THE KNOWLEDGE

DOWN VS ETHICS The brands sold in ‘proper’ outdoor stores aim to use ‘responsibly sourced’ down, which comes from animals that were slaughtered for the food industry (i.e. they weren’t harmed by the downremoving process). Less scrupulous brands may use down that was liveplucked: a horrendous and painful experience for the animals concerned. Synthetic fills aren’t free of ethical and ecological concerns (plastics, detergents, labour conditions etc) but these are common across the industry. WHY MIGHT I CHOOSE SYNTHETIC FILLING? It is usually cheaper, more water-resistant and often more breathable, with no concerns around animal welfare. And some variants, for example Primaloft Thermoplume (pictured), are coming close to matching the performance of natural down. WHAT IS ‘FILL POWER?’ Manufacturers usually advertise a ‘fill power’ of between 650 and 900. It’s not a measure of heat, it’s a volume — the amount of cubic inches one ounce of down occupies. For example, one ounce of 800 fill-power down will occupy 800 cubic inches when compressed. But in reality it’s not really that helpful to choose a jacket by its fill power, as it depends how much is used: a jacket with six ounces of 800 fill will be about as warm as one with 12 ounces of 600 fill.