## Why the jacket stops retaining heat The main task of a winter jacket is to maintain a layer of warm air between the body and the cold. When this layer is disrupted, even the warmest down jacket stops working. The reasons can vary: * compressed filling; * exposed areas of the body; * moisture; * lack of additional layers. ## Restore the volume of the filling Over time, both natural down and synthetic materials clump together. "Cold zones" form between them, through which heat escapes. What to do: * wash the jacket on a delicate cycle; * place 2–3 tennis balls in the drum; * regularly shake the down jacket during drying. This will help the filling become airy again and distribute evenly. ## Seal all "heat leaks" Sometimes the problem is not with the jacket itself, but with gaps through which the cold seeps inside. Check: * whether the collar fits tightly; * whether the hood covers the neck well; * whether there is cold air coming in from below; * whether there are gaps at the cuffs. Additionally, use the principle of layering and don’t forget about a hat, scarf (or buff), and warm gloves. ## Add an extra insulating layer In severe cold, a down jacket alone may not be enough. Manufacturers and sports brands offer special thermal insulation liners. This can be: * a thin insulated vest; * a lightweight inner jacket. Such a layer is worn under the main outerwear and significantly increases thermal insulation. ## Protect the jacket from moisture Even the warmest down jacket stops keeping you warm when it gets wet. Moisture destroys the air layer and "pulls" heat away. To avoid this: * treat the jacket with a water-repellent spray; * try not to stay under wet snow or rain for long; * dry the jacket immediately after it gets wet. ## What’s the conclusion If the jacket suddenly became "cold", don’t rush to replace it with a new one. Often, it is enough to restore the filling, block the cold, and protect the clothing from moisture — and it will start keeping you warm again even in severe frost.