Both methods work. But in most Ontario homes, one reaches full coverage far more reliably than the other.
If you have been reading up on attic insulation, you have probably already run into the blow-in vs. batt question and come away with a half-answer. Most articles describe both methods neutrally and leave you to figure it out. That is not especially useful when you are standing in your attic, wondering why the upstairs is cold in January and hot in July.
At JN Roofing, we install blown-in attic insulation using Owens Corning ProPink L77 Loosefill. We have a point of view on why, and this article lays it out plainly. We will also tell you when batt insulation is the better choice, because in some attics, it genuinely is, and in those cases, you are better off hiring someone who specializes in batts rather than forcing the wrong approach.
What Is Blown-In Attic Insulation?
Blown-in insulation is a loose, fluffy material installed with a machine that blows it across your attic floor.
Because it is blown rather than hand-placed, the material flows around joists, pipes, wiring, and anything else in the way. There are no panels to cut and no edges to fit. It simply settles into every corner in one continuous layer. Once it is installed, the attic floor looks like an even blanket of insulation from wall to wall.
At JN Roofing, we install Owens Corning ProPink L77 Loosefill, a blown-in fibreglass made specifically for attics. Reaching R-60 takes roughly 22 inches of settled material across the attic floor. Because it flows into every gap, it is hard to end up with missed spots, which is exactly what you want if manufacturer warranty coverage, or simply long-term performance, matters to you.
Blown-in is the stronger choice for attics with:
- Uneven or non-standard framing
- Pipes, wiring, or blocking in the way
- Tight or awkward access points
- Existing insulation that just needs topping up rather than a full tear-out
- Older Ontario homes, which often have several of the above at once
In our experience across Barrie, Parry Sound, Muskoka, and Collingwood, most homes built before the 1990s fall into that last category. The framing is rarely neat, the wiring runs in unexpected places, and there is almost always some existing insulation that has settled or been disturbed over the years. Blown-in handles all of that gracefully.
What Is Batt Attic Insulation?
Batt insulation comes in pre-cut blanket panels, usually fibreglass or mineral wool, sized to fit between standard attic joists.
To reach R-60, an installer lays batts between the joists, then stacks a second layer crosswise on top so heat cannot escape straight through the wooden joists. Total depth usually ranges from 16 to 20 inches, depending on the specific product.
When installed carefully, batts perform just as well as blown-in. The important word is carefully. A batt that gets squished to fit, torn at the edges, or left with a gap at a joist intersection drops the real-world R-value well below what the label says. And unlike blown-in, the gaps are harder to spot after the job is done because the top layer covers them.
Batts are a strong choice for:
- Simple, rectangular attics with evenly spaced framing
- Attics with good overhead room for careful hand placement
- New builds or recent renovations with clean, unobstructed access
- Homes with no existing insulation that need to be worked around
If that describes your attic, a properly installed batt system can absolutely achieve R-60 performance. In those situations, we typically recommend hiring a contractor who specializes in batt insulation.
We believe in using the right solution for the right application, and we’re always happy to recommend a batt specialist when it’s the better fit for the job.
Where batts struggle is in older homes with complex framing, low clearance, or lots of obstructions. In those attics, batts almost always end up with gaps, and gaps are what quietly kill thermal performance.
Understanding R-Value and what it means
R-value measures how well insulation slows heat from moving through it. The higher the R-value, the better your attic holds heat in winter and keeps it out in summer. Attics are supposed to stay cold in the winter. So the point of the insulation is to have it keep the heat in your house, not the attic. In the summer, it is meant to keep the heat out of your house.
Every insulation product has a rated R-value per inch of depth. The more depth you install, the higher your total R-value. For Ontario attics, the benchmark most homeowners aim for is R-60. That is the level a properly upgraded attic should hit, no matter which method you use to get there.
Why R-60 specifically? Ontario winters are long, heating is expensive, and heat rises. An underinsulated attic is one of the biggest reasons a furnace runs overtime. In summer, the same problem works in reverse: heat builds up in the attic and radiates down into upstairs bedrooms, making the air conditioner work harder. R-60 is the point at which an Ontario attic is genuinely doing its job year-round.
Why 100% Coverage Matters More Than Method
The weakest spot in your attic determines how the whole thing performs.
Think about a winter jacket with a hole in the sleeve. It does not matter how warm the jacket is rated; you are going to feel that hole. Attic insulation works the same way. If 95% of your attic is insulated to R-60 and 5% is uncovered, compressed, or has gaps, the whole attic performs much closer to the weak 5% than the strong 95%. Heat always finds the path of least resistance, and gaps become that path.
This is why the method you choose matters so much. Whichever approach you pick has to give you even, continuous coverage across the entire attic floor – around pipes, wiring, light fixtures, and every bit of framing. A beautifully installed attic with a few missed corners performs noticeably worse than its R-value label suggests, and most homeowners never realize it because the problem is hidden above the ceiling.
That is where blown-in and batt start to look very different.
