Published By
High Performance Insulation editorial team
Published by the High Performance Insulation editorial team using current service standards, cited public guidance, and field-review notes from the crews and operations leaders who execute the work.
Field Review
Bayron Molina
Co-Owner / Operations Director
Reviewed for field execution, assembly fit, moisture management, and the install sequencing HPI uses on real jobs.
Bayron co-founded High Performance Insulation with his brother, Elvis, after spending the last 10 years in the spray foam industry. He is family-first, takes real pride in the craft, and on his off days you can usually find him at the park with his kids.
Meet the HPI teamImportant Note
Code, safety, and re-entry requirements still depend on the product data sheet, jobsite conditions, and the authority having jurisdiction. Final decisions should follow the approved assembly and current manufacturer instructions.
Review date: April 18, 2026
The best spray foam insulation is not one chemistry and not one internet hot take. It is the spray foam that fits the assembly, has the technical documentation to support the code path, and can be installed cleanly and consistently by the crew spraying it.
What “best” really means on a real job
When builders ask about the best spray foam, they are usually asking four questions at once:
- Is this an open-cell job or a closed-cell job?
- Does the assembly need more R-value per inch or more full-cavity fill?
- Does the product have the documentation and support needed for the project?
- Can the crew produce a clean, dependable result with it?
That is the standard HPI uses, because the best spray foam on paper is not automatically the best spray foam on the wall or roof deck.
Start with the assembly, not the brand argument
| Assembly | Usually best spray foam path | Why |
|---|---|---|
| Unvented attic roof deck | Open-cell in many cases | Strong air sealing and full-cavity fill in deeper roof framing |
| Rim joists | Closed-cell | Higher R-value per inch in a shallow, leakage-prone area |
| Crawl-space walls | Closed-cell in many cases | Denser coverage and stronger moisture resistance |
| Garage ceilings and shallow framing | Closed-cell | Better thermal performance per inch |
| Selected wall packages | Open-cell or mixed system | Depends on cavity depth, budget, and wall strategy |
| Interior sound-softening applications | Open-cell | Better fit when full-cavity fill matters more than per-inch R-value |
That is why “best spray foam” is really a decision tree, not a single product pitch.
Why HPI uses Accufoam AF1 and Accufoam CC
HPI’s answer is grounded in the products we actually install.
- We use Accufoam AF1 for open-cell applications.
- We use Accufoam CC for closed-cell applications.
That does not mean we are claiming those are the only acceptable products in the market. It means those are the products we trust to meet our field standard.
The reasons are practical:
- published technical data we can price and build around
- a clear split between open-cell and closed-cell roles
- consistent manufacturer support
- product behavior our crews know how to execute well
The numbers matter, but they are not the whole answer
Accufoam publishes open-cell and closed-cell product data that shows why these two chemistries are chosen for different jobs.
- Accufoam’s open-cell product is built around full-cavity fill and air control.
- Accufoam’s closed-cell product publishes roughly R-7.5 at 1 inch, which matters when the assembly is short on depth.
That is enough to make the point: “best” changes with the assembly.
When open-cell is the best spray foam
Open-cell is often the best choice when the project needs:
- conditioned attic performance
- strong air sealing across deeper framing
- full-cavity fill without chasing maximum R-value per inch
- a softer acoustic effect in the right assemblies
This is why open-cell often leads the roofline conversation in Middle Tennessee homes.
When closed-cell is the best spray foam
Closed-cell usually wins when the job needs:
- more R-value in less space
- denser coverage in small or awkward cavities
- stronger moisture resistance
- a better fit for rim areas, crawl spaces, garages, or other high-stress transitions
That is why closed-cell is not the “premium upgrade version of open-cell.” It is a different tool for different assemblies.
What HPI will not do
We will not tell a builder that one foam is best everywhere.
We will not recommend open-cell on a detail that really needs closed-cell performance just to save money.
We will not recommend closed-cell everywhere if open-cell or a mixed system is the smarter fit.
And we do not buy into the idea that the cheapest drum automatically creates the best project.
The practical HPI answer
If the question is “What is the best spray foam insulation for every job?” there is no honest single answer.
If the question is “What is the best spray foam for this attic, this crawl space, this rim joist, or this builder scope?” then the answer gets clear fast.
That is how HPI approaches it:
- open-cell where the assembly wants full-cavity air-sealed coverage
- closed-cell where the assembly needs more performance per inch and denser control
- product choice tied to execution quality, not only price
Related resources
- Closed-Cell vs Open-Cell Spray Foam
- Closed-Cell Spray Foam R-Value
- Benefits of Spray Foam Insulation
- Spray Foam Insulation Price Per Square Foot
References
Frequently Asked Questions
What is the best spray foam insulation?
The best spray foam insulation is the one that fits the assembly and can be installed to a consistently high standard. For HPI that usually means open-cell foam for many conditioned attic and full-cavity applications, and closed-cell foam where the job needs higher R-value per inch, denser coverage, or stronger moisture resistance.
Is open-cell or closed-cell spray foam better?
Neither is universally better. Open-cell is often the stronger choice for deeper rooflines, sound-softening value, and full-cavity fill. Closed-cell is often the stronger choice for rim joists, crawl-space walls, garages, and shallow framing where every inch of depth matters. The best answer depends on where the foam is going and what problem it is solving.
Why does HPI use Accufoam products?
HPI uses Accufoam because the product line supports the install standard we want on live jobs: clear technical data, predictable field behavior, product support, and a clean split between open-cell and closed-cell use cases. We are not calling one brand the best for every contractor. We are explaining the product standard we trust behind our own work.
Should the cheapest spray foam win?
Not if the project cares about workmanship, finished appearance, documentation, or long-term performance. The cheapest drum cost is not the same thing as the best installed result. Builders usually pay for the bad decision later through cleanup issues, inconsistent coverage, schedule drag, or a weaker assembly than the plans actually called for.