What is the Best R-Value for Insulation in Ontario Homes?

In simple terms, R-value measures how well an insulation material resists heat transfer. The higher the R-value, the better the material insulates. For example, an insulation rated R-20 performs better than one rated R-10 because it slows down heat flow more effectively.

Different materials have different R-values per inch of thickness:

Ontario’s climate experiences cold winters, humid summers, and frequent temperature swings — meaning insulation must handle both heat retention and moisture control. The Ontario Building Code (OBC) sets minimum R-value standards for different parts of your home, but many energy-efficient homeowners choose to exceed those numbers for better comfort and long-term savings.

Here are the general R-value recommendations for Ontario homes:

Yes, absolutely — insulation requirements do vary across Ontario based on climate zones and heating-degree days (HDD). Below is a reference table of recommended R-values for different parts of a home in Ontario, grouped by general region (Southern vs Northern Ontario). These are guideline targets based on current building code minimums and industry best practices — actual requirements may differ based on your exact municipality, building type, retrofit vs new build, and whether you’re pursuing energy-efficiency upgrades.

Choosing the right R-value depends on your home’s age, structure, and exposure to weather. Older homes often have minimal insulation or air gaps that can dramatically reduce efficiency. In those cases, upgrading to closed-cell spray foam offers the most effective and permanent solution.

For newer homes or renovations, our team can tailor the insulation type and R-value for each part of the house — attic, basement, walls, or garage — ensuring you meet or exceed Ontario’s energy standards.



We don’t just focus on hitting a number — we focus on creating a complete insulation system that delivers real-world performance and long-term savings.

While R-value tells you how much resistance insulation provides, it doesn’t measure how well your home is sealed. Even high R-value insulation can underperform if there are air leaks, gaps, or moisture issues.

For example, traditional materials like fibreglass batts or blown-in cellulose often leave small gaps around outlets, light fixtures, or framing, allowing warm air to escape and cold drafts to enter. That’s why spray foam insulation — which expands to fill every crack and cavity — delivers superior real-world performance.

Spray foam not only provides a higher R-value per inch but also acts as an air and vapour barrier, sealing leaks that traditional insulation can’t reach. The result? A home that stays warmer in winter, cooler in summer, and more energy-efficient year-round.

At Newmarket Spray Foam Insulation, we specialize in both open-cell and closed-cell spray foam systems. Here’s why spray foam is the preferred solution for so many homeowners across York Region and beyond:

1. Superior R-Value and Air Sealing

Closed-cell spray foam provides up to R-7 per inch, one of the highest ratings available. It also seals air leaks and moisture entry points, which significantly improves energy efficiency beyond what R-value alone can achieve.

2. Moisture and Mould Protection

Basements, attics, and crawl spaces in Ontario are especially prone to condensation. Spray foam insulation prevents moisture buildup by creating an airtight barrier, helping protect your home’s structure and indoor air quality.

3. Lower Energy Bills

A properly insulated and sealed home can reduce heating and cooling costs by up to 40%. That’s not just good for your wallet — it’s great for the environment, too.

4. Durability and Longevity

Unlike fibreglass or cellulose, spray foam doesn’t sag, settle, or degrade over time. Once applied, it maintains its performance for decades without the need for maintenance or replacement.

5. Improved Indoor Comfort

Spray foam eliminates cold drafts, uneven temperatures, and hot or cold spots — giving you consistent comfort throughout every room of your home.

Upgrading your insulation doesn’t just save energy — it also increases your property’s value and appeal. Potential buyers today are more eco-conscious and energy-aware than ever before. A home with professional spray foam insulation offers:

• Higher resale value due to reduced energy costs
• Increased durability with fewer moisture and mould concerns
• Improved indoor air quