It saves your time lapse photos in-app (rather than to your camera roll) for you to export to the location of your choice: your photo library (as individual photos), the Glimpse Cloud, or SyncDocs. The latter two store your photos as movies/glimpses; they are free but do require you to have an account.
Insulation works by reducing the transfer of heat by means of a barrier. Unfortunately in most cases the better the insulation the more it costs, so like most things a balancing act is required. To understand insulation you need to know what thermal conductivity, R values and U values are. Thermal conductivity is the measure of how easily heat flows through a specific type of material, regardless of the thickness of the material. The lower the thermal conductivity of a material, the better the thermal performance (i.e. the slower heat will move across a material). See below for some example materials and there conductivity values.
List of thermal conductivities. In heat transfer, the thermal conductivity of a substance, k, is an intensive property that indicates its ability to conduct heat. Thermal conductivity is often measured with laser flash analysis. Alternative measurements are also established. Mixtures may have variable thermal conductivities due to composition.