Memory Foam and Heat

Memory foam mattresses are sought-after all over the world. Unlike coil sprung models, they adapt to your body’s unique contours and let you sink into a flexible sleep.

While a popular choice, some users have struggled to keep cool during the warmer seasons. However, there’s no need to avoid memory foam. You simply need to be smart when spring and summer approach.

too hot to sleep

Wondering how to prevent memory foam heat? You’ve come to the right place.


Why does memory foam retain heat?

Foam is a natural insulator, and it traps more warmth than a coil mattress. The foam material needs to be dense enough to support your body – but this means that air circulation between you and the mattress is constricted.

There’s a trade-off: the more foam you get, the more pliant the mattress, but also the hotter it may become. Generally speaking, a firmer mattress provides more opportunity for ventilation between your body and the bed, which will help keep you cool. With a softer, more flexible mattress, your body temperature permeates the surface and stays there. Air can’t circulate as well unaided because you are lying against the foam inserts. Sleeping with a partner will also increase the amount of body heat trapped in the mattress.

An analysis of more than 25,000 sleepers reported that 9% of people think their memory foam mattress is too hot. 15% had similar feelings, but not to the extent that their mattress was uncomfortable. Still, almost 1 in 10 of those surveyed had real concerns, which is an issue. You’re entitled to a fantastic sleep – especially when you’ve paid good money for it. 

Some mattress brands have introduced gel inserts to offset heating issues. These are useful, but only diminish the heat temporarily. Once the gel inserts absorb heat to their maximum capacity, they actually begin to retain it.

But this shouldn’t be a reason to give up memory foam altogether. Let’s examine the tips and tricks to stay cool and cosy on the bed you love…


How to prevent memory foam heat

Choose thinner, all-natural sheets and bedding

Instead of changing the mattress, swap your typical bedding for something lighter. Look for materials that are better at creating air flow. Bamboo, linen and cotton have breathable properties.

It’s also a good idea to check the thread count, which lets you know the density of the materials you’re looking at. A count of 400 or more may seem luxurious, but doesn’t offer the best breathability – instead keep to 200-350. Egyptian cotton is a good choice as the fibres are long and thin, allowing for airflow.

Changing your pillows can also help to keep you cool at night. Like sheets, pillows come in a range of materials and have their own thread count, which gives you a grade of comparison. Bamboo is a popular choice, since it’s hypoallergenic and fairly affordable. Some gel-based pillows are marketed as having ‘cooling’ properties too. Turning your pillow over can additionally provide a quick solution – allowing you to experience the cooler side now and then.

Change your duvet 

Thread counts aren’t the only measure of thickness and comfort. Duvets have a ‘tog’ system, which refers to the temperate qualities of a given area. It’s also used in carpets.  An ideal spring/summer duvet tog is between 1 and 7. You’ll want a microfibre item that doesn’t weigh too much. Review different summer duvets so you get the perfect one for you at a decent price.

If you’re buying for children, lower the maximum tog density to 3.5 or 4. Kids don’t get quite as hot as adults do.

Wear cooler pyjamas

Memory foam and heat retention is less trouble when you have lightweight, breathable PJs to pull on before bed. Silk and cotton are once again the favourites for a sound sleep. Disregard flannel, wool and fleece until the season turns.

If you’re used to the classic pyjama set, try wearing a vest or shorts instead. Sleeping naked can be great but it’s not for everyone. Experiment, and see what works best for you.

Make clever use of ice and water

Sometimes the most appropriate solutions are the most surprising. Take ice packs, for example – when carefully applied around your arms, legs, chest and belly, they can lower your body temperature before sleep. Deposit an ice pack in a towel or pillow case and use it just like you would a hot water bottle. Even holding a cold, damp flannel on your forehead can work wonders whilst drifting off.

Elsewhere in the room, fill a bowl with ice water. Plug in a fan and aim it over the bowl towards your bed. You’ll get a sustained blast of icy air, bringing the room temperature down over the course of the night. Ensure the fan is blowing partly onto the ice itself for maximum effectiveness. This is a cheap and repeatable way to counter memory foam heat.

Open your windows

It may seem like an obvious solution, but many people forget to leave a window open at night. Or they may be reluctant to – earplugs can help with any noise coming from the street, however, whilst bug zappers deal with flies, moths or other insects that may flutter inside.

Small breezes are better than nothing, so the window should be open continuously on hot spring and summer nights.

Avoid food or hot drinks before bed

As a rule, it’s wise to leave a few hours between eating or drinking anything hot prior to sleep. A warm dinner or spicy meal, as well as a cup of tea or coffee can raise our temperature. As such, wait two or three hours before hitting the sheets. You’ll be cooler for it.

However, it is a good idea to keep a glass of water by your bedside in case you wake up thirsty – sweating can cause you to dehydrate.

The role of intelligent mattress design

So far, we’ve made the argument that it’s what’s on top of your mattress – not the item itself – that may be keeping you up at night. While that’s true, it’s only half the picture.

The classic memory foam model is a densely packed rubber matrix. Whether it’s natural or synthetic, the foam structure traps heat very effectively. Your sweat lingers too. Yet as innovations have sprung up in the market, expectations have grown, which has led to a more balanced take on memory foam. As our knowledge has increased, so has our ability to make mattresses that don’t warm up so quickly or uncomfortably.

The answer lies in layering. A hybrid mattress, blending spring and foam features, airs out your heat with structural interplay from one section to the next. Instead of thick, cloistered materials, you get room to breathe. Moisture and heat retention are dealt with as you settle into the luxurious feel of foam.

There isn’t a formula that suits everyone – that’s why customised mattresses are the way forward. To illustrate this, we’d like to show you our own designs.

Enter… a custom hybrid like no other

Over the years, we carefully considered the memory foam and heat retention debate. We knew there must be a method for better, more considerate mattresses. Eventually we landed on a five-stage composition with unique foam inserts. Why are they so special? Because, for the first time, you can choose how firm the memory foam is to suit you.

The Nrem and DUO mattresses are hybrid creations, made up of individually wrapped springs and foam layers. Both have adjustable comfort levels. You can select a density that suits you, or your partner, and tweak it at any time. This is matched to 1,000 pocket springs on the bottom, giving more support and long-lasting properties than other memory foam models. There’s also a 4cm-deep cooling layer under the hypoallergenic top cover – it’s made with open-cell fabric that disperses excess heat. In the spring or summer, it’s a godsend. And, most importantly, you don’t have to buy another mattress when the chillier winter months begin again.

With our cooling tips in mind, there’s every reason to look forward to your bed, night after night. If you’re wondering how to prevent memory foam heat, the solution is here. Simply browse our mattresses on the Tweak site or speak to us for more guidance.