There are many different metrics used to describe the level of warmth a sleep system will have. The mass market often uses an actual standardized temperature measurement with a heated mannequin. This technology is not all that accessible to the cottage industry, so we use other metrics. Often times the metrics used are vague, unexplained, or unreliable. Due to this I have made it a goal to provide as much information as I can to the consumer. Each variation of Timmermade sleep systems, when selected on the product page, will display a whole bunch of metrics. Here is an explanation of each one.
Total weight: This is the approximate finish weight of the item.
Total Fill weight: This is the approximate total amount of down fill that goes into the item. This is generally a very unreliable metric for comparing warmth between different products since different products have varying insulated areas.
Total insulated area: This is the total area of the portion of the sleep system that is insulated. So if you were to open up the whole system and lay it flat, excluding any un-insulated portions, this is the amount of area it covers. Different sleep systems are usually different sizes that result in different amounts of area. If you want to use total fill weight as a metric, you have to make sure the items being compared have a similar total insulated area.
Calculated Loft: Each chamber to be filled has a volume. Length x width x height (baffle). The fill that is put into that chamber has a volume. Length x width x height (calculated loft). If you multiply length x width x height, of the chamber, you get the chamber volume. If you multiply the chamber length x width x calculated loft this gives the height / loft of the fill if it were sitting in an open-top box, with those length and width dimensions. If you take that volume and divide by the fill power of the down to be put in, the result is the amount (ounces) of down in that defined area. If the consumer is provided with the fill power and the calculated loft (height), they now can know the exact amount of fill weight in their system, whether that be in a specific chamber, or in the whole item. They also know the exact density (overstuff) of the fill throughout the system. If you have a chamber volume of 210ci and fill volume of 523ci, you take 523 divided by 210, you get 2.5 and know your overstuff is 150%. It is a reliable metric for comparing warmth regardless of other variables like size, taper, features, or fill power.
Overstuff: This is a percentage of fill added over the amount needed to just barely fill a volume. It is added density. So if you have a chamber that is 210ci and you fill it with only enough fill to fill 210ci, that is 0% overstuff. 30% overstuff would be 210 x 1.3. A mistake often made is that 150% overstuff would be 210 x 1.5, but that is actually 50% overstuff. 210 is “1” in the formula. 150% overstuff would be 210 x 2.5.
Measured Loft: I do not currently have this metric listed because of the fairly recent fill changes that were made. I do not have the recorded data yet, but it is a very valuable metric that can be used regardless of size, taper, or features. It is the approximate measurement of the actual height space filled with down. It is taken at the baffle and in the middle of the chamber. This gives you an idea of the amount that the chamber puffs up between baffles. This number can vary depending on conditions and circumstances.
Fill Power: This is a test performed by down processors to measure how much volume a fill can fill so that manufacturers know how much to use in their chamber calculations. 900 fill power means that one ounce of that fill was capable of filling 900 cubic inches under the test conditiins. If fill power has any meaning to consumers, it only indicates weight. A fill that can fill more volume with less weight will result in a lighter weight item. The amount of insulation an item has is set by builder calculations, regardless of what fill power is used.
Measured Baffle Height: The above calculated the amount of down fill in the chambers. The height of the baffle between the shells is an indication of the amount of density that fill is held at.
Chamber Calculations: This is just a recap that fully explains the formula used to fill the chambers, which is area times calculated loft divided by fill power.