When it comes to insulating exterior walls for any building the old adage is still very true. You’re only as strong as your weakest link, and for the exterior wall that is the windows.

For a residential home, you can basically divide the exterior wall insulation into 3 sections: chamber, framing, windows.  We can talk all day long about how we can improve wall insulation, but I don’t know too many exterior walls in a home that doesn’t have a window in that exterior wall.  In my home that would be 2 walls total that have no windows.

Most people are very surprised to find out that a double pane low e insulated glass window, the most popular window installed in homes today has an R-value rating of 2. That’s right, 2. To really improve the exterior wall insulation of a home you need upgrade to a R4 triple pane window. That doubles the value of the weakest insulation point of the exterior wall section, which can easily be 10-20%.

This is where the EcoSmart™ Stud (ESS) becomes a essential part of the equation. Since the ESS is much less expensive way to increase the insulation value of the framing compared to continuous insulation (CI), we can upgrade the window insulation also! This how we get a 50-70% reduction in HVAC energy needs by upgrading the chamber, framing, and window insulation simultaneously. For less money than CI insulation alone!

Let’s put some numbers to that. 

These R-value figures are for a 16 ft framed wall section with windows that are 10% of the wall section. Effective insulation is the calculated overall value of the different R-values from the chamber, framing, and windows.

• Base: 2×6 framing, fiberglass batts, double pane window = R-8.65 effective insulation
• Upgrade #1: R20+7.5CI wall section with double pane window = R-11.2 effective insulation
• Upgrade #2: 2×6 ESS wall section triple pane window = R-14.25 effective insulation.
• Upgrade #3: 2×8 ESS wall section triple pane window = R-19.2 effective insulation

Now let’s translate this into an actual home build.  Part of this information is based on actual bids on a 2240 sq ft 2018 new home build.

• 2×6 framing, R-60 attic, R-20 fiberglass batts, Double pane windows. Base cost-$
• R20+7.5CI wall build with double pane windows. Adding up all extra and labor and materials cost. Upgrade cost $11,500
• 2×6 ESS wall build: $1280 extra for 2×6 ESS, insulation upgrade $2500, Triple pane windows $2200. Upgrade cost $5980.
• 2×8 ESS wall build: $2240 extra for 2×8 ESS, insulation upgrade $3500, Triple pane windows $2200. Upgrade cost $7940

The 2×6 and 2×8 ESS walls get you a better effective wall insulation with the triple pane windows at less cost than the R20+7.5CI wall upgrade alone! Better effective insulation equals lower energy bills, and less CO₂ going into the atmosphere.

EcoSmart Stud exterior walls are a stronger, more resilient Composite Walls to boot!