Is insulation the end all energy saver? In some climates, this is 100% yes, especially climates that need mostly heating, or climates that need tons of cooling. However, proper insulation selection requires an energy model in many cases. Please note that the purpose of this article is to illustrate the importance of energy-modeling and to get users to think about preconceived notions. (I’m sure I’ll get an email from an insulation manufacturer)

Let’s take a look at a climate such as Dallas, Texas:

Like many climates in the U.S.A., it requires mostly cooling, but requires a decent amount of heating. Many commercial buildings do not require any heating until the outdoor ambient temperature reaches 45 degrees F (due to heat coming in the windows, and heat from lights, people, pc’s etc.).

If the building temperature for cooling is 75 degrees, that means there is a 30 degree range - where insulation actually costs more energy (anytime the outdoor temperature is between 45-75 degrees F). In these cases, heat is actually “trapped” inside the building by the excess insulation (kind of like when you jam your entire extended family in a room on Christmas eve).

In a climate such as Dallas, weather data will show that over 4000 hours are between 45-75 degrees F. In other words,too much insulation in the walls is a potential problem for over 40% of the year.
Since that leaves 60% of the year remaining, we cannot simply ignore insulation. However, it means that over-insulating will more than likely result in a greater energy loss, depending on your buildings cooling and heating profile. Thus, there will be an optimum insulation level. In order to determine this optimum number, it is a good idea to use quick analysis software such as eQUEST. A good user can perform several runs in less than an hour. One could simply perform a run, and keep adding insulation, until the energy savings starts to decline. At that point, you will have found your optimum insulation amount

Energy-models are key to successful decisions. There is no possible way you could realize how much insulation is disadvantageous without performing an energy model.