How Undershirts Keep You Comfortable Year-Round

Ever wondered how an undershirt can keep you comfortable all year round? How is that possible? It comes down to the physics of thermodynamics. Intrigued? Read on ...

When it comes to dressing for comfort, one essential piece that often flies under the radar is the undershirt. Summer or winter, undershirts play a crucial role in regulating body temperature and enhancing overall comfort. How is it possible that the humble undershirt can perform two seemingly opposite roles? Let's dive into the science, the science of thermodynamics, and in particular transfer of heat by convection, and the latent heat of vaporisation.

Let's start with the latter, the "latent heat of vaporisation" may sound like fancy term  in physics and indeed it does indeed have a fancy equation that depicts the maths behind it - see below.

But you don't need to do the maths to feel the effects. Simply pull on a wet tee shirt and stand still for 5 min. Feeling chilly yet? Latent heat of vaporisation simply states that liquids absorb energy as they evaporate. In this case the water in your tee shirt is absorbing energy from your body as it evaporates. Given enough time, the wet tee shirt will become dry, and you will become cold.

When you wear a bamboo undershirt, you get a much more controlled version of the same process. Bamboo fabric is a water absorbing. The cellulose molecules (plant material) that makes up bamboo fabric is hydrophilic - meaning it attracts water at a molecular level. In summer, when you sweat, the water in your sweat is absorbed into the filaments inside the fibres of the undershirt. Once aborbed the water molecules take in heat energy from your body. Once they've absorbed enough energy the water molecules disperse as water vapour through the breathable bamboo fabric. It's like wearing a million little wet tee shirts that keep you cooling throughout the day. Because this process is occurring at the molecular level and because it is spread out through the bamboo fabric fibres there are no unsightly wet patches. Just trillion of water molecules taking a little heat away from your body to gently cool you.

So what about winter then?

Winter is a simple case of insulation. In winter, when you are naturally cooler you are less likely to sweat. Less sweat mean no water to drive the latent heat of vaporisation process described above. What happens instead is good old insulation by trapping a layer of warn air next to your body. Have you wondered why Robert Owen undershirts are made from stretchy fabric and designed to be comfortably body hugging? We design our undershirts this way so there's no draft gaps between your skin and your undershirt. Like any clothing air get trapped between the fibres of the fabric. That air sits like a warm blanked shielding your skin from the colder air beyond. The layer of air may be tiny to you and I but at a molecular level it is vast and the heat trapping effect powerful. The equation below that of Newton's Law of Cooling, which essentially states the rate at which a body looses heat is proportion to the difference in temperature between the body and its surroundings. Simply put the warmer the air directly next to your skin the less heat you will lose from your body.

Again, you know the effect already. The reason wind has such a chilling effect is because it blows away any layer of warm air next to your skin!. Wearing a well fitted undershirt help to trap that layer of warm air underneath your dress shirt next to your skin just where you need it. As it's cool, there is no sweat or water to kick off the summer cooling process. Instead you just have a warm layer of air trapped by a super soft and stretchy bamboo fabric which feel both luxurious and comforting at the same time. That feeling of a gentle warm hug from your undershirt is so nice that you'll miss it when it's not there.

There you have it. The humble undershirt keeps you both cool in summer and warm in winter and its all down to having the right material and the physics of thermodynamics. 

If you'd like to find out more about Robert Owen and why our undershirts are unique in their design, read more about us here.

We hope you've enjoyed the article. Keep comfy in all seasons with advanced innerwear. Better than a vest.