Avkylningslag

Avkylningslag is a Swedish term that translates to cooling law. In common usage it can refer to two different concepts: a physical principle that describes how bodies lose heat, and a potential or proposed legal rule connected to the consumer right to withdraw from a purchase.

As a physical principle, avkylningslagen is most often identified with Newton's law of cooling. The law states that the rate of heat exchange between an object and its surroundings is proportional to the temperature difference between them. The typical form is dT/dt = -k(T - T_env), where k is a positive constant depending on material properties and the environment. Solutions show exponential approach to the ambient temperature, T(t) = T_env + (T0 - T_env) e^{-kt}. The law applies as an approximation under conditions of convective and radiative heat transfer and is widely used in engineering, physics and environmental modeling.

In Swedish legal discourse, avkylningslag can be used to describe, or be proposed as, a regulatory framework concerning cooling-off rights—allowing consumers to cancel purchases within a set period after receipt of goods or service. Such cooling-off provisions are usually part of broader distance-selling or consumer-protection statutes and vary by jurisdiction and context. The term is not a standard formal statute in Swedish law; in most contexts the physics sense dominates, while the legal sense remains more as a descriptor of consumer-protection concepts.