Spray Foam vs Fiberglass: Which Insulation Is Right for Your Home?

Understanding the Basics: Spray Foam vs Fiberglass Insulation

Before we compare costs and performance, let's look at what each material actually is.

Fiberglass insulation comes in batts or rolls made from fine glass fibers. You've probably seen the pink or yellow fluffy material tucked between wall studs. It's been the go-to choice for decades because it's affordable and easy to install.

Spray foam insulation is a liquid that expands when applied. It fills gaps and cracks as it hardens into a solid barrier. There are two types: open-cell (lighter and more flexible) and closed-cell (denser and more rigid).

The key difference? Fiberglass sits between framing members, while spray foam actually sticks to surfaces and seals air leaks at the same time.

How Do Spray Foam and Fiberglass Compare on R-Value?

R-value measures how well insulation resists heat flow. Higher numbers mean better insulation.

Fiberglass batts typically offer R-3.2 to R-3.8 per inch. An R-19 batt (standard for walls) is about 6 inches thick.

Closed-cell spray foam delivers R-6 to R-7 per inch. That means you get twice the insulating power in half the space. Open-cell spray foam falls in between at R-3.5 to R-3.7 per inch.

For attics and crawl spaces in the Gouverneur area where space is tight, spray foam gives you more thermal protection without eating up headroom. Fiberglass works great when you have room to install thicker batts and don't need the air-sealing benefits.

Air Sealing: The Hidden Advantage

Here's where spray foam really shines.

Fiberglass insulation doesn't stop air movement. Cold air can still slip around the edges and through gaps in your walls. That's why builders often pair fiberglass with separate air sealing work using caulk and weatherstripping.

Spray foam acts as both insulation and an air barrier. When it expands, it fills every crack and crevice. This stops drafts before they start. In older homes with lots of air leaks, spray foam can dramatically cut your heating bills.

If you're insulating a newer, tightly-built home, fiberglass with proper air sealing might be all you need. For older houses or renovations where air leakage is a problem, spray foam often pays for itself faster.

Cost Comparison: What Should You Expect to Pay?

Let's talk numbers.

Fiberglass insulation costs between $0.50 and $1.50 per square foot installed. For a 1,000-square-foot attic, you're looking at $500 to $1,500 total.

Spray foam runs $1.50 to $3.50 per square foot for open-cell and $3 to $7 per square foot for closed-cell. That same attic could cost $1,500 to $7,000 depending on which type you choose.

Yes, spray foam costs more upfront. But consider the long-term savings. Better air sealing means lower energy bills month after month. Many homeowners near Gouverneur see their spray foam investment pay back within 5 to 10 years through reduced heating costs.

Your budget matters, but so do your home's specific needs. A drafty farmhouse benefits more from spray foam than a well-sealed ranch built in the 1990s.

Moisture Control and Durability

Moisture can make or break your insulation's performance.

Fiberglass absorbs water like a sponge. When it gets wet, it loses R-value and can develop mold. If you have a roof leak or condensation problem, wet fiberglass needs to be replaced. In humid crawl spaces or basements, this becomes a real concern.

Closed-cell spray foam resists moisture and actually adds structural strength to your walls. It won't sag or settle over time. Open-cell spray foam is vapor-permeable, which can be good or bad depending on your climate and wall assembly.

For basements and crawl spaces in our region, closed-cell spray foam offers peace of mind. For standard attic insulation where moisture isn't a major issue, fiberglass performs reliably for decades.

Installation: DIY or Professional?

Fiberglass is relatively DIY-friendly if you're handy and take proper safety precautions. You'll need gloves, a mask, and protective clothing because the fibers irritate skin and lungs. The material is forgiving—you can cut it to fit and work at your own pace.

Spray foam requires professional equipment and expertise. The chemicals need exact mixing ratios and proper application technique. Most homeowners hire a licensed insulation contractor for spray foam work. Done wrong, spray foam can create problems instead of solving them.

If you're comfortable with DIY projects and want to save money, fiberglass makes sense. For spray foam, the professional installation cost is built into most quotes. Learn more about our professional insulation services to ensure quality results.

Which Insulation Works Best for Different Areas?

Not every space in your home needs the same solution.

