A U-value is a numerical measurement of the amount of heat lost through a specific material. The higher the U-value is found to be, the more heat will tend to be escaping from one medium to another. So, it is apparent that these values are extremely important in determining the heating efficiency of a home.
The calculation of U-value insulation involves measuring the amount of heat lost through a square metre of a certain material (such as a window pane) for each degree of difference between the two sides. Notwithstanding these calculations, U-values will have a direct effect on the temperature inside of a home.
This value is particularly important when gauging the effectiveness of insulation; especially underneath the floors of a home. Not only does this material need to be able to withstand the physical loads placed upon it, there are other considerations that need to be taken into account.
One such instance is when the insulation between two different elements (between a floor and a wall, for example), fail to meet. Cavity walls are a common installation where this is the case. Where this gap exists, a substantial amount of heat can be lost. Thus, floor insulation boards need to be continued into the wall cavity so that the boards will overlap with the existing insulation. If this is accomplished and insulation boards of a necessary thickness and correspondingly low U-value are put in place, the heating costs of a home can be drastically reduced. Obviously, lower U-values will correspond with thicker boards.
It should be noted that differing U-values will be needed if an insulation board is found either above or below a ground bearing slab (of concrete, for example). There are numerous charts that professionals will utilise in determining the correct thickness and which U-value will offer the best thermal protection. So, it should be clear to see that while the type of insulating material is indeed important, the corresponding U-value insulation is just as critical to help save money on heating costs over time.