Which Winter Insulation?

On The Insulation Station

Insulation is a battlefield, as Pat Benatar might have said if she wasn't preoccupied with all that more emotional stuff. Fact is that there's a lot of choice out there - down, fleece, synthetic fills like PrimaLoft and variations on all of them - and they all have strengths and weaknesses.

So to help you decide what's likely to work best for you, we've gone through a whole bunch of winter warmth options and pointed out the pros and cons of each and where they're happiest. Before we get into the details though, a quick note on how insulation works.

How It Works

Simple, pretty much all insulation works by trapping a layer of air close to your body which your body heat then warms creating a barrier to reduce further heat loss. That's why big down jackets and duvets may feel slightly cool at first before your body has heated the air trapped between the feathers.

It's also why windproofing is important in anything other than still conditions. Without it, the warm layer of air close to your body is stripped away and you lose heat warming it all over again. And again. And again... 

Finally, it also explains why humidity is important. Dry air is a better insualator than the sort of damp stuff we get in the UK. That's why a sleeping bag that's warm at -20˚C in the Andes can feel cold at -10˚C on a dank Scottish loch side, the air inside it is simply transmitting heat outwards more effectively, which means you feel less warm.

The Options

We've broken the options down into down, micro-baffled down, synthetic fills, hybrids, fleece and shelled fleece or pile/Pertex. They all have pros and cons.