What Kind of Insulation Should I Use In My Home? A Complete Guide.
- Josh Mior
- Feb 12
- 5 min read
In our last blog we went over the requirements from the National Building Code of Canada for the minimum amounts you need to insulate on your next project. However this leads us right into another question What kind of insulation should I use in my home?
Choosing the right insulation is an important decision and the right choice heavily affects your home's comfort, energy efficiency, air quality and long-term performance. Along with how it performs the type, thickness and quantity all play a part in how the project gets designed. Safe to say designing your project starts from the inside out.
But with so many options available, how do you decide?
This guide breaks down the most common insulation types, their pros and cons, and where each performs best.
Batt Insulation:
Batt insulation comes in pre-cut sections (can be fiberglass, mineral wool or natural fibers) designed to fit between standard stud spacing.
Fiberglass Batts (Owens Corning)
Pros:
Widely available
Cost Effective
Easy for DIYers to install
Good for standard wall cavities
Cons:
Absorbs moisture
Combustable
Performance drops significantly if compressed or poorly installed
Difficult to fit around obstacles (pipes, wires, blocking)
Provides no continuous insulation over framing
Can leave gaps if not carefully installed
Best for: Budget-conscious projects with simple, open wall cavities
Mineral Wool Batts (Roxul/Rockwool)
Pros:
Excellent fire resistance
Superior sound dampening
Higher density than fiberglass—better performance
Doesn't wick moisture
Maintains R-value when compressed
Can be cut precisely to fit around obstacles
Cons:
More expensive than fiberglass
Heavier and slightly harder to handle
Best for: Fire-conscious builders, sound control applications, and higher-performance wall assemblies.
Rigid Insulation
Rigid foam boards provide continuous insulation, often used on the exterior of wall assemblies or under slabs.
EPS (Expanded Polystyrene)
Pros:
Most affordable rigid foam option
Vapor permeable—allows drying to the exterior
Recyclable
Cons:
Lower R-value per inch (~R-4) compared to other foams
Can absorb and hold moisture
Very combustable
Less durable—dents and breaks more easily
Requires thicker layers for high R-values
Best for: Budget-friendly continuous exterior insulation.
XPS (Extruded Polystyrene)
Pros:
Higher R-value per inch (~R-5) than EPS
Moisture resistant
Higher compressive strength—good under slabs
Durable and easy to work with
Cons:
More expensive than EPS
Vapor semi-permeable—can trap moisture in some assemblies
R-value can degrade over time due to off-gassing
Environmental and health concerns with blowing agents
Best for: Below-grade applications, under slabs.
GPS (Graphite Polystyrene)
Pros:
Higher R-value per inch (~R-5) than standard EPS
Vapor permeable like EPS
Better thermal performance in thinner profiles
Recyclable
Bug resistance from the infused graphite
Cons:
More expensive than standard EPS
Still less compressive strength than XPS
Best for: Exterior continuous insulation where higher R-value per inch is needed without sacrificing vapor permeability.
Rigid Mineral Wool (Roxul ComfortBoard)
Pros:
Excellent fire resistance
Vapor permeable—excellent drying potential
Great sound dampening
Won't melt or off-gas
Maintains performance when wet
Cons:
More expensive than foam boards
Heavier and bulkier
Best for: Fire-rated assemblies, passive house projects, and assemblies prioritizing vapor permeability and drying capacity.
Rigid Wood Fiber
Pros:
Carbon-negative material (stores carbon)
Vapor permeable with excellent moisture buffering
High thermal mass—stabilizes indoor temperatures
Renewable and sustainable
Great fire resistance
Cons:
As expensive as Ridged Mineral Wool
Limited availability in North America
Best for: High-performance green building projects, passive house construction, and builders prioritizing sustainability and hygrothermal performance.
Spray Foam
Spray foam expands on contact and provides insulation and possible air sealing in one step.
