Insulation for any home helps to keep the cold out during the winter months, while it keeps the heat within; also, acting in the opposite way during the summer months, keeping the outside heat-out while retaining the cold air within the home. Actually, insulation has even more uses and functions within a home. They are also used for sound proofing, and as a duct and pipe covering to prevent heat loss; additionally, your cold and unfinished basements' plumbing copper pipes, may also be covered with insulation sleeves to prevent them from bursting due to freezing in the winter.
The types and uses vary with the size and kinds of materials used within the homes construction. They can be used on walls, exterior and interior; underneath or in between flooring; under tiling; sandwiched in between concrete patio slabs; filling the cavities of brick and block; below concrete flooring; within a ceiling's rafters, used with built-up flat roofing; around windows and doors; and, behind the exterior cladding on your home. Diversity breeds function!
Focusing on exterior walls and above your ceilings, there are about a number of popular types of insulation that most homeowners use, and can affordably benefit from. The proper insulation can save the property owner hundreds of dollars per month in heat-loss savings, depending on the size of the home and how well insulated it is, or can be made to be.
Currently, still the most popular, fibreglass insulation is used both on the exterior walls, in between your wall studs, and then, this is covered and closed off with a plastic vapor barrier, sealing it tight; also, the same with the area above the ceilings; again with a sealed-in vapor barrier; providing a complete closed in barrier- the insulation, from the rest of the inside of the house! Fibreglass is affordable, insulates well, and can easily fit into most vacant cavities. Fibreglass is very flexible stuff!
Handling this type of insulation can become extremely itchy and irritate your skin; so, any DIY's need to wear protective clothing and gloves, goggles, and a good quality breathing mask, when using either the loose or batt fibreglass insulation. Fibreglass is a similar cousin to asbestos, and works the same way on your lungs!
Next, we have Rock wool, which similar to fibreglass; but, more expensive and doesn't cause the same itchy reaction. Yet, still needs caution and protection to work with. It can be compared to dryer lint that can be dusty when handled. Rock wool also comes in loose fill that can be blown in or poured out of bags, making it easy to fill any needed space.
R factor is an important consideration in the value of insulations' energy saving ability. Expert opinion states that, "Fibreglass offers an R-value of 2.2 to 2.7 per inch, while Rock wool has an R-value of 3.0 to 3.3 per inch, making it a slightly better insulator than fibreglass"; according to the U.S. Department of Energy! Rock wool is also highly fire rated.
Then there is cellulose or blown in insulation; which is an organic, loose-fill material made mostly from recycled paper products. This insulation is usually chemically treated to resist attack from moisture and pests. Water or moisture absorption will make cellulose heavier, making it become compacted and lose its insulation value. Not a good idea to use it in the attic under a leaking roof!