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What is 3M™ Thinsulate™ Insulation?

How Thinsulate Insulation works

3M™ Thinsulate™ Insulation is used in your jackets‚ pants‚ gloves‚ hats and boots to help keep you warm when it’s cold outside. The unique microfibers or fine fibers that make up Thinsulate insulation work by trapping air molecules between you and the outside. The more air a material traps in a given space‚ the better it insulates you from the cold outside air. Because the fibers in Thinsulate insulation are finer than the fibers used in most other synthetic or natural insulation‚ they trap more air in less space‚ which naturally makes Thinsulate insulation a better insulator. So we haven’t repealed the laws of nature with our thin insulation; we’ve simply improved them…to help keep you warm.

  • breathable
  • moisture-resistant
  • both machine washable and dry-cleanable
Tips for Choosing Boots
We asked Sam Coalson‚ avid outdoorsman and footwear extraordinaire for Rocky‚ for some tips for choosing the right footwear for your activity; Click here to read Sam's advice.

[pdf‚ 192KB]

Will Steger‚ Polar Explorer‚ tips for Staying Warm
In order to get the best advice on how to stay warm when you’re out in the cold‚ we asked someone who has been there – polar explorer‚ Will Steger. Click here to read Will’s six easy tips to stay warm when it’s cold outside.

[pdf‚ 2MB]

My feet get cold
Here are some tips for keeping your feet as warm and comfortable as possible. Make sure that your boots fit properly and that you start with warm‚ dry feet and footwear. These are just some of the recommendations that you can read about above.

[pdf‚ 145KB]

Guidelines to Dressing Warm
The basic guidelines for dressing warm in cold weather are to cover all body parts‚ to stay dry and to dress in layers. Read about how 3M™ Thinsulate™ Insulation can help you dress warm.

[pdf‚ 167KB]

The Physics of Insulating
How your body uses and loses heat
Scientists have found that the human body sitting at rest consumes 4.7 kilocalories/hour/square foot of body surface area and transfers this energy into heat.

When thinking about heat loss‚ it is important to remember that heat loss is affected by:

  • body temperature
  • outside air temperature and wind speed
  • distances between the insulation fibers
  • thickness of insulation
  • fiber size
Clo Defined
The clo unit is defined as the amount of clothing required by a resting subject to be comfortable at a room temperature of 70°F (21°C). Clo-value is analogous to R-value for rating house insulation. For example‚ 1 R-value = 1.137 clo-value.
Normal Clo Values
Nude person clo = 0.0
Typical business suit clo = 1.0
Clo Vaues are Additive
Summing the clo values of individual components will approximate the total system clo.
Determining Effective Clo
Total clo is estimated by adding the clo values of the components and correcting for surface area‚ fit‚ and air layer effects. This procedure was developed by the American Society of Heating‚ Refrigeration and Air conditioning Engineers.
Effect of Activity Level
The insulation required by an individual to maintain comfort is markedly affected by activity level. This factor must be considered when choosing a garment for a particular activity.
Staying Warm
Thermal comfort is achieved by balancing three factors:

  • rate of heat production by your body
  • insulation value of your clothing (clo)
  • environmental temperature
Of those three‚ it’s easiest to alter the insulation value of your clothing. To do this we need to understand how‚ exactly‚ insulations work.

Insulations work in two ways: first‚ by trapping air. The more air trapped‚ the more efficient the insulation. Second‚‚ by reflecting back the body’s radiant heat.

The unique microfibers of 3M™ Thinsulate™ Insulation are about ten times smaller than the fibers of most other synthetic insulations‚ which means they’re much more efficient at trapping air…and more effective at keeping you warm. It also means we can pack more fibers into the same space‚ where they can reflect back more of the body’s radiant heat.
Thinsulate Insulation - Fibers thin The fibers of Thinsulate insulation are fine‚ making them ideal for trapping insulating air and reflecting back the body’s radiant heat.
Thinsulate Insulation - Fibers thick The fibers in 6-denier polyester are much thicker and not nearly as efficient at trapping air or reflecting back body heat.
Neither repeated machine washings nor dry-cleanings markedly affect the performance of Thinsulate insulation. Tests have shown‚ in fact‚ that Thinsulate insulation’s average “clo” remains relatively unchanged even after repeated cleanings.

Thinsulate insulation is the smartest choice if staying warm is important to you. When you compare equal thicknesses‚ the original “warmth without bulk” Thinsulate insulation offers almost one-and-one-half times the warmth of down‚ and twice the warmth of other high-loft insulation materials.

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