R value: What does it stand for?
What does R value measurement stand for? Like many of us, you have probably encountered different R values marked on insulation products packaging or you at least heard your contractor or insulating products manufacturer bragging about certain insulating materials high R values, without even asking yourself what does it mean, what does “R” stands for. Well, we believe that it is very important to know your insulation, without any high expectations of you becoming an expert in insulating your home, which is neither likely or necessary. Still, there are some basics that you should be aware of when choosing and installing insulation, which can not only make your choice easier but also help you make the right decision.
R value is a thermal resistance measurement used in building and construction to calculate and determine the thermal resistance, that is how well does certain (insulation) material resists the heat transfer. It is used to determine specific insulating product thermal performance, regardless of its acoustic and sound insulating properties, by using a simple formula expressed as m2xK\W. Here, m2 presents size measurement unit of the insulating material, K stands for the difference in temperature through the material, expressed in Kelvin and finally W presents the amount of heat that passes through the material, in watts. Simply put, R value measurements are calculated by simply dividing the thickness of the material with its thermal conductivity, or as previously explained, the amount of heat that flows through the insulating material.
As you are probably aware, the higher the R value, the better thermal performance of the insulation material. On the other hand, bear in mind that R values are reciprocal or inversed to so called U values which present the coefficient of the overall heat transfer and show how well the insulating material conducts heat, under some standard conditions, like certain temperature, humidity and wind. Properly understanding the given equation implies that high R values are good, just as low U values are good, so it is another thing to consider when purchasing your insulation material. Also bear in mind that there is a difference between added R value, which presents the thermal performance of the material itself and the overall R value, which measures the total thermal resistance of a building or a certain part and includes the added R value and the R value measurements of the air spaces and building materials. There is another difference between bulk insulation that has its own added R value, depending on the density and thickness of the material and reflective insulation which has overall R value, when combined with the building material or given air space.
First of all, R value measurements depend on the insulating materials themselves, mostly on their thickness and thus the ability to resist heat transfer. There are some typical R values connected to insulating products and materials, where vacuum insulated panels usually have the highest R values, followed by phenolic foam insulation and polystyrene and polyurethane insulation to fiberglass and rock wool insulating products. In determination of the overall R values, the surfaces such as walls, floors or ceilings and their R value measurement is also taken into consideration. It will depend on the position of the surface, that is whether it is horizontal or vertical, on the direction of heat transfer (is it upward or downward) and finally is it an indoor or an outdoor surface. Commonly, indoor surfaces have higher R values than outdoor surface, while downward heat transfer direction on horizontal surfaces (such as flat ceilings) have higher thermal resistance than upward direction of heat transfer on horizontal surfaces or overall on vertical surfaces (like walls).
Now that you are aware and understand some basic terms and thermal resistance performances of insulating products, that is their R value measurement, it will be easy to choose some of the products made by leading manufacturers of insulating products today, available at InsulationShop.co.
This article was written byVladimir Golubovic, professional writer and SEO expert.