
Memory Foam Mattresses Sleep Hot
Memory foam is famous for its ability to contour to the shape of your body. However, the more a mattress conforms to your body, the higher the chance you will have problems with “sleeping hot”. This problem is compounded by the fact that memory foam is made from petroleum by-products instead of natural materials. This means that it is not nearly as breathable as other foams, which further causes heat to be trapped.
Combined, memory foam’s conforming nature and lack of breathability make memory foam mattress very hot to sleep on even when your sheets and duvet are great at thermal regulation.
The greater breathability of other foams which have a more “open” cell structure (like latex or other polyfoams) tend to reduce the heat issues for people who still want the benefit of a conforming mattress by choosing softer “non-memory” foams.
Natural Latex Foam Doesn’t Sleep Hot
For example, natural latex foam sleeps much cooler than memory foam and has been found by research to have “medium” thermo-regulating properties, meaning that they are neither too hot nor too cold to sleep on at night. This allows you the option to select duvet and sheets according to your temperature preferences.
The millions of interconnected microscopic air chambers in latex foam ensure good heat insulation, optimal evaporation of transpiration fluid and constant air circulation, creating good ventilation. Extra ventilation channels are typically inserted during manufacturing in the latex foam. The sleeper’s change in posture during the night creates a pump effect that generates proper air circulation.
Polyfoams Don’t Sleep as Hot As Memory Foam
Another common type of foam is polyfoam or polyurethane foam. While memory foam and polyfoam are made from similar chemicals and materials, memory foam sleeps significantly hotter than polyfoam for a couple of reasons. Primarily, polyurethane mattresses do not contour to the body as much as memory foam. While foams that contour are great for pressure relief, this causes the mattress to trap heat since moisture is not allowed to evaporate and there are no gaps for air to circulate. This is not as common of a problem for firmer foams, which creates pockets of separation between your body and the mattress, allowing air to circulate better.
Spring Mattresses Are Not Cooler Than Foam Mattresses
Springs have little to no impact on hot or cold a mattress is. The spring is the lower-level component separated from your skin by one or two layers of sheets, possibly a mattress protector and the padded mattress top, which is typically stuffed with polyester.
On low-quality mattresses, the padding on the bed may be minimal. However, in general, the higher the quality of the mattress, the higher the chance the mattress has more layers between the mattress cover and the springs. This further increases the distance of the coil unit from the surface of the bed and your body.
If the layers of fabric and materials around the spring core are not breathable, the springs will not affect the temperature of your bed.
More affordable spring mattresses where the coils are close to the surface because the comfort layers of polyurethane and polyester are thin. You will experience no cooling benefits since these fabrics and materials cannot breathe.
So for a spring mattress to be cooler than a good foam mattress, every layer between you and the spring core must be breathable and effective at cooling. The spring core will only be a contributor (albeit a small one) if that heat can dissipates into the spring core level. Despite that, the spring core cannot take all the credit since breathable sheets and mattress covers are mostly responsible for the overall temperature.
Why Do We Get Hot While Sleeping
Many manufacturers fail to realise that moisture control is essential for a bad night’s sleep in mattresses and bedding. When we sleep, we sweat. If that moisture gets trapped in fabrics near our bodies, it can cause us to feel hot and clammy, which typically wakes us up. In order to get rid of this problem, we will throw off the blankets, which causes the moisture to evaporate so fast that we get too cold which prevents us from going back to sleep. We repeat this cycle over and over, ruining any chance of getting a good night’s sleep.
How to Keep a Foam Mattress From Heating Up at Night
The Problem With Cooling Down a Memory Foam Mattress
While it is possible to somewhat cool a memory foam mattress by having cool and breathable sheets, mattress cover and duvet, this can reduce its ability to conform to your body and provide pressure relief. Memory foam reacts to your body heat for it to soften. This is why they are often hard in the winter or when you first get into bed. If you reduce the amount of heat, the memory foam won’t be able to adequately provide the pressure relief most people are looking for.
For this reason, we usually recommend that people who sleep hot avoid memory foam mattresses. Without that heat, memory foam doesn’t work the way it’s supposed to. Instead, it would be best if you opted for a bed with a soft comfort layer. This gives you a similar ‘feel’ to memory foam while also being much more breathable since it has a more open cell structure.
Gel Cooling Memory Foam Pads Don’t Work
The cooling gel was one of the first synthetic materials developed to solve the problems related to hot sleeping caused by polyurethane memory foam, and it is by far the least effective. Created as a marketing ploy, cooling gel has been introduced in mattresses at an affordable price point as a comfort layer with low density and often little support. The main function of including cooling gel for many of these products is to have marketing talking points to alleviate the concerns most people have about memory foam sleeping hot. However, cooling gells are incredibly in-effective for cooling. The majority of cooling gel mattresses and pillows are covered in polyester textiles, since they are also the least expensive component.
The Best Type of Mattress For Hot Sleepers
The best mattress for night sweats is one that either has springs or foam with an open-cell structure. Open celled foams are breathable, which allows cool air to circulate through the mattress at night. Additionally, perforations in mattress foam can help keep a mattress cool. Perefations work in a similar way to how open-cell foams work by allowing air to move inside the mattress.
In most cases, the mattress cover will have a greater impact on whether or not you sleep cool. The best mattress cover for a hot sleeper is made from natural, breathable and moisture-wicking fibres. We use Tencel for our mattress cover as it is an innovative natural fabric that sleeps cooler than linen and is also softer than silk while also being one of the most eco-friendly materials in the world.
We are proud to manufacture a mattress that provides a clean sleeping environment, great pressure relief, unparalled back support, and is designed to keep you sleeping cool naturally.
My goal is to create the highest quality mattresses and pillows for unmatched comfort.
With 30 years of spinal healthcare experience in Ireland as a chiropractor, I learned the value of high quality sleep for living a happy and healthy life.
I have a Chiropractic Degree from Life Chiropractic College West and I am NBCE Physiotherapy certified.
Discover your first good night’s sleep.