How Does A Wetsuit Work?

If you were to dive into the sea fully clothed and begin surfing or swimming, you would quite quickly become freezing and bogged down with the weight of the wet material. So why is it that when we put on a tight rubbery onesie, we are suddenly warm and able to enjoy the sea for hours at a time?

At the wetsuit centre, we have a range of high-quality men's and women's winter wetsuits, as well as 5mm wetsuits for juniors and children, to keep you warm in the winter swells.

How Do Wetsuits Keep You Warm?

To understand how a wetsuit works to keep you warm, we need to understand the basic principles of thermodynamics.

Mens winter wetsuits

The Physics Behind Wetsuits 

When two things are of different temperatures, the molecules that make up these things are moving at different speeds. For example, the molecules that make up a hot cup of tea vibrate faster than the molecules in the milk you are about to pour into it. 

When you pour the milk into the hot cup of tea, the two liquids mix together and the energy from the hot tea transfers to the cold milk resulting in the slowing down of the hot tea molecules and the temperature reduction. This transfer of kinetic energy is called heat conduction. 

You can also see this kinetic energy transfer in the heating up of the mug when the hot water is poured in, or the increased air temperature above the cup of tea as the steam evaporates as heat conduction can also happen between solids, liquids and gases. 

This same principle is used in the technology of wetsuits. 

How A Wetsuits Works

We know that because liquid molecules are far denser than air molecules, one of the best ways to insulate a body against heat loss is with air particles. We see this in animals such as otters, whose layer of thick undercoat hair traps air particles between the mammal's skin and the cold water, reducing the amount of water that contacts the skin. This then reduces the level of heat conduction.   

A wetsuit also consists of layers of material, just like an otter. 

The Water Resistant Layer Of A Wetsuit 

The first layer on the outside of a wetsuit and the one first in contact with the cold seawater is thin and flexible water-resistant material. The most common materials, such as spandex or nylon,  offer the necessary flexibility to perform the full range of motion required to surf. 

With the pressure to become more sustainable in recent years, the wetsuit industry has been manufacturing these out of recycled nylon or spandex. 

The Neoprene Layer Of A Wetsuit 

When it comes to thermal protection, this is the most critical layer. 

Each manufacturer had designed and created a patented neoprene technology specific to their brand. However, the basic principles are still the same across the board. 

Neoprene is constructed of some type of ​​synthetic rubber that is produced by the polymerisation of chloroprene. The neoprene contains little pockets of nitrogen molecules within the rubbers, creating an almost porous surface. As we mentioned above, air does not conduct heat as efficiently as water does; therefore, the nitrogen particles embedded in the neoprene transfer less of the kinetic energy from your body to the surrounding cold seawater, resulting in you staying warmer.

Two surfers using wetsuit to stay warm

The Thermal Lining Of A Wetsuit 

The next layer in a wetsuit, the internal layer, is often some type of extra thermal protection. Again this varies between brands and wetsuits as some require specialised properties. 

Almost all higher-end wetsuits that are worth the hype are built with some type of synthetic-fleece lining rather than the more basic nylon lining. The benefits of a synthetic fleece lining are that it often provides more thermal insulation and can be faster drying than its nylon counterpart. 

The Trapped Water 

The final layer of a wetsuit isn't one that is added in the factory but one created when using the wetsuit, and it's the layer of water that is trapped between the wetsuit and the skin. 

When the seawater flushes through the suit when you first hit the water, it fills the space against the skin. This water then heats to your body temperature and remains there, keeping you warm. 

How An Ill-Fitting Wetsuit Can Make You Cold 

When shopping for your first wetsuit, you will find countless articles stressing the importance of a wetsuit fitting you properly. As we stated above, the layer of water trapped between the wetsuit and you play a substantial part in keeping you warm. This is because an ill-fitting wetsuit which is baggy and wrinkled in areas of movement will cause water to flush through continuously. If the water is constantly entering the wetsuit, you will not only lose the warmth of the water previously there, but you will also expel more thermal energy, repeatedly reheating that trapped water to your body temperature.

Check out our wetsuit sizing guide to ensure you or your child has the perfect fitting wetsuit.