Let’s settle this once and for all: is fiberglass still a smart choice, or has spray foam completely taken over?
If you’re still using fiberglass in 2025, it’s kind of like showing up to a Tesla dealership asking for a horse. Fiberglass was fine back in the day. It was cheap, easy to install, and better than nothing. But these days? It just doesn’t hold up.
The problem with fiberglass is gaps — gaps in your walls, gaps in coverage, and gaps in performance. It doesn’t seal anything. It just sits there. Air still moves around it. Moisture still gets through. And rodents? Oh, they love it. It’s basically a rent-free mattress for mice.
Spray foam is a completely different animal. It expands on contact, fills every crack and weird corner, and creates an airtight seal that locks in comfort and keeps out moisture, air leaks, and bugs. It acts like a thermal blanket and a moisture barrier in one.
Then there’s the performance over time. Fiberglass sags, shifts, and settles. After a few years, it’s not doing much. Spray foam? It stays locked in place for the life of the structure. That means one install can give you 20+ years of consistent energy savings.
And here’s the kicker — spray foam also improves the structure itself. Closed-cell foam actually strengthens your walls. Fiberglass can’t even hold itself up half the time.
Yes, spray foam costs more up front. But over time? It wins in savings, comfort, air quality, noise control, and resale value. It’s not even close.
If you’re building new or upgrading an old space, you’ve got to think long-term. Don’t throw money at a cheaper option that’ll underperform for decades. Spray foam once — and be done.
