Criterion – ‘the standard by which all others are judged’

 

Down Sleeping Bags

 

Down Sleeping Bags

The BEST Polish GOOSE DOWN with … the BEST Japanese PERTEX fabric

Criterion sleeping bags – light as a cloud
very light ……. very warm

Sleeping Bag Construction

Sleeping Bag Construction

What are Baffles? Why are they important?

Down sleeping bags are much more complicated than you may think. They are much more than two pieces of fabric with a down fill. In order to maximise warmth to weight ratios, down sleeping bags take a lot of skill to design and manufacture. As with a duck paddling on water where most of the the action is below the surface, this is the case with down products.

Within the sleeping bag’s shell are a number of chambers called Baffles. Baffles contain the down used to insulate. The better their design, the better the performance of the sleeping bag. To insulate efficiently the down has to loft, which means to expand as it traps warm air. Too much space in the baffle is inefficient as the down disperses. Too little space constricts the down and it can not loft fully.

There are a number of different types of baffles. All have advantages and disadvantages, which vary depending upon the type of product.

In this section five types of baffle are examined,

  • Stitched Through Baffles
  • Boxwall Baffles
  • V Baffles
  • Trapezoid Baffles
  • Brick Baffles

Stitched Through Baffles

Boxwall Baffles are the simplest answer to some of the disadvantages of Stitched Through Baffles. The creation of side walls (as seen in the diagram) serves two purposes. Firstly the down contained within the baffle is able to loft fully and insulate better, as the ends of the baffle are not being pushed together by stitching. Secondly there is no stitching that goes directly from the inner to the outer shell, this markedly reduces body heat lost.

Boxwall Baffles are the lightest baffle design with a side wall. Our two lightest down sleeping bags the Quantum 200 and the Ultralight 200 are made with Boxwall Baffles on both the top and base. All of our other down sleeping bags are constructed with a Boxwall Baffle base.

Several types of boxwall designs exist, including rectangular, diamond shape and curved. They all share vertical baffle sidewalls.

Stiched Through Baffle Cross Section
This diagram shows a cross section of a Stitched Through Baffle. (A) Body heat is lost through the stitching, which creates cold spots. (B) The absence of a side wall does not allow the down to loft fully around the edges of the baffle which increases the effect of the cold spots at (A). (C) Body heat is trapped keeping in warmth.

Boxwall Baffles

Boxwall Baffles are the simplest answer to some of the disadvantages of Stitched Through Baffles. The creation of side walls (as seen in the diagram) serves two purposes. Firstly the down contained within the baffle is able to loft fully and insulate better, as the ends of the baffle are not being pushed together by stitching. Secondly there is no stitching that goes directly from the inner to the outer shell, this markedly reduces body heat lost.

Boxwall Baffles are the lightest baffle design with a side wall. Our two lightest down sleeping bags the Quantum 200 and the Ultralight 200 are made with Boxwall Baffles on both the top and base. All of our other down sleeping bags are constructed with a Boxwall Baffle base.

Several types of boxwall designs exist, including rectangular, diamond shape and curved. They all share vertical baffle sidewalls.

Boxwall Baffle Cross Section
The Box Wall Baffle is the simplest baffle with a side wall. (A) Due to the side wall much less body heat is lost through stitching when compared to Stitched Through Baffles as inner stitching does not meet the outer stitching. (B) The side wall allows down to loft much more fully around the edges of the baffle and decrease the possibility of cold spots. (C) Body heat in the centre of the baffle is trapped and helps to keep the bags temperature stable.

V Baffles

Boxwall Baffles are the simplest answer to some of the disadvantages of Stitched Through Baffles. The creation of side walls (as seen in the diagram) serves two purposes. Firstly the down contained within the baffle is able to loft fully and insulate better, as the ends of the baffle are not being pushed together by stitching. Secondly there is no stitching that goes directly from the inner to the outer shell, this markedly reduces body heat lost.

Boxwall Baffles are the lightest baffle design with a side wall. Our two lightest down sleeping bags the Quantum 200 and the Ultralight 200 are made with Boxwall Baffles on both the top and base. All of our other down sleeping bags are constructed with a Boxwall Baffle base.

Several types of boxwall designs exist, including rectangular, diamond shape and curved. They all share vertical baffle sidewalls.

