I assume you mean double thickness? It would be a lined curtain or drape. Some are lined with fabric, some are lined with an insulated material. Either one would help stop heat loss when closed.
The main reasons are they help insulate the house and reduce heat loss therefore saving energy. They also help with sound insulation.
Heat transfer through double glazed windows by way of radiation barely changes. Trapped air in the gap between the inner glass pane and the outer glass pane prevents heat loss and acts as an insulator.
Double glazing reduces heat loss in a house by creating a sealed space between two panes of glass that acts as an insulating barrier. This barrier helps to prevent heat transfer between the inside and outside of the house, resulting in less heat loss during cold weather. Additionally, some double glazing windows may also have a low-emissivity coating that further reduces heat loss by reflecting heat back into the room.
the loss of body heat when in the water.
The loss of body heat when in the water
Lined curtains will help keep out the elements to a certain point, if you have a light colored fabric then the heat and light from the sun will be reflected off, also if you keep the blinds closed then you can prevent alot of heat from escaping in the winter.
It insulates the window and keeps heat in.
reduce heat loss
The loss of body heat when in the water.
To reduce heat loss by radiation in a house, consider adding insulation to walls, ceilings, and floors. Installing double glazed windows or window films can also help minimize heat loss. Additionally, using draft stoppers for doors and windows and sealing any gaps or cracks will further prevent heat from escaping.
If a large roof is twice the area of a small roof and they are otherwise the same, the heat loss will be approximately double. If the large roof is twice as insulated as the small roof the heat loss will be similar.
Slows the loss of heat from the body's core