How they differ
Both aim to keep your home comfortable and lower energy costs, but in different ways. Radiant barriers are thin reflective sheets in the attic or under the roof deck that reflect radiant heat from the sun. Spray foam expands to fill gaps and cracks in walls, ceilings and attics, creating an airtight seal.
Radiant barriers: how they work and when to use them
- Where: attics, under the roof deck or on rafters.
- Material: aluminum foil or reflective film.
- Best at: cutting heat gain on hot, sunny days.
- Cost: lower upfront than spray foam.
- Limits: doesn't stop air leaks or conductive heat.
A radiant barrier is a smart choice when your main concern is the sun beating on your roof. It works alongside existing insulation.
Spray foam: benefits and best uses
- Where: walls, ceilings, attics and crawl spaces.
- Material: polyurethane foam that hardens quickly.
- Does: insulates and air-seals in one step.
- Cost: higher upfront, with long-term savings.
- Extras: less dust and allergens; closed cell adds strength and blocks moisture.
Side by side
| Radiant barrier | Spray foam | |
|---|---|---|
| Main job | Reflects radiant heat | Insulates and seals air leaks |
| Where | Attic or roof deck | Walls, ceilings, attics, crawl spaces |
| Upfront cost | Lower | Higher |
| Energy savings | Moderate | High |
| Air sealing | No | Yes |
| Moisture barrier | No | Yes (closed cell) |
| Best for | Hot climates, existing insulation | A full insulation upgrade |
Installation tips
Radiant barrier
Leave an air gap for best performance, keep vents clear, and check now and then for damage or dust.
Spray foam
Use a professional installer, ventilate during application, and check for missed spots afterward.
Both need little maintenance once installed. Ask us about spray foam or reflective insulation for block walls.
*Savings vary based on your home, its current insulation, air leakage and energy use. Higher R-values mean greater insulating power.