Is your home always too hot or too cold? Before you think about replacing your central air, or heating/cooling system, consider replacing your insulation. A properly insulated home can make you far less dependent on heating and cooling systems, by reducing unwanted heat loss or gain. In addition to a more comfortable climate, you may also benefit from reduced noise from outside by upgrading your insulation.
Replacing your insulation is fairly easy, but does require a bit of detective work before you get started. If your home is newly built, you should be able to get the insulation info from the builder. If your home is older, an energy auditor can determine what changes should be made, or you can do it yourself. If you prefer the DIY route, you'll first want to find places in your home where the insulation is exposed. The best places to look would be basements or attics. You'll want to understand both the type of insulation you have, as well as the thickness.
When it comes to ratings, insulation is measured in what is called an R-value. That number specifies the thermal resistance of the insulation. A higher number means more resistance and not all homes need the same rating. The R-value you need should be based on the climates of your area. The US Department of Energy provides an online tool to determine the suggested R-value your home should use.
There are a handful of different types of insulation, but they all serve the same purpose. Most people probably think of the pink "cotton candy" insulation, which is usually fiberglass. The most common types are batt, rolled, reflective, blown-in, or spray foam, and they all work in the same way. There are also insulations made specifically for soundproofing. Your home may actually use multiple types, depending on the location of what’s being insulated. The best way to figure out what type(s) you may need, is by talking to a local contractor.