If everything else is the same, an 800-filler on you will keep you hotter than a 650-filling, and it will compress a smaller size, which means you will have an easier time to insert it in a pocket or bag. Almost universally, a higher filling will cost more, and once you get up to 800- to 1,000 filling power, you will pay a few hundred dollars for everything you buy, whether it is a technical outdoor park, winter sleeping bag, or comfortable bed.
What about synthetic insulation?
Synthetic substitutes, such as PrimaloftDo not use filling power as a measurement. This makes it difficult to compare heat between two jackets.
One approach would be to find out the weight of insulation in the clothing, although manufacturers do not always reveal this information. Even if you reach a customer service to find the full weight, the comparison is discarded if the type of synthetic insulation differs from one clothing to the next. Primaloft -oro differs from primaloft array that differs even more from 3m unrestrained. Just not an easy metric to compare synthetic insulation, the way you can use filling power for goose.
Synthetic insulation does not compress as small as a goose, and it still does not match its heat. To make a synthetic jacket as hot as a down jacket, the manufacturer has to insert more insulation in it, making it more swollen and smarter. I buy goose down exclusively when I work at temperatures below 30 degrees Fahrenheit.