When you insulate your home, picking the right insulation matters. It can greatly improve energy efficiency, comfort, and cost. Two of the most commonly used products are spray foam insulation and insulation batts. Both systems have the same main goal: keeping your indoor temperature stable and lowering energy bills. However, they work differently. They also vary in cost and the best places to use them.
Spray Foam Insulation vs Insulation Batts
Spray foam insulation is a two-part liquid chemical that expands on contact to form a hardened foam. It can fill cavities, cracks, and hard-to-reach spaces that would be difficult for batts to cover properly.
Two types of spray foam insulation exist:
- Open cell Foam: Softer, more flexible, with good soundproofing properties.
- Closed cell Foam: Denser, rigid, and offers higher insulation values and moisture resistance.
Trained professionals always apply it using specialized equipment.
Insulation batts are pre-cut slabs of material, typically made from fibreglass, rockwool (mineral wool). Install them between timber studs, joists, and rafters, and use them widely for insulating walls, ceilings, and under floors.
They’re popular because they’re affordable, widely available, and relatively easy to install—even for DIYers. You can find batts in a variety of R-values, making them suited for both retrofits and new builds.
1. Performance
Performance includes how well the insulation resists heat transfer, reduces drafts, and supports energy efficiency.
- Spray Foam Insulation: Closed-cell foam provides superior insulating power per inch, with R-values around R6.0 to R7.0. It also creates an effective air and vapour barrier, which helps eliminate energy-wasting drafts.
- Insulation Batts: Generally provide R-values from R2.0 to R6.0 depending on material and thickness. However, improper installation or leaving gaps around framing can cause performance to drop.
✅ Winner: Spray Foam – Excellent for sealing air leaks and maximising energy efficiency.
2. Air Sealing
- Spray Foam: Expands into crevices and hard-to-reach corners, creating an airtight seal. Ideal for rim joists, crawlspaces, and uneven framing.
- Insulation Batts: Avoid sealing air leaks. Any small gap or poor fit can compromise effectiveness and allow airflow through the structure.
✅ Winner: Spray Foam – Seals and insulates simultaneously.
3. Moisture Resistance
- Spray Foam: Closed-cell foam prevents water infiltration. It can also work as a vapor barrier. This makes it great for wet areas like basements.
- Insulation Batts: Fibreglass and rockwool batts can absorb moisture if exposed, reducing their insulating properties and encouraging mould growth.
✅ Winner: Spray Foam – Highly resistant to moisture and condensation.
4. Soundproofing
- Spray Foam: Open-cell foam is excellent for sound absorption, ideal for interior walls and ceilings.
- Insulation batts: made of Rockwool provide premium acoustic performance, and people often use them in home theatres and bedrooms.
✅ Draw – Both perform well for noise reduction depending on the type.
5. Safety
- Spray Foam: Fire-retardant additives are in most products. However, they still need a thermal barrier, like plasterboard, to meet building codes. Improper installation can also lead to off-gassing or poor air quality during curing.
- Insulation Batts: Glasswool insulation are naturally non-combustible, making them an excellent choice for fire-prone areas. They are also low-emission and safe when installed correctly.
✅ Winner: Insulation Batts – Better fire resistance and safer for DIYers.
6. Installation
- Spray Foam: Installation requires professionals because of the equipment and chemicals used. The process is more time-intensive and may require temporary evacuation.
- Insulation Batts: Easy to install with minimal tools—perfect for DIY projects or quick retrofits.
✅ Winner: Insulation Batts – Simple and accessible for most homeowners.
7. Cost
- Spray Foam: initially costs more, typically 2 to 3 times the price of batts. However, it can lower energy bills over time because it is more efficient.
- Insulation Batts: Affordable and widely available. Ideal for large-scale projects or cost-conscious renovations.
✅ Winner: Insulation Batts – Budget-friendly and effective for standard builds.
8. Sustainability
- Spray Foam: Energy savings from air sealing and thermal resistance can lower your carbon footprint long-term. However, production involves petrochemicals and the application process generates VOCs.
- Insulation Batts: Many brands sell batts made from recycled glass, wool, or natural fibers. They are a great eco-friendly choice. They’re also recyclable and low in chemical emissions.
✅ Winner: Insulation Batts – More environmentally friendly, especially natural fibre or recycled-content products.
When Should You Use Spray Foam Insulation?
Spray foam is ideal for:
- Residences in harsh weather conditions (extremely hot or cold).
- Hard-to-insulate areas like rim joists, crawlspaces, or vaulted ceilings.
- Projects that demand maximum energy efficiency.
- Areas with high moisture exposure or risk of condensation.
When Should You Use Insulation Batts?
Insulation batts are the better choice for:
- Projects on a tight budget.
- Standard wall and ceiling cavities in new homes or renovations.
- DIY applications or quick installation timelines.
- Homes that need fire-resistant or eco-conscious materials.
Final Verdict
Both insulation batts and spray foam offer valuable benefits, and the better choice ultimately depends on your specific needs. Your decision will depend on several factors. These include your budget, the climate where you live, and your home’s design. You should also consider whether to do it yourself or hire a professional.
In many cases, using both types can give the best results. For example, use spray foam in tight or damp areas like attics or crawlspaces. Utilize batts such as earthwool batts in accessible wall and ceiling areas for economical insulation coverage.