Insulating Layer for Warmth

High-neck insulating layer

I like the neck on my mid-layer to zip up to my chin.

The purpose of the insulating layer or mid-layer is to help you retain heat by trapping air close to your body.  It is worn over the base layer and it must have the ability to not only keep the warmth in, but to also allow perspiration to pass through it. The insulating layer can range from lightweight fleeces and wool sweaters to full-on puffy down jackets; it just depends on the temperatures you are going to be facing.  Let’s take a look at the different materials available for  this layer.

Insulating Layer Materials

There are quite a few materials that you can choose from for your insulating layer – and all of them are good.  It really just comes down to your own preference and the conditions you’ll be facing.  Many people like natural fibers such as wool and goose down. Merino wool sweaters and shirts offer soft, reliable warmth and keep on insulating even when wet. For very cold and dry conditions, goose down is the absolute best as it has an unbeatable warmth-to-weight ratio.  Other people like polyester fleece insulating layers as these fabrics come in different weights and they have been treated in such a way that the fibers stand up and trap air, which gives the garment its insulating ability. Lets break these down and compare them – so you can choose which ones would be best for you and your situation.

Polyester Fleece

* Available in a variety of styles and thicknesses.  (Same definitions as base layer here).
* Durable, lightweight and fast-drying.
* Breathable – Transports moisture away from the body well.
* Sometimes comes with wind-stopping liners built in (you may not want this – see below).
* Maintains some insulating ability even when wet.
* Less expensive then wool or down.

Many manufacturers make fleece mid-layers and really, all of them are good.  Make sure that you look at what the weight is on the fleece that you are buying.  You will most likely want a couple different weights depending on what sort of temperature variations you are going to face with where you ski.  Here are some of the best brands: Black Diamond, Columbia, Helly Hansen, North Face, and Patagonia.


* Is a good natural insulator, even when wet.
* Breathable – Transports moisture away from the body well.
* Merino wool has a very fine fiber and feels good next to the skin for most people.
* Bad points are it can take a long time to dry and it can be bulky to wear.
* Typically not as durable as polyester.

You won’t find a real large selection of wool insulating layers – at least I couldn’t find a lot.  There are some well established and trusted brands though and they are: Icebreaker and Smartwool.  Try them out. I know that you’ll like them.  I swear by my Icebreaker stuff – love it.


* Very efficient insulation with high loft and best warmth to weight ratio
* Bad point is it loses its insulating properties when it gets wet.
* Typically more expensive and harder to maintain then polyester or wool.

When it is going to be really cold – I always go with my down insulating layer.  It really keeps me warm for sure.  There are a number of manufacturers that make down sweaters and down mid-layer jackets.  They are pricey, but if you want the best for staying warm, then these are your items.  Well known and trusted brands are Marmot, Mountain Hardwear, Northface and Patagonia.  All are very good.


Those are the most common insulating layer materials.  Now some other things you’ll want to consider when choosing your insulating layer.

* When my neck gets cold, I get cold – so I prefer a high zip up collar on my insulating layer, one that goes all the way to my chin. This high collar keeps my neck warm and I can unzip it to let off heat as needed if I get too warm.

* Another thing – you’ll find that two thin layers will be warmer than one thick layer.  Remember, in order to retain heat you need to trap air and you’ll trap more air with two thin layers as compared to one thick layer. It also gives you an option to take off one of the thin layers if you get too warm.

* Fleece purchased with a wind-stopping membrane (which comes under various brand names) may not be something you want if you’re going to be sweating very much.  It has a reputation of not breathing well and can thus leave you wet inside the layer. Some of these membranes breathe better that others, but just know that none of them breathe as well as fleece without this membrane.

* One other thing that you might choose for your insulating layer is a vest.  You can find vests in all the above materials and they can be used right over your base layer if it’s not going to be very cold – or they can be worn over your first insulating layer if it is going to be cold.  They give you an extra layer to keep your core warm without adding more bulk to your sleeves.  I love them and have both fleece and down vests in my closet.  Some great vests are made by all the major manufacturers.  Nice fleece ones can be found by Patagonia, Marmot and Columbia.  Very warm and useful wool vests can be gotten from Icebreaker and Ivanhoe.  Great down vests can be gotten from Northface and Mountain Hardwear.


There you have it – your rundown on the insulating layer.  Put this data to use and get yourself all set up to stay warm on the hill and have a good time.

See you on the slopes.

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