Shelter is one of the basic needs of human existence, along with food, water and oxygen. One of the biggest benefits of adequate shelter is that is helps to maintain the right temperature, keeping the body at its optimum temperature and providing comfort. While we think of heating and cooling as the two processes that maintain this comfort, the truth is that heat is the essential element. Heat is a form of energy, while cool is simply the absence of heat. Understanding heat is one way to get a good understanding of how to insulate your home.
Second Law of Thermodynamics
The second law of thermodynamics describes the way that heat transfers between substances. At the basic level it works like this: where two or more substances (solid, gas or liquid) meet, the heat will work to distribute as evenly as possible between the substances, with heat moving from the warmest substance, into the others, raising their temperatures as the warmest substance cools. This process continues until all substances are the same temperature, or until your thermostat kicks off, whichever happens first!
Two still substances that reside side by side will transfer heat directly. Energy, in the form of heat moves from the warmest substance to cooler substances, traveling directly from one to the other in an attempt to create equilibrium. Some substances change temperature more slowly than others. Conduction can be controlled by placing barriers, or space, between substances to slow the conduction process, keeping heat in or out, whichever you desire.
Moving air, gasses, and liquids will transfer heat to or from surrounding substances, by convection as it moves. If the air or liquid is cooler than surrounding substances, as it moves past the surrounding substances, it will warm, by absorbing heat as it goes, and vice versa. Thermal convection is the process used by forced air heat systems, raising the temperature of walls, floors, furniture and other objects in your home, to warm the space.
Radiation is how heat travels through gas or air that is not moving. The heat moves in a wave form, working on surrounding surfaces to equalize the temperatures. Radiant heat is how most heat starts. Heating elements, flames and heated substances, such as stone, radiate heat into the surrounding gases and other substances. The main source of radiant heat on our planet is the sun.
Insulation works to slow the process of heat transfer between substances. Differing substances transfer heat at varying rates. the speed at which heat travels is measured in “R” factor. The higher the “R” factor, the slower heat transfers through the substance. Insulation is made to suit a lot of variables. Radiant barriers and batting cover large areas like ceilings and walls. Aerosol foam and caulking insulate by preventing “convection” transfer by sealing out air. To learn more about the insulation you need, leave a question in the comments.