We offer two types of insulation: down and synthetic.
Down insulation
Down is measured using a system called fill power. Fill power (fp) is a way of measuring how much space a given down type can fill. For example, 1 ounce of 850fp down will loft up to fill 850 cubic inches, and 1 ounce of 950fp can fill 950 cubic inches. (Picture is for illustrative purposes only.)
Since insulation works by trapping microscopic air pockets, a higher fill power can trap more air pockets per ounce. For use in a sleep system, this means that a higher fill power will provide the same insulation using fewer ounces of down. A 20°F rating is always 20°F, but a higher fill power quilt will be lighter. Enlightened Equipment uses Grey Duck Down (GDD) for our 850fp down, and Grey Goose Down (GGD) for our 950fp down.
Down quilts and sleeping bags are sewn with baffles, which are mesh walls that keep the down in place. Each temperature rating has a different size baffle so it can reach a particular loft height. The higher the loft, the more insulation the item provides.
You can figure out the loft of your down item by laying it flat and measuring how thick (or tall) your quilt or bag is. We use the following target loft heights for each of our temperature ratings:
50°F - 1 inch
40°F - 1 1/2 inches
30°F - 2 inches
20°F - 2 1/2 inches
10°F - 3 inches
0°F - 3 1/2 inches
-10°F - 4 inches
One of down's advantages is its packability, as shown in the photo below.
30° Regular/Regular Enigma APEX (Blue) vs. 30° regular/regular down-insulated Enigma (black)
Synthetic insulation
We use Climashield APEX as our synthetic insulation. APEX is one of the lightest and most versatile synthetic insulations on the market today. Synthetic insulation is less compressible and heavier than down, but it performs better in warm and humid conditions because it doesn't succumb to migration or clumping like down. Our APEX options are also faster drying, easier to clean, and more affordable. Climashield APEX quilts don't have baffles, since the insulation is a continuous sheet. We also don't add any sewn-through seams, to prevent cold spots.
We use the following APEX weights of insulation per temperature rating. Approximate thicknesses are also listed to give you an idea.
50°F - 2.0 oz/yd², approx. .75 inch thick
40°F - 4.0 oz/yd², approx. 1 inch thick
30°F - 6.0 oz/yd², approx 1.25 inch thick
20°F - 8.0 oz/yd², approx. 1.5 inch thick
Synthetic material weights may vary +/- 10% due to production variances.