Spray Foam vs. Fiberglass: Two Insulations Duke it Out for Champs Status (Part 4)

If you've been following along, we've been discussing spray foam and fiberglass insulation, specifically which one is better value for money. We've already mentioned that there's no clear-cut answer to that because the two types of insulation can't be compared, which we discussed briefly in our introduction.

In Round One, we discussed how fiberglass is a decent insulator, but doesn't do much to combat air leakage. As you know, eliminating air flow is crucial to a building’s overall energy efficiency and creating a high-quality building envelope. (If you need a refresher, you can read it here.)

In Round Two, we discussed how closed-cell spray foam is an insulator AND air barrier. That's a significant advantage over fiberglass, which you can read about here.

That being said, let's move on to today's post.

ROUND THREE: The Price Comparison

So when faced with the inevitable question, “Is spray foam more expensive than fiberglass?” we always say, “Well, yes, of course.” That’s because spray foam offers additional benefits that fiberglass can’t. Wouldn’t you expect to pay more for a product that offers more benefits? It’s like asking if a car with power windows is more expensive than a car with manual crank windows. Unless the car with manual windows has other amenities not available in the car with power windows, the power window car will be more expensive.

So how much more expensive is spray foam over fiberglass? Usually about twice as much. That’s a hard pill to swallow for a lot of people on a tight budget, or otherwise fearful of outlaying twice as much money upfront for a product they’ll probably never see. But it’s important to keep this in mind: spray foam is a permanent once-and-done insulation, so while you’re paying more upfront for it, it’ll last the lifetime of your building and will never need to be updated. Plus, the money you pay upfront will come back to you over time in the form of a less expensive utility bill every month. Remember that spray foam is an air barrier, so the 40-50% of your utility bill associated with air leakage will be eliminated. That’s a huge bonus compared to traditional fiberglass insulation.

So in the battle of spray foam vs. fiberglass, fiberglass still has a place in the market for its inexpensive ability to insulate quickly (yet not permanently). But if you’re looking for a product that offers more, in the form of air leakage protection and increased savings on utility bills, spray foam is the champ.