Closed-Cell Spray Foam
Pros:
Highest R-value per inch (~R-6 to R-7)
Provides structure—adds racking strength to walls
Excellent air sealing
Moisture barrier at sufficient thickness
Good for tight spaces and irregular cavities
Cons:
Most expensive insulation option
Vapor impermeable—can trap moisture if not designed properly
Difficult to remove or modify later
Installation requires professional equipment and expertise
Off-gassing concerns—requires proper curing time
Not repairable if damaged
Best for: Difficult-to-insulate areas, cathedral ceilings, rim joists, and applications where air sealing and high R-value are critical.
Open-Cell Spray Foam
Pros:
Excellent air sealing
Vapor permeable—allows drying
Expands significantly—fills all gaps
Better sound dampening than closed-cell
Less expensive than closed-cell
Cons:
Lower R-value per inch (~R-3.5)
Can absorb moisture
Requires more thickness for equivalent R-value
Still requires professional installation
Off-gassing concerns during application
Best for: Interior applications where air sealing is the priority and vapor permeability is desired, such as walls in mixed or humid climates.
Dense-Pack Cellulose
Cellulose insulation (made from recycled paper) blown densely into wall or attic cavities.
Pros:
Made from recycled content—environmentally friendly
Good fire resistance (treated with borate)
Fills irregular cavities completely
Pest and mold resistant (due to borate treatment)
Can be installed in existing walls through small holes
Good sound dampening
Lower cost than spray foam
Cons:
Requires professional installation with specialized equipment
Can settle over time if not installed at proper density
Slightly hygroscopic—absorbs and releases moisture
Adds weight to wall assemblies
Can be messy during installation
Best for: Retrofit projects, existing wall cavities, attics, and builders looking for high-performance insulation with lower environmental impact than foam.
ICF (Insulated Concrete Forms)
ICF systems use interlocking foam forms that remain in place as permanent insulation after concrete is poured inside. The result is a solid concrete wall sandwiched between rigid foam insulation.
Pros:
Exceptional thermal mass—stabilizes indoor temperatures
Superior structural strength and disaster resistance (hurricanes, tornadoes, earthquakes)
Built-in insulation and structure in one system
Excellent sound dampening
High R-values (typically R-22 to R-50 depending on system)
Air-tight construction when properly detailed
Pest and fire resistant
Fast framing process once forms are set
Long-term durability—extremely low maintenance
Cons:
Higher material costs
Requires specialized training and experience
Limited ability to modify walls after concrete is poured
Heavier foundation requirements due to concrete weight
Plumbing and electrical require careful planning before pour
Foam insulation may not align with green building preferences
Less forgiving of construction errors
Best for: High-performance homes prioritizing durability and resilience, disaster-prone regions and great soundproofing.
SIP Panels (Structural Insulated Panels)
SIPs are prefabricated panels consisting of rigid foam insulation sandwiched between two structural facings (typically oriented strand board). Panels arrive on site pre-cut and ready to assemble.
Pros:
Extremely fast installation—walls and roof can go up in days
Continuous insulation with minimal thermal bridging
Excellent airtightness when properly sealed
High R-values (typically R-14 to R-30+ depending on thickness)
Structural and insulation in one system
Precision manufacturing
Cons:
Higher upfront cost than stick framing
Requires crane or specialized equipment for installation
Lead time for manufacturing—less flexibility for design changes
Electrical and plumbing chases must be pre-planned or cut on site
Modifications after installation are difficult
Foam insulation may off-gas during cutting
Requires experienced installers familiar with SIP details
Panels can be damaged during shipping or handling
Best for: Fast-track construction schedules, remote building sites.
The Bottom Line
So, what kind of insulation should you use?
Ultimately, it's up to you, your builder, and your designer—but someone needs to choose. Each insulation type has its strengths and weaknesses, and the right choice depends on your specific situation.
But here's the truth: there's no single "best" insulation—only the best insulation for your specific project, climate, budget, and performance goals.
The key is understanding the trade-offs and designing your wall assembly as a complete system: insulation, air sealing, vapour management, and moisture control all working together.
When in doubt, consult with a builder or energy consultant who understands building science and can help you choose the right materials for your home's long-term performance.
Need Help?
Have questions about what type of insulation you should use on your next project or how to make it work? Call us at (506) 262-5913 or email info@ijmbuilders.com.
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