How do Mongolians live in yurts during the winter where sometimes the night temperature drops to -40°C (-40°F) in some places? They do this by insulating their yurts really well. In preparation of winter, they add another layer of felts on their yurts, making the total felt insulation about 5 cm (~2 inches). They also take other measures such as sealing the gap at the bottom of the lattice wall with earth and using thick felt for the skylight cover (“urkh”).
Felt is great natural insulator; it has very low heat transmission property. There are two types of heat transfer; conductive and convective. Felt reduces the conductive transfer. Imagine your put a piece of felt on a very hot surface. It will take quite a long until you finger feel the heat on the other side of the felt. Now, imagine the you put the reflective material used in modern yurt as the only insulation on the same surface. You will immediately feel the heat on your finger. This is because the reflective material is itself serves as heat conductor.
The reflective material reduces convective heat tranfer, it reflects the heat to back to its source. But its effieniency is greatly reduced when the material is put directly under the outer cover, made of PVC. The outer cover absorbs the heat from the sun and then the reflecive insulation transmits the heat through it to the inside. That is why modern yurts become extremely hot in the summer. Some described that it becomes so “hot enough to melt candles“.
At Original Yurts, we use both felt insulation and reflective insulation. The reflective insulation reduces the amount of heat coming from the sun by reflecting it back to outside, then the felt insulation reduces transmission of the remaining heat to the inside. This combination makes our yurts best in insulated in its class.