Blow-In vs. Batt: Quick Comparison
|
Factor |
Blown-In (ProPink L77) |
Batt |
|
How it is installed |
Machine-blown loose fill |
Hand-placed pre-cut panels |
|
Depth for R-60 |
About 22 inches |
About 16–20 inches (stacked layers) |
|
Coverage consistency |
Very high, fills every gap |
Depends on the installer’s precision |
|
Risk of gaps |
Low |
Moderate |
|
Works with existing insulation |
Yes, tops up easily |
Harder usually needs clean framing |
|
Best for |
Older homes, uneven framing, top-ups |
New builds, simple layouts |
For most Ontario attics, especially older homes, blown-in is the more reliable way to reach full R-60 coverage. For clean, well-built new homes, professionally installed batts can do the same job.
What Happens During a Blown-In Installation?
A professional blown-in installation is usually a one-day job for a typical Ontario home.
The crew arrives with a blowing machine that stays outside or in the driveway. A long hose runs from the machine up into your attic through the access hatch. One person feeds bags of insulation into the machine while another works in the attic, directing the hose to build up an even depth across the entire floor. If you are having your roof re-shingled at the same time, a sheet of plywood can be temporarily removed, and the insulation top-up can be done without entering your home.
Before any material is blown, a good crew will check your soffit vents and may install baffles at the eaves. These are simple cardboard or foam channels that keep the new insulation from drifting into the soffit openings and blocking airflow. Skip this step, and you solve one problem by creating another: a properly insulated attic with no way to breathe, which leads to moisture problems in winter.
After the blow is complete, the installer measures depth in several spots to confirm R-60 has been reached everywhere, not just in the middle. That final check is what separates a job that meets spec from one that simply looks finished.
What Should I Ask Before Hiring an Insulation Contractor?
A few simple questions will quickly tell you whether a contractor knows their work:
- Will you look at my attic before recommending a method?
- Can you explain why you are recommending blown-in or batt for my home?
- How will you check that the whole attic is covered evenly after the job is done?
- Will you install baffles at the soffits to protect airflow?
A contractor who cannot answer these clearly is guessing. Guessing is how you end up with an attic that looks insulated but performs nowhere near its rated R-value.
How JN Roofing Approaches Attic Insulation
When our team assesses your attic, we look at the whole picture: framing, clearance, existing insulation, ventilation, and anything in the way. If blown-in is the right call, we explain why, confirm the depth needed for R-60, install baffles where needed to protect airflow, and apply ProPink L77 to full coverage across the entire attic floor.
If your attic would genuinely be better served by batts, we tell you honestly and suggest you find a contractor whose specialty fits the job. We’d rather earn your trust than sell you the wrong service
One of the first things we look at is how your attic’s insulation and ventilation work together. Adding insulation can improve comfort and energy efficiency, but if the attic doesn’t have proper airflow, moisture can build up and cause bigger problems over time. By checking both during the same visit, we can make sure your attic is properly balanced and performing the way it should.
Not Sure Which Method Your Attic Needs?
The only way to know for sure is to have someone actually look. JN Roofing offers free, no-obligation attic assessments. We walk you through what we find, recommend the method most likely to get your attic to full R-60 coverage, and explain the work clearly before you commit to anything. If your attic is genuinely better suited to batt installation, we will tell you that – even though it is not what we do.
Book a Free Estimate: jnroofing.ca/get-an-estimate/
Frequently Asked Questions
What is the difference between blown-in and batt attic insulation?
Blown-in is a loose material that a machine blows across your attic floor, filling around every obstruction in one continuous layer. Batt is pre-cut panels laid between the joists by hand, usually in two stacked layers. Both can reach R-60 when installed well. Blown-in is more forgiving in uneven attics; batts can be better suited to clean, simple layouts.
Which is better for older Ontario homes?
Blown-in, in most cases. Older attics usually have irregular framing, pipes, wiring, and patchy existing insulation that make batts difficult to install without gaps. Blown-in material flows around all of that and gives more consistent coverage without needing to tear out what is already there.
How deep does attic insulation need to be to reach R-60?
With Owens Corning ProPink L77 blown-in, roughly 22 inches of settled material reaches R-60. With batts, you typically need 16 to 20 inches of stacked layers, depending on the product. Your contractor should confirm the exact depth for the specific material they are installing, and measure it in multiple spots after the job to make sure coverage is even.
Does attic insulation help in summer, too?
Yes. Insulation slows the heat moving in both directions. In winter, it keeps heat inside; in summer, it slows the heat from a hot attic from radiating down into upstairs bedrooms. Pairing proper insulation with working attic ventilation is the most effective combination for year-round comfort.
How long does a blown-in installation take?
For most Ontario homes, a blown-in attic insulation job takes a single day. Bigger homes, complex attics, or jobs that need significant prep work, like baffle installation or removal of old, damaged insulation, can stretch to a day and a half. Your contractor should be able to give you a reliable time estimate after assessing the attic.