SUL 1.5 Down Vest

The SUL (super ultralight) series garments are aimed at pushing weight as low as possible for a given fill amount, without compromising function. They are down sweaters in the strictest sense. Like a knit sweater, no zippers, no pockets, no linings, no webbing, just insulation in the form of down in a nylon shell. Now available with zippers and pockets.

Fill type – 900fp Hyperdry goose down

Fill weight (approximate) – Calculated loft is 1.5″. Total fill weight is not a relevant metric for warmth.

Total weight (approximate, less with drawcords removed) – 3.6oz (small)

The goal with the SUL 1.5 down vest was to make the lightest vest possible for solid 4 season use. It gets the same shell as the SUL .75 and SUL 1.1, except the baffle spacing is increased to 6″ to limit cold spots and maximize loft. Calculated loft is increased to 1.5. It’s incredibly warm with over 1.5″ of loft between baffles and very few cold spots. I estimate this as full winter level warmth. Comfort range well below freezing. It has an ultralight, removeable chock cord cinch at the neck and at the bottom hem to keep out drafts.

A puffy is most often used as an inactive layer for stops, at camp, or to help boost a sleep system. They don’t make for very good active layers since your sweat can easily compromise the down fill. This makes a zipper for ventilation a somewhat frivolous feature that can add a significant amount of weight and bulk. Pockets can be nice to have, but they often add a big chunk of weight and bulk and compromise the performance of a jacket by creating cold spots and by pulling insulation flat when there is weight in them. All non-essential sewn through lines have been eliminated so the down can loft and cold spots are reduced. Simplicity and reduced weight and bulk are not the only benefits of all this. Leaving off many tedious features also reduces my labor and allows me to offer a very affordable jacket at an extremely low weight.

It’s meant to be used with a modular hood or head insulation, but can be built with an integrated hood as well.

More warmth out of less fill Sewn Through Baffle Construction and Its Effect on Warmth – Timmermade

These are now available with zippers and pockets, but one should expect each of these to reduce the effectiveness of these garments. The zipper isn’t too bad, but it’ll increase the cold spot in front, and add a chunk of weight. The pockets will add two big cold spots on the sides and placing weight in them can cause shell tension and loft loss. The design of them is intended to limit this effect, by attaching the pocket to points that transfer load up to places that already have sewn through spots. However, it is inevitable that weight will still pull some loft flat. The wearer should be aware of this tendency to try to limit the weight placed on the shells. Storing light things and warming your hands with them supported by something other then the pocket will be less detrimental.