Down insulation is generally warmer than synthetic insulation because down has a higher warmth-to-weight ratio and better insulating properties.
Both synthetic and down bags have very different qualities, strengths and weaknesses. Synthetic bags are less expensive to manufacture and therefore are normally cheaper to buy. When wet they are also less likely to lose their vital insulation properties, unlike down sleeping bags. Down bags are generally much warmer than their synthetic counterparts but great care must be taken to look after them. When they get wet they will lose a lot of their insulation properties. It is recommended to take them to a specialist cleaner rather than wash them in your machine. Often more expensive than synthetic bags, they also last a lot longer. Down works by the feathers building on the insulating layers being warmed by body heat. Both have differing qualities and can been seen here - http://www.outdoorleisure101.com/sleeping-bag-reviews
Acrylic is generally warmer than wool because it is a synthetic material that traps heat more effectively.
There are three main types of insulation used in jackets: down, synthetic, and fleece. Down insulation, made from duck or goose feathers, provides excellent warmth and is lightweight, but loses its insulating properties when wet. Synthetic insulation, made from polyester fibers, is more water-resistant and retains warmth when wet, but is usually heavier and less compressible than down. Fleece insulation, made from synthetic fibers, provides good warmth and breathability, but is less effective in wet conditions. The type of insulation used in a jacket affects its warmth, weight, breathability, and performance in different weather conditions.
Down traps a lot of air, and air is a good insulator.
A down sleeping bag is admittedly warmer but if you are going to be camping in conditions where your bag is exposed to water, it is definitely a better idea to buy a synthetic sleeping bag. This is a lot more waterproof and will dry a lot quicker than the down. It also compacts a lot better than down and it definitely lighter.
Synthetic insulated jackets offer lightweight warmth, quick-drying properties, and insulation even when wet. They are also more affordable and easier to care for than down jackets.
700 fill power down refers to the quality and loftiness of the down feathers used in a jacket. The higher the fill power number, the better the insulation and warmth retention of the jacket. A jacket with 700 fill power down will be warmer and more insulating than a jacket with a lower fill power.
Alpaca socks are generally warmer than wool socks because alpaca fibers are hollow, providing better insulation and trapping more heat.
There are comforters that are made with synthetic down.
Dogs typically have a higher body temperature than humans, so they may feel warmer in colder conditions. However, dogs also have fur coats that provide insulation, which can help them stay warm in colder temperatures.
it is a good thing i think R Value is the thermal resistance of a given material. The higher the R Value the more thermal resistance and the better the insulation. So, an R48 roof system is warmer than an R32 roof system. All insulation materials are rated by their R Value. An inch of rigid insulation has a higher R Value than an inch of fiberglass insulation. Check with the insulation manufacturer for the R Value.
A string vest can feel warmer than a cotton one because of the way it traps heat close to the body due to the open-knit design. This design creates pockets of air that act as insulation, helping to retain body heat. Cotton vests, on the other hand, may not provide the same level of insulation due to their denser weave.