Which Kind of Insulation is Best?

This is one of the most common questions homeowners want to know when considering an insulation project.

The answer? The best type for you depends on:

  • How much insulation is needed?
  • How accessible is the space that needs insulation?
  • How much space is available for the insulation?
  • What’s your budget?

Comparisons need to be based on R-value

Insulations are rated in terms of thermal resistance — R-value. The R-value tells you the resistance to heat flow.

The higher the R-value of an insulation, the greater its effectiveness. It depends on things like the type of material used, its thickness and its density. Some insulation is layered to give it a higher R-value.

It’s important to know that if insulation is compressed, it won’t give you its full rated R-value, such as when insulation batts rated for one thickness are squeezed into a thinner space.

R-value is also compromised when the insulation is exposed to air flow. Because of that, air sealing your attic is critical before adding or replacing insulation

Joists, studs and rafters in the project area will affect the R-value of the insulation too — in a ceiling for example. The insulation itself can’t prevent heat flow through those materials, so the R-value of the overall insulated area may be different from that of the insulation.

The R-value for Minnesota

It won’t surprise you that Minnesota’s R-value needs are among the highest in the nation because of our cold winters. No matter what heating system you use, they are:

  • R49-R60 for attics
  • R30-R60 for cathedral ceilings
  • Walls have two requirements: R13-R21 for cavities; R5-R6 for insulation sheathing
  • R25-R30 for floors

Don’t forget though — a properly insulated home or business is kept more comfortable all through the year. It helps keep the structure cooler in the summer as well as warmer in the winter.

Read the label

The Federal Trade Commission has clear rules about how R-values are labeled on insulation products for your home. Not only are the R-values clear, but also facts about health, safety and fire hazard issues.

You want to be sure you’re using a product that fits your situation, whether you do the job yourself or hire a contractor. Take time to read the labels before starting your project.

If you hire a professional, you can even ask them for the labels off the packages they’re using. Remember, an educated consumer is a wise consumer!

The different types of insulation

Some types of insulation can be installed yourself. Others need a professional with the proper equipment.

Consider the various types, their R-values and the thickness needed. The type you use for your project will depend on the spaces that need it. Insulation that works best for a ceiling isn’t the same as what works best in wall cavities, for example.

A combination of insulation types is usually the best solution, especially in new construction where all the spaces are open. In existing homes you won’t be able to access the wall cavities and other spaces that are closed off. But there are still many solutions a professional can suggest.

BLANKETS — These are flexible batts or rolls made from mineral fibers like fiberglass. The come in widths that fit the standard spacing builders use for walls, attics and floors.

If some of the areas aren’t standard, they need to be hand-cut to fit (not squeezed, as they’ll lose some of their R-value). This would include by windows and doors, around light or outlet boxes, etc.

BLOWN-IN — This is a loose fill insulation made from materials like cellulose or fiberglass. It needs to be blown in with pneumatic equipment and is great for filling wall cavities, around obstructions and other irregular spaces.
This is also used in new construction in walls when mixed with an adhesive, so it doesn’t settle down into the spaces.

FOAM — This is also a type of spray-in insulation, made up of either open- or closed-cell foams. The advantage of the open-cell is allowing water vapor to move through more easily (resisting mold). But it has a lower R-value than closed-cell, so isn’t always the best choice.

Insulations with the names polyicynene, polyisocyanurate and polyurethane are all types of spray-in foams.

RIGID — This type is fibrous materials or plastic foams that are formed into “boards” and pipe coverings. It’s often used for foundations and in wall sheathing.

REFLECTIVE — Some insulation is made from aluminum foils with backings like plastic film, kraft paper or cardboard. It’s most effective in reducing downward heat flow. They’re typically used between floor joists, roof rafters and wall studs.

If you’ve still got questions about which kind of insulation is best for your project, let us know! 

We’d be happy to offer our recommendation and give you a free estimate.