Upgrading your home with James Hardie siding is a smart investment in durability and curb appeal. But to get the most out of that investment, it’s important to consider what goes underneath the siding. The right insulation can significantly improve your home’s comfort, energy efficiency, and protection from Minnesota’s cold winters and humid summers. In this post, we’ll explain the best insulation options to use with James Hardie siding and help you choose the one that offers the best value and performance for your home.
Best Insulation for James Hardie Siding: Closed Cell Foam
Without question, the best insulation to pair with James Hardie siding is closed cell foam insulation. This type of insulation offers the highest level of performance for Minnesota homeowners.
Key Advantages of Closed Cell Foam:
- Air Sealing: Closed cell foam is excellent at sealing the home against air infiltration. That means fewer drafts and more consistent indoor temperatures.
- High R-Value: It delivers a high R-value per inch, which is especially valuable in older homes with 2×4 framing. You can achieve better insulation in tighter wall spaces.
This makes closed cell foam insulation ideal for our cold winters and hot summers—helping keep the outside air where it belongs and improving your home’s energy efficiency year-round.
Challenges of Installing Closed Cell Foam Insulation
As great as closed cell foam is, it’s not the easiest to install—and that’s something every homeowner should be aware of before deciding.
What Makes It Difficult?
To properly install closed cell foam:
- We must remove all the existing siding.
- Then we take off the sheathing underneath the siding.
- Only after that can we spray the foam insulation directly into the wall cavities from the outside.
This is a very intrusive process and not something that can be done quickly or cheaply. While it offers top-tier performance, it comes with a higher price tag and requires a more involved construction project.
Alternative Insulation Options
If closed cell foam isn’t in your budget or you’re looking for a less invasive approach, there are other insulation options that can still offer real benefits—especially for older homes.
Fiberglass Bat Insulation
One practical alternative is fiberglass bat insulation. This involves:
- Removing the sheathing,
- Then installing fiberglass batts into the wall cavities.
This is a great solution for older homes, especially those built before the 1950s, which often don’t have any insulation—or may even have old newspaper inside the walls. Upgrading to modern fiberglass helps reduce energy loss and improve comfort without going all-in on closed cell foam.
Fanfold Insulation: A Cautionary Note
Another product we sometimes see is fanfold insulation, typically around 3/8 of an inch thick and installed outside the sheathing.
But in our experience, fanfold:
- Doesn’t offer meaningful thermal performance.
- Adds cost without adding real value.
We view this more as a sales gimmick than a solution. It may sound impressive on paper, but it doesn’t deliver the energy savings many homeowners are hoping for. If someone’s recommending fanfold as the main insulation strategy, we suggest looking a little closer.
Benefits of Closed Cell Foam for Minnesota’s Cold Climate
Let’s circle back to what makes closed cell foam such a standout—especially here in Minnesota.
- It seals up your home tighter than any other option.
- It delivers the best R-value per inch, even in older 2×4 wall cavities.
- It helps keep cold air out in the winter and hot air out in the summer.
If your top priority is comfort and energy efficiency, and you’re planning a full exterior remodel, closed cell foam is absolutely the best insulation to pair with James Hardie siding.
In Summary
When it comes to insulation, every home is different—and so is every homeowner’s budget and goals. At Craftsman’s Choice, we’ll help you decide what makes the most sense for your home, whether that’s closed cell foam, fiberglass batts, or another proven option.
The key is making sure you’re not just putting new siding over old problems. Insulation matters—especially in Minnesota. Let us help you make the most of your James Hardie siding installation.
Contact us today to schedule a free consultation and learn how we can make your home more efficient and comfortable.
