How Insulation Works

Insulation Works Through Heat Transfer

  • Heat and energy are the same thing
  • Heat transfer via conduction happens much faster in objects with tightly packed atoms, solids, than those with spread-out atoms, gasses.
  • Solid objects with pockets of air, like a down comforter or double-walled mug, can keep heat in or out of where we want it.
  • Energy moves from hotter (higher energy) objects to colder (lower energy) objects

Understanding the second law of thermodynamics is crucial in comprehending heat transfer and its relationship to insulation. This law highlights nature's inclination to normalize and balance energy levels, where energy and heat are inseparable concepts. Objects and atoms contain varying amounts of energy and heat, with heat transferring from higher to lower temperature objects. For instance, a hot stove will eventually heat up a pot and its water, exemplifying this principle. The rate of temperature change depends on factors such as heat transfer type and materials involved.

Understanding R-Value

R-value serves as a measure of a material's ability to resist temperature changes, indicating its thermal resistance. Commercial insulating materials like cellulose, fiberglass, and spray foam undergo testing and receive an R-value rating, reflecting their effectiveness in limiting heat transfer. While a higher R-value implies better insulation, it's important to note that factors such as doors, windows, studs, and air leakage also impact a building's resistance to heat loss or gain, making sealing an essential aspect of enhancing energy efficiency.

Determining The Best Location

Insulation’s ability to resist heat flow is dependent on where and how it’s installed. For instance, compressed insulation loses some of its projected R-value. R-value can also be a cumulative measurement, like weight. The R-value of an attic, wall, or crawlspace is different from the insulation itself the same way the weight of fifty people is different from the weight of each one but still measured with the same units (pounds). The insulation has a base R-value while an assembly of insulation also has an R-value that’s based on the density and thickness of the insulation in a given area.