The science behind home insulation

July 15, 2016

For the average homeowner, insulation is all about keeping the home warm in the winter and cool in the summer. For some, there's also a basic understanding that a well insulated home will translate into energy efficiency and dollar savings on natural gas and electricity. But there's also science behind home insulation, and clear advantages in understanding how insulation works. Bottom line, it's all about heat flow (heat transfer), and specifically the three dynamics that affect heat flow: convection, conduction, and radiation. It all sounds overly scientific, but in general, air moves from warm to cool, and the three dynamics are the ones that affect air movement throughout a home. Convection is the dynamic where hot air rises, while cool air sinks. Here, home insulation will slow down this type of heat flow. Conduction is heat that moves through a specific material. Again, insulation will dramatically slow down this type of heat flow. Radiation is basically heat that travels in a direct straight line, heating up any solids in the way. Insulation reduces this dynamic. In any building structure, there's air movement - some of it desirable, some of it not. During winter, the idea is to prevent air movement in the form of heat loss. And although the heating system is designed to generate heat, losing that heat is clearly unproductive. In summer, when it's hot, the idea is to prevent warm air from creeping into the house, while stopping cooled indoor air from escaping. This is exactly where insulation will do its job - it effectively decreases heat flow (summer and winter) by creating resistance to air movement. For the most part, resistance to heat flow is measured as R-Value. This measurement pertains to all home insulation products, and defines the insulation's capacity to resist heat flow. Simply put, the higher the R-Value rating, the more effective the insulation product will be in doing its job. This, of course, is dependent on the type of insulation, and very dependent on the installation itself. While it may seem that loading up on product will deliver better performance, there is much more to the science of insulation than just product. There are a number of factors that will influence R-Value, beyond the number that's printed on the package. This is why proper installation is so critical, and why professional installers will do a much better job than amateurs. The experts understand the science behind the insulation, and therefore incorporate air sealing and ventilation into the overall installation. It becomes a "system" where sealing, insulation, and ventilation contribute to performance, allowing for R-Values to be maximized, and energy efficiencies to be optimized. For the average homeowner, it's important to understand the basics of home insulation - it makes for better decisions with respect to choosing product and deciding on installation methods. But choosing a competent insulation contractor will be the real key to success. Professionals understand the array of products on the market, and understand how best to suit the unique needs of the homeowner.