What is the R-value?
When it comes to insulation, the R-value is very important and is mainly the first thing that you will need to consider.
The R-value represent the temperature resistance of the insulation material, meaning the ability to stop heat transfer. This means less cold air in the winter and more in the summer.
Adding multiple layers of insulation doesn’t increase the R-value, because it is measured in conducted heat.Ventilation is very important when you insulate your house.
If you have an old house you can use spray insulation. This is very effective as it has a higher R-value than most traditional insulators. You ca buy closed-cell insulation or open-cell. Open-cell insulation is used for attics to permit breathing.