Insulation and Your Home's Thermal Barrier

Properly insulating you home will greatly reduce heating and cooling costs (which consumes over 50% of your home's overall energy usage on average) and will also make your home more comfortable.

How Insulation Works

Insulation provides your home a resistence to heat flow.  The more resistance your home has to heat flow, the lower your heating and cooling cost will be. 

Heat will flow from a warmer space to a cooler space naturally.  During the winter heat will try to flow from your heated conditioned space to attics, garages, and outdoors.  Heat flow can also move indirectly through interior walls, ceiling, and floors, any where thers is a difference in temperature.  During the summer, the heat will flow in reverse from outdoors, garages, and attics into your conditioned space, where your air conditioner is providing cool air.  Proper insulation will prevent the heat flow from affecting your comfort levels by preventing heat to come in during the summer and prevent it from going out during the winter.  It will also allow your heating and cooling equipment to work more efficiently because they will not have to run as long in order to maintain your ideal set temperatures.

Where to Insulate in a Home

When insulating a home it is best to start from the attic and move down to the foundation. 

1. Attic - Open attic, vaults, attic access hatches and doors, and knee/hot walls (walls that separate conditioned space from attic space).
2. Exterior Walls - Ambient walls and garage walls.
3. Frame Floors - Above garages, under bay windows, above unconditioned crawl spaces.
4. Foundations - Basement walls, conditioned crawl spaces, rim and band joists, and slab floor insulation.

**One of the most overlooked areas for insulation by contractors is the foundation walls.  There is so much misinformation and lack of understanding of new building science regarding of the benefits of insulating your basement properly we have created a page dedicated to ONLY foundation walls insulation.**

The R-Value of Insulation

R-Value indicated the resistance to heat flow of insulation.  The higher the R-value, the more effective the insulation.

                    R-10 Attic Insulation                        R-50 Attic Insulation

R-value depends on the the type of insulation, the material it's made of, the thickness, and the density.  To calculate the R-value of multilayered insulation you add together each of the individual layers (for example if you had R-13 batt insulation covered by R-19 blown insulation in your attic your overall attic R-value is R-32).  The more insulation you install in your home, the higher the R-value of your home and the better it resists heat flow.

The effectiveness of your insulation also depends how and where you install the insulation.  Insulation that is compressed will not provide its full R-value.  The overall R-value wall or ceiling will be a little different from the insulations R-value as well because of studs and joists in the wall and ceiling.  The heat can flow around the insulation through the studs and joists.  These are just some examples of why it is important to properly install insulation

The amount of insulation you need depends on your climate zone, the type of HVAC equipment you have, and the section of the home you want to insulate.  An energy audit from an AEA auditor will give you the best suggestions on where your home can benefit the most with insulation installation and the best R-value to insulate too.

Types of Insulation

Rolls and batts—or blankets—are flexible products made from mineral fibers, such as fiberglass and rock wool.

They are available in widths suited to standard spacings of wall studs and attic or floor joists: 2x4 walls can hold R-13 or R-15 batts; 2x6 walls can have R-19 or R-21 products.

Loose-fill insulation—usually made of fiberglass, rock wool, or cellulose in the form of loose fibers or fiber pellets, it should be blown into spaces using special pneumatic equipment. The blown-in material conforms readily to building cavities and attics. Therefore, loose-fill insulation is well suited for places where it is difficult to install other types of insulation.

Rigid foam insulation—foam insulation typically is more expensive than fiber insulation. But it's very effective in buildings with space limitations and where higher R-values are needed. Foam insulation R-values range from R-4 to R-6.5 per inch of thickness, which is up to 2 times greater than most other insulating materials of the same thickness.

Foam-in-place insulation—this type can be blown into walls and reduces air leakage, if blown into cracks, such as around window and door frames.