V Baffle Cross Section
V Baffles are the most thermally efficient side wall baffles. (A) Less heat is lost through stitching. Outer Shell stitching is not directly opposite inner bag stitching (B) Angled side walls contain the down and reduces migration within the baffle. This reduces cold spots. (C) Body heat is trapped and helps to keep the bag’s temperature stable.

Trapezoid Baffles

Boxwall Baffles are the simplest answer to some of the disadvantages of Stitched Through Baffles. The creation of side walls (as seen in the diagram) serves two purposes. Firstly the down contained within the baffle is able to loft fully and insulate better, as the ends of the baffle are not being pushed together by stitching. Secondly there is no stitching that goes directly from the inner to the outer shell, this markedly reduces body heat lost.

Boxwall Baffles are the lightest baffle design with a side wall. Our two lightest down sleeping bags the Quantum 200 and the Ultralight 200 are made with Boxwall Baffles on both the top and base. All of our other down sleeping bags are constructed with a Boxwall Baffle base.

Several types of boxwall designs exist, including rectangular, diamond shape and curved. They all share vertical baffle sidewalls.

Trapeziod Baffle Cross Section
Trapezoid Baffles are the ideal mix of the best qualities of Boxwall and V Baffles. (A) Less heat is lost through stitching than in Boxwall and Stitched Through Baffles, shell stitching is not directly opposite inner bag stitching (B) Angled side walls contain the down and reduces migration within the baffle reducing cold spots. There are less baffles than in a V shaped design, this means less weight, but at the cost of some thermal efficiency (C) Body heat is trapped within the baffle keeping the temperature stable and comfortable.

Brick Baffles


Brick Baffles are used for extreme cold weather down sleeping bags, and make use of two layers of offset Boxwall baffles. Trapezoid and V baffles are more thermally efficient than a single layer boxwall baffle, but in situations where much more down is needed Brick Baffles provide extremely high levels of insulation as well having a high warmth to weight ratio. The additional weight and costs of double Trapezoid and double V baffles would not be commercially viable.

Our Expedition 900 and Expedition 1100 down sleeping bags use a Brick construction.

Brick Baffles
Brick Baffles are used on extreme cold weather bags, (A) Offset stiching minimise heat loss (B) two layers of baffles, allow down to be contained and loft (C) More insualtion traps body heat and helps to keep the bag’s temperature up and you comfortable in the most extreme conditions

Differential Fill

Boxwall Baffles are the simplest answer to some of the disadvantages of Stitched Through Baffles. The creation of side walls (as seen in the diagram) serves two purposes. Firstly the down contained within the baffle is able to loft fully and insulate better, as the ends of the baffle are not being pushed together by stitching. Secondly there is no stitching that goes directly from the inner to the outer shell, this markedly reduces body heat lost.

Boxwall Baffles are the lightest baffle design with a side wall. Our two lightest down sleeping bags the Quantum 200 and the Ultralight 200 are made with Boxwall Baffles on both the top and base. All of our other down sleeping bags are constructed with a Boxwall Baffle base.

Several types of boxwall designs exist, including rectangular, diamond shape and curved. They all share vertical baffle sidewalls.

Differential Cut

Boxwall Baffles are the simplest answer to some of the disadvantages of Stitched Through Baffles. The creation of side walls (as seen in the diagram) serves two purposes. Firstly the down contained within the baffle is able to loft fully and insulate better, as the ends of the baffle are not being pushed together by stitching. Secondly there is no stitching that goes directly from the inner to the outer shell, this markedly reduces body heat lost.

Boxwall Baffles are the lightest baffle design with a side wall. Our two lightest down sleeping bags the Quantum 200 and the Ultralight 200 are made with Boxwall Baffles on both the top and base. All of our other down sleeping bags are constructed with a Boxwall Baffle base.

Several types of boxwall designs exist, including rectangular, diamond shape and curved. They all share vertical baffle sidewalls.

Differential Cut
A differential fill means there is more insulation in the top of the bag than the base. This is because the body’s weight compresses the down in the base and it is not as thermally efficient. Body heat rises and it is trapped in the down at the top of the bag and therefore it makes more sense to take down from the base and place it in the top of the bag.