How to wash thermal underwear?

Thermo-active underwear is a specific type of functional garment, helping to keep the skin at the optimum temperature during various physical activities. The underwear provides a feeling of dryness and comfort. In addition, the insulating properties of thermal underwear protect against the cold on cold days, while allowing the skin to breathe. Thermo-active underwear is lightweight, flexible and adapts well to the body so that freedom of movement is not restricted.

In this article, you will learn how to properly wash your thermal underwear so that it does not lose its properties. We will also tell you which detergent to choose for your natural and synthetic base layers to avoid damaging your clothes.

Washing thermal underwear - what you need to know

Thermo-active underwear is a type of garment that clings to the skin. As mentioned, its primary function is thermoregulation, i.e. the distribution of heat and moisture in such a way as to minimise the risk of overheating. In addition, thermal underwear protects against the cold, and the level of this protection depends largely on the weight of the fabric.

Due to its technical properties, washing thermal underwear requires the use of appropriate techniques and measures to avoid damaging it.

Washing thermal underwear - by hand or in the washing machine?

Most models of thermal underwear can be washed both by hand and in the washing machine. However, before doing so, it is a good idea to read the information on the product label to be sure which washing method to choose.

The graphic below shows the most common symbols used on clothing labels:

Hand washing of thermal underwear

Washing thermal underwear by hand (as opposed to in a washing machine) gives us greater assurance that it will not be damaged. The materials used in thermal underwear can be too delicate to be washed mechanically. This is therefore a safer method, but more time-consuming. Handwashing should be used when the product label recommends it. You can also use this method for minor soiling.

If the underwear is deeply soiled or the material gives off a very intense odour, it is advisable to first soak the garments in lukewarm water (30 degrees C) for 30-60 minutes before washing them properly. In other cases, this step can be omitted. Hand washing can be done by following the steps below:

Pour lukewarm water into a bowl and add the appropriate amount of your chosen thermal linen detergent.
Wash underwear by kneading it (avoid friction as this can damage the garment).
Rinse the laundry several times with water to remove any residual detergent.
Gently squeeze off the excess water, then lay the washed linen on a towel and drain the water.
Lay out your underwear on a dry towel or dryer (lay them flat, without hanging them up).
Leave in a dry and shaded place until fully dry.

Attention! Never dry thermal clothing or underwear on a radiator or in direct sunlight. Improper drying of underwear can lead to damage or fading. Also avoid hanging them on washing cords and dryers with clothespins, as these garments may become deformed. If the use of buckles is necessary, place them on the seams.

Hand washing is also a good way to prepare heavily soiled thermal underwear for machine washing. Before washing in the washing machine, it is a good idea to gently wash the dirtiest area with a small amount of suitable detergent.

Washing thermal underwear in the washing machine

Washing thermal underwear in a washing machine is not significantly different from washing by hand. Similar principles should be followed: wash at up to 30 degrees C, use appropriate detergents and set the spin setting to low speed (in the case of Merino wool underwear, the spin function should be omitted).

It is worth paying attention to the available washing programmes on your washing machine. Most modern appliances are equipped with a mode for washing this type of clothing. This is, for example, the "sport" or "thermo" mode. However, if such a programme is missing from your appliance, you can apply the following tips:

Choose a gentle programme or set the temperature to 30 degrees C and spin on the lowest speed.
Turn the pre-soaked thermal underwear inside out and place in the drum of the washing machine; if you are also washing other thermal clothing at the same time, remember to fasten all the zips.
You can place your most delicate garments in a special laundry bag to minimise the risk of damage.
Pour the appropriate amount of liquid or other detergent into the dispenser for washing thermal underwear.
When you have finished washing, drain the water from the clothes in the same way as when washing by hand; also use the same drying method.

Attention! Do not use softeners, as they can impair the properties of your garment.

How to wash natural versus synthetic thermal underwear?

Choosing the right washing method also depends on the type of material from which the thermal underwear is made.

Typically, the material used in thermal clothing and underwear is divided into three types:

natural - such as Merino wool,
hybrid/mixed - for example, wool with synthetic additives,
synthetic - made entirely of synthetic materials.

You will do the washing of thermal underwear and other thermo garments made of natural and hybrid materials in the same way. Although hybrid underwear is made partly of synthetic materials, more attention should be paid to natural materials.