Attics: Both work well here. Fiberglass is the budget choice, while spray foam under the roof deck creates a conditioned attic space.

Walls: If you're opening walls during a remodel, either option works. For retrofitting closed walls, blown-in fiberglass or injection foam are your choices.

Basements and Crawl Spaces: Closed-cell spray foam wins for moisture resistance and performance. Fiberglass can work if moisture isn't a concern.

Rim Joists: Spray foam is ideal for these irregular spaces where air leakage is common. Fiberglass leaves gaps.

Think about each area's specific challenges. A comprehensive home insulation strategy often uses both materials where each performs best.

Environmental and Health Considerations

If sustainability matters to you, here's what to know.

Fiberglass contains 20% to 30% recycled glass. It doesn't off-gas after installation. Some people are sensitive to the airborne fibers during installation, but once it's in place and covered, there's no ongoing exposure.

Spray foam starts as petroleum-based chemicals. During application, it releases fumes that require ventilation. After it cures (usually 24 hours), it's considered inert. Modern formulations have improved, but some homeowners still have concerns about VOCs.

Both materials will keep your home comfortable and reduce energy consumption—which is the biggest environmental benefit of all. Lower heating bills mean less fossil fuel burned over decades.

Making Your Decision: Key Questions to Ask

Ready to choose? Consider these factors:

• What's your budget? Fiberglass costs less upfront, spray foam may save more long-term.

• How old is your home? Older homes with air leaks benefit more from spray foam.

• Where are you insulating? Basements and rim joists favor spray foam; open attics work fine with fiberglass.

• How long will you own the home? Spray foam's payback period matters if you're selling soon.

• Are you doing other renovations? Adding insulation during a remodel might justify spray foam's higher cost.

Still not sure? A professional energy assessment can identify your home's biggest energy losses and recommend the best insulation strategy. Contact our team for a free consultation and quote.

Frequently Asked Questions

Is spray foam worth the extra cost compared to fiberglass?

It depends on your situation. Spray foam delivers better air sealing and higher R-value per inch, which can significantly lower energy bills in drafty or older homes. If your home already has good air sealing and you're working with a tight budget, quality fiberglass installation performs well. Calculate your potential energy savings to see if the investment makes sense for your specific home.

Can I install fiberglass insulation myself or do I need a professional?

You can install fiberglass yourself if you're comfortable working in attics or crawl spaces. Wear protective gear including gloves, long sleeves, eye protection, and a respirator mask. Make sure batts fit snugly without gaps or compression, which reduces effectiveness. For spray foam, always hire a professional—the equipment and technique require specialized training and certification.

Which insulation is better for soundproofing in my home?

Both materials reduce noise, but in different ways. Dense-pack fiberglass or standard batts in walls dampen sound by absorbing vibrations. Closed-cell spray foam blocks sound transmission by creating an airtight seal. For interior walls between rooms, fiberglass is cost-effective and works well. For exterior walls or bonus rooms above garages, spray foam's air-sealing properties also block outdoor noise.

How long does each type of insulation last?

Fiberglass insulation can last 80 to 100 years if it stays dry and undisturbed. However, it can compress over time, especially in walls, which reduces R-value. Spray foam is extremely durable and maintains its performance for the life of your home—often 80+ years. It won't settle, sag, or degrade unless exposed to UV light or physical damage.

Will spray foam cause moisture problems in my walls?

When installed correctly, spray foam prevents moisture problems by stopping air leakage (the main source of moisture in walls). However, closed-cell spray foam creates a vapor barrier that changes how your wall assembly handles moisture. This is why professional installation matters—your contractor needs to understand your climate zone and existing wall construction to choose the right foam type and application method.

Ready to Upgrade Your Home's Insulation?

Choosing between spray foam and fiberglass insulation doesn't have to be complicated. Both materials have their place, and the right choice depends on your home's specific needs, your budget, and your long-term goals.

At Arctic Fox Insulation, we've helped hundreds of homeowners near Gouverneur make smart insulation decisions. We'll assess your home, explain your options honestly, and deliver professional installation that stands the test of time.

Contact us today to schedule a free estimate online. Let's make your home more comfortable and energy-efficient, no matter which insulation you choose.