When ThermoBall™ first hit the scene, my mother was an early adopter. An avid traveler, she often visited colder climates: Moscow, Anchorage, Vancouver, and so on. The lightweight and compressible jacket stowed easily in a carry-on or suitcase, and it proved a warm midlayer in a wide range of conditions.
The next year, my mother gave my sister and I each a ThermoBall jacket as holiday gifts. My sister reports watching Patriots’ games from plenty of nosebleed seats, and her ThermoBall keeps her warm every time. It even still has loft, and the synthetic fill retains warmth when it rains. She’s always fine at the top of the stands.
You see, all insulation works by trapping warmth in dead space, air pockets created by the fill material of the jacket. Loft, the qualitative measurement of dead space, is determined by the puffiness of the jacket’s baffles. We don’t call these coats “puffies” for no reason.
There are two basic kinds of insulation when it comes to winter jackets: down and synthetic. Personally, I prefer the latter. Down compresses more easily, and quality down provides greater warmth for comparatively less weight than almost all synthetic alternatives.
But synthetic fills offer significantly more versatility. Soaked or moistened down jackets lose loft and heat. Wet synthetic insulation retains warmth. A wet synthetic jacket will dry rapidly too, and in extreme survival scenarios this can save your life. For all its virtues, down will never outperform synthetic fills in wet or humid conditions, and when you live in the northeast it’ll be wet and humid all year long. Of course my mother, an avid New Englander, fell for ThermoBall.
But what really distinguishes ThermoBall™ jackets?
ThermoBall is unique; for warmth, weight, and compressibility, it actually mimics approximately 600 fill power down. Put simply, it combines the benefits of down and synthetic insulation. This took years of co-development by The North Face and PrimaLoft, the world’s leading supplier of synthetic insulation, and it’s been an immediate game-changer.
Lightweight and compressible synthetic-filled jackets are more and more common these days. Patagonia claims its Micro Puff® outperforms down, and the Nano Puff® certainly comes pretty close. You’ll find options from all different brands, but I’ll always be partial to ThermoBall.