Why don't insulators need a high specific heat?

I want to conclude that the higher the specific heat the substance has, the better the insulator it can be...I have the evidence, can I safely make that conclusion?

1 Answer
Feb 26, 2018

Insulating ability depends mostly on the low thermal conductivity of the material.


I'm not an expert on this, but I've been starting to study it recently, so I'm sorry if this answer is wrong.

My understanding is that its more important to have a low thermal conductivity than a high specific heat. Thermal conductivity is the material's ability to allow heat to pass through (units are #"W"/"m K"#). Those with high thermal conductivity allow more energy to transfer through them, while those with low thermal conductivity allow less energy to transfer.

Thermal insulators are usually around 0.04 in terms of thermal conductivity, so they don't let heat travel through them.

Specific heat is important if you're thinking about how much the temperature of the insulator is changing. If it has a high specific heat it'll take a lot of energy to raise the temperature, and that can help a bit when it comes to insulation, but heat exchange and energy exchange is driven mostly by a temperature difference.

Take a house as an example, if you have a temperature of 70 degrees F in the house, and 10 degrees F outside, there is a large temperature difference, and so an energy exchange will want to occur there. The thermal conductivity of the walls is what slows it down in the end, rather than the high specific heat.

That's my understanding of it, sorry if I'm wrong though.