Insulation terms can be quite confusing to anyone outside the industry. If you’ve ever bought insulation for your house, you know that insulation with a high R factor is better. But what, exactly, does that mean? Did you know that the R value depends on other factors?

When it comes to buying more specific insulation products like removable insulation jackets for pipes, understanding the particulars of the three measures of insulation is key.

The K Factor
In order to understand the well-known R factor, it is important to understand the factors upon which it relies. The textbook definition of the K factor is “The time rate of steady heat flow through a unit area of homogeneous material induced by a unit temperature gradient in a direction perpendicular to that unit area.” That’s a mouthful.

Simplified, the K factor is the measure of heat that passes through one square foot of material that is 1 inch thick in an hour. Usually, insulation materials have a K Factor of less than 1. The lower the K value, the better the insulation.

The C Factor
C Factor stands for Thermal Conductance Factor. It’s the quantity of heat, measured in Btus, that passes through a foot of insulation material. Mathematically, it’s the K-factor divided by the thickness of the insulation material. Just like the K Factor, the lower the C factor, the better the insulating properties of the material.

The R Factor
Anyone who purchased insulation for their home knows what the R-factor is. It’s the number on the outside of the ungainly roll of itchy stuff. However, unbeknownst to most, the R-factor is not constant. It is the Thermal Resistance factor of insulation. In layman’s terms, this refers to the effectiveness of the insulation at retarding the transfer of heat.

The R factor is a variable value that measures the ability of a material to block heat rather than radiate it. The variable is the C factor. Mathematically, the R factor can be determined by R=1/C. The higher the R factor, the better the insulation.

The R factor basically pulls together all the information of the other factors and makes it easy to judge the effectiveness of insulating material. Keep in mind that these factors are specific to the materials being measured. For instance, if you take two pieces of batting that are rated at R 11 and put them together, you won’t get R 22 coverage. Understanding the ins and outs of the factors that help describe how effective insulation material is will go a long way to helping make the buying process easier.

William Jones has been in the heating and cooling industry for the past 37 years. Starting out in 1972 in the plumbing and heating industry, he obtained his Journeyman Plumbers license, then his Master Plumbers license and in Connecticut the P-1 unlimited Plumbing and Piping license. William studied Mechanical Engineering at the University of New Haven.

Being extremely interested in boilers and steam he then spent several years as a sales engineer concentrating on insulating steam systems and thermal efficiency. This experience in thermal efficiency led William to the point of being the foremost designer of reusable, removable insulation jackets in the United States. William is responsible for the design and specification of the Thermaxx LLC removable insulation covers.