Mimicking down has always been the aim of synthetic insulation designers. Thermoball, designed by The North Face and Primaloft, is the latest attempt and the closest yet in my opinion. Rather than sheets of insulation it consists of small clumps of fibre that resemble down clusters. To prevent these moving about in the garment many little compartments are needed, giving Thermoball garments a distinctive patterned look. This also means there are many potentially heat-leaking seams. I haven’t found this a problem though and I reckon the Thermoball Hoodie is the warmest garment for the weight of all those tested. I used the jacket for ski-touring and hillwalking in the Cairngorms and found it breathable, water‰ЫФresistant and fast drying.

The design is fairly basic with just two pockets that are accessible when wearing a hipbelt, though the bottom of them is cut off, and a non-adjustable hood. The latter has an elasticated rim but it’s not as stretchy as on some other hoods and can be blown back by strong winds. Thermoball is also very compressible and the Hoodie can be stuffed into one of the pockets, though I’d only do this if absolutely necessary.

First published: Oct 2014