Drill and Fill Insulation: A Smart Way to Upgrade Your Home’s Efficiency
- Mei-Lin Arora
- 7 days ago
- 3 min read
Updated: 5 days ago
If your house feels drafty in the winter and sweltering in the summer, it might not be your HVAC system—it could be your walls. Drill and fill insulation is one of the easiest ways to upgrade older homes without tearing down drywall. By drilling small holes and injecting insulation directly into wall cavities, you can dramatically boost comfort and cut energy bills.
What is drill and fill insulation?
Drill and fill insulation is a retrofit method where contractors drill small holes in walls, then blow in or inject insulating material. Once filled, the holes are sealed, leaving your wall structure intact.
Think of it as a “minimally invasive surgery” for your home’s thermal performance—fast, effective, and budget-friendly.
This method works especially well for homes built before modern insulation standards, where wall cavities are often empty.
Drill and fill insulation vs. other methods
When comparing insulation upgrades, homeowners often consider multiple options:
Foam insulation vs batt insulation – Spray foam or injected foam offers better air sealing than fiberglass batts, which can leave gaps.
In wall insulation foam – Expanding foam fills cracks and cavities more completely, reducing drafts.
Best duct insulation – Even with insulated walls, uninsulated ductwork can waste up to 30% of heated or cooled air, according to the U.S. Department of Energy.
Drill and fill doesn’t replace attic or duct insulation, but it fills a big gap—literally—by addressing uninsulated walls.
Drill and fill for block walls
One of the best uses for this method is cinder block insulation fill or core fill insulation in block walls. Block walls are notoriously inefficient because they act as thermal bridges, allowing heat and cold to pass easily. Filling the cores with foam or loose-fill insulation reduces this transfer.
The Building Science Corporation highlights that filled block walls can improve both energy efficiency and soundproofing, making them a win for homeowners.
Cost and benefits
The price of drill and fill insulation depends on material and wall type but usually runs $1.50–$3.00 per square foot. While that’s an upfront investment, it typically pays for itself in a few years through reduced energy bills.
Benefits include:
Lower heating and cooling costs
Better indoor comfort
Increased home value
Quick installation with minimal disruption
Most projects take less than a day, making it one of the fastest energy upgrades available.
FAQ
What is drill and fill insulation?
A retrofit method where insulation is injected into wall cavities through drilled holes.
Does drill and fill work on block walls?
Yes, it’s effective for cinder block insulation fill and core fill insulation in block walls.
Foam insulation vs batt insulation—what’s better?
Foam provides better coverage and air sealing, while batts are cheaper but less effective in retrofits.
Can I use in wall insulation foam for old homes?
Yes, it’s one of the best options since it fills gaps that fiberglass cannot.
What about the best duct insulation?
Walls are important, but ducts also need insulation to prevent energy loss.
Final verdict: worth the drill
If you’re looking for a non-invasive, cost-effective way to improve your home’s efficiency, drill and fill insulation is hard to beat. Whether you’re dealing with empty wall cavities, block walls, or just drafty rooms, it offers a quick path to comfort and savings 🔨🏡.
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