Unlike your high school science teacher, I will try my best to keep you all engaged in this quick lesson.
It has been determined, and I am sure you all remember this: Energy cannot be created or destroyed but it can change phases, such as a gas to a liquid, and be transferred from one mass to another. This is also known as the Law of Conservation of Energy (if you want to get fancy).
Heat is a form of energy, also known as thermal energy. Thermal energy, put simply, is part of the total potential energy of an object, or a mass, that results in overall temperature. As masses change phases heat is either acquired or lost by the system as a whole.
In regards to temperature heat wants to flow from one object, or mass, to another in order for temperature to be stabilized. For example, we all know that when you fill your tub with hot and cold water it will be lukewarm, it will not just be hot or cold. The water reaches a uniform temperature due to conduction.
What is conduction?
Good thing I have done my research because I was definitely not paying attention during any of my science classes.
Conduction is the most familiar method of heat transfer. Heat is always transferred from one warmer mass to the colder mass when conduction is involved. Uniform temperature is always desired.
In regards to your HVAC system proper insulation of your home will ensure that a certain desired temperature is maintained while heat is neither lost or gained. When heat is lost or gained your system is using more energy than it should be in order to make sure that you are comfortable in your own home.
How Does Insulation Work?
Now that we all know that heat flows from warmer to cooler temperatures until there is no longer a difference in temperature, it is time to talk about heat transfer in regards to your heating and/or air conditioning system.
In the winter your HVAC system works to provide you with heat. The heat maintained within your home wants to go outside so that there is no temperature difference. The heat your home looses in the winter is gained by the heating system. In the summer the heat from the outside wants to make its way into your cool home. The heat gained from the outside is removed from you home by your air conditioning system. Your HVAC system works in order to make sure that you are comfortable but heat will always be obnoxious and want to kill your vibe.
Insulation provides resistance to the flow of heat. It is important to your home in order to make sure that energy is not being wasted by your HVAC system. The bulky light weight materials that make up insulation not only allow your HVAC system to function more efficiently but insulation also provides you with a more comfortable environment by controlling the amount of heat that is lost and/or gained by your home.