Washing underwear with Merino wool and hybrid underwearj

Merino wool is a type of specific fabric that is sourced from merinos (sheep that live in Asia), which live in a climate where temperatures throughout the year range from -20 to +30 degrees Celsius. Merino wool fibres are very fine - 1/3 the thickness of a human hair with an irregular, twisted structure. The unique structure of the merino fibres creates air chambers between them, allowing them to trap heated air from the body and wick moisture to the outside.

Merino characteristics
	natural, biodegradable and hypoallergenic
	protects from UV radiation
	has good breathability
	does not absorb unpleasant odours
	is stain-resistant

Because of these advantages, Merino wool thermal underwear is a popular choice for those who enjoy outdoor activities.

How do I wash my Merino wool thermal underwear? Just like other types of wool, that is, gently. If you don't know how to wash this type of underwear, feel free to use the information below:

If you have the option, wash your Merino thermal underwear by hand in water at a temperature not exceeding 30 degrees C; higher temperatures can damage the wool fibres (shrinking or pulling them down).
When power washing, choose a programme for wool or for delicate fabrics; forgo spinning and tumble drying.
Forgo fabric softeners as they will smooth out the porous, twisted fibres of Merino wool, making them lose their properties.
For washing, choose only detergents designed for wool; if you do not have one at the time of washing your thermal underwear, you can use grey soap.
Always dry Merino underwear laid out in a shaded, airy place.

Do the washing of hybrid thermal underwear in the same way as for natural underwear.

Washing synthetic thermal underwear

Although it seems that natural underwear would be the best choice, those made of synthetic materials should not be discredited. Such underwear is more resistant to mechanical damage and dries faster. Synthetic underwear is made of polyesters or polyamides often in combination with elastane. In addition, some models of synthetic underwear are enriched with antibacterial silver ions, which are used, for example, in dressings.

Washing synthetic thermal underwear is somewhat simpler than wool and hybrid underwear, although this does not mean you can do it carelessly. You can wash your synthetic underwear by hand or in a washing machine. When washing by machine, use the programme for sportswear or delicate fabrics and use detergents for thermoactive underwear.

Carry out drying in the same way as with other types of thermal underwear.

Which liquid for washing thermal underwear should I choose?

You already know how to do the washing of various types of thermal underwear, but it is also worth considering what to wash your thermal underwear in so as not to damage it. Conventional washing detergents that we use every day are too aggressive for the delicate structure of thermal underwear and garments, so it is important to use the rightproducts

It is best to use products from well-known and reputable brands, such as: Nikwax and Grangers, to wash your thermal underwear. You can also use these detergents to wash other functional garments.

How often to wash thermal underwear?

Natural underwear should not be washed too often, as Merino wool can become damaged after repeated washing. If the workout was not too intense and there is no dirt on the underwear (underwear in the form of a T-shirt and leggings/getters), just leaving it to air out overnight should be enough.

For synthetic underwear, washing is generally a requirement after each use.

How to wash thermal underwear? - summary

We hope that after reading our article you already know how and in what to wash your thermal underwear. As a quick reminder, we have included below a list of the most important steps you should remember:

Read the labels on underwear and thermal clothing - they contain all the necessary information to do the washing properly.
Only choose detergents designed for the thermal underwear you own - pay attention in the case of natural underwear whether the detergent can be used for this type of underwear. Remember not to use bleach or softeners.
Buckle up the zips, turn the garments inside out - this will protect the garments from mechanical damage during washing and also reduce the risk of prints being damaged.
Soak and pre-wash heavily soiled underwear or underwear that emits a very strong odour - in some cases, simply washing the underwear will be sufficient.
Choose the right programme - set the spin speed to the lowest setting or switch off the function completely. Do not use high temperatures so that your underwear does not shrink or stretch.
Dry your underwear by laying them flat - do not use tumble dryers or lay your underwear on radiators, and try to avoid hanging them on cords with clothespins.

Thermal underwear and preparations for taking thermal underwear in the MILITARY.PL

Our shop offers a wide range of men's and women's thermal underwear in various forms - shirts, leggings, leggings, boxer shorts or bottoms. Our products are made from both Merino wool and synthetic materials. Look out for products from well-known and respected brands, among which you will find: Military Wear, Alpinus, Brandit, Brubeck, M-Tac, Mil-Tec, Fjord Nansen, Helikon, Mil-Tec, Pentagon or Under Armour. We also recommend that you take a look at our range of products for washing thermoactive underwear, so that it stays fresh and in service for a long time.