You’ve heard of insulation R-values, and you may have a general idea of what these numbers represent – but what do they really mean?
The purpose of insulation is to prevent heat from escaping your home in the winter and from entering in the summer. This helps reduce your need for heating and cooling which, in turn, saves energy and lowers your power bills. This also helps maintain a more consistent and comfortable environment in your home.
When considering the type of energy efficient insulation you want for your home, is the R-value sufficient to make an informed choice?
Get to Know the “R” in Insulation R-Values
In this context, the letter “R” stands for “resistance.” When used in terms of insulation products, the “R” represents how well the product resists heat flow based on the thickness of the material.
Theoretically, the higher the R-value, the less the material will conduct heat. In other words, it is a measure of conduction or conductivity.
Insulation R-values are assigned based on tests conducted in a lab setting. Unfortunately, the lab environment does not accurately simulate the conditions in your home. And that’s why you should never rely exclusively on a product’s R-value when making a material choice for your home.
How Does Insulation Work?
Because the purpose of insulation is to stop heat transfer, it sounds logical that R-values will tell you which products work best. However, heat does not flow exclusively through conduction.
Heat flow also involves radiation and convection.
Conduction is heat transfer through a material. Convection is heat transfer through gases and liquids. Radiation in this context describes electromagnetic heat transfer from the sun’s rays.
Insulation primarily works to block the conduction of heat and, to some extent, the convection of heat. It is not effective for blocking radiant heat. So, when you consider adding energy efficient features to your home, keep in mind that insulation alone cannot stop heat transfer.
Many types of insulation also cannot stop the heat transfer that occurs through the infiltration of air – although some products are especially effective for this purpose.
Choosing the Right Insulation R-Value for You
The most important takeaway from this discussion is that higher R-values will not necessarily make your home more energy efficient or comfortable.
The U.S. Department of Energy recommends total residential R-values based on what part of the country you live in. However, these recommendations tend to be overly general, and do not consider important factors such as the orientation of your home, shading and the influence of microclimates.
To determine the most appropriate insulation type and rating, consult a local energy efficiency and insulation contractor. A contractor that specializes in residential energy efficiency improvements can conduct an energy audit of your home and help you determine which improvements will best help you meet your goals.
GreenHome Specialties, serving customers in Layton, Provo and throughout northern Utah, provides home energy audits, energy efficient windows and insulation and duct sealing. Contact us today to learn more about making sense of insulation R-values.