Insulation 101

If you’re going to put an addition on your home or perform any kind of remodeling, insulation has to be a topic you’re going to need to talk about. Today, insulation is one of the most technologically advanced products for your home and although you don’t see it, it’s so important in many ways.


If you don’t have the money to do your entire house, consider one area at a time. Even this has its downside because if you’re like everyone else, there’s always something else that comes up that you need the money for and pretty soon a few years have gone by and it’s still not done.

Here are some guidelines to help you when thinking about insulation. You can also check out insulation services by professionals.

Spray Foam Insulation

Liquid polyurethane is sprayed into the cavity of the wall, where it then hardens and transforms into a solid foam. Nothing beats spray foam for R-value and it has a soundproofing element as well which is pretty good!

Spray foam is largely for walls and cavities as well as attic ceilings.

Spray foam comes in two varieties: half-pound open-cell foam and a more dense type called two-pound closed-cell foam. Of the two, the two-pound variety does a better job at insulating but isn’t always the right choice for the job or the budget.

Closed-cell foam has the highest R-value of any insulator you can buy, up to R6 per inch. Wow! That’s amazing! Not only that, spray foam takes up much less space than fiberglass or comparable blown-in insulation and spray foam can save you as much as $500 a year in energy costs.

Blown-In Insulation

Blown-in insulation has been used for decades in homes all over the United States. It is usually made from a paper-like material known as white cellulose, which is usually processed from reclaimed and recycled newspapers, cardboard and so on. It works very well and has a higher than average R-value, depending on the depth blown.  The down side to blown in insulation is that if you use your attic for storage as most people do then you need to have a back up  plan for all you stored items.  This is usually a good time to clean it out as insulation is better then stuff you haven’t used for decades.

How it works: This is something you can do yourself if you’re so inclined. You can rent a mechanical blower from Home Depot or some other home improvement center. The blower comes with a hose that is attached to a corresponding box full of cellulose. All you have to do is point the hose where you want the insulation to go and fills the space. It’s pretty simple.

Types of blown-in insulation: Though there are several types of blown-in insulation available, the most common is a borate-treated Class I type called loose fill, consisting of pelleted cellulose.

Benefits of blown-in insulation: When packed densely into place, fire-proof cellulose loose fill insulates very well. It is also easily blown into tight places, further increasing the R-value (10″ = an R-value of 36). It is also moisture resistant, and the borate keeps insects and other vermin away from you walls and attic.

Cost: The average cost per square foot is between $0.64 – $1.19. So, for a 500 square foot area, your estimate will vary between $145 to $200, if you do it yourself. For a professional job, add between $150 to $300 for labor, and you’re looking at around $300 to $500 for 6 hours of work.

Reflective or Radiant Barrier

Usually installed in attics to reduce sweltering summer heat and insulate against winter cold, radiant barriers are perfect for reducing heating and cooling bills, while increasing your home’s R-value. Reflective barriers, though different in design, exact a similar principle in function.  These types of systems are usually used in much warmer climates then Wisconsin but they can be used here as well.

Insulating an Attic: Costs and Considerations

Estimates vary depending on the insulation type you choose and the area in which you live. For the most part, however, you’ll be looking at paying about $1,300 to $2,000total for the entire job.

Insulating Walls

Since most homeowners are seeking to insulate previously built structures with drywall, blown-in insulation works best in the interior. A simple hole is cut, insulation is blown in, and the hole is sealed, leaving the room warmer and more efficient, at about $1.00 per square foot. You can also insulate when finishing a wall’s rooms as well — particularly with basements and garages. This is when batt insulation is particularly useful.

What Does R-Value Mean?

R-value is a calculative method referring to thermal resistance. It is also a thermal measurement unit for particular materials in relation to how they insulate. A higher R-value means more heat resistance, which also means greater insulative qualities. All insulation products have an R-value associated with them so all you need to know is what R-value you need, based on where you live and what type of space you are insulating.  In general, those who live in Wisconsin need products with a higher R-value, while those in warmer climates need less R-value. To get a better idea of what your R-value should be, the Department of Energy recommends the following R-values for unfinished attics:

  • Hot climates: R-30
  • Temperate climates: R-38
  • Cold climates: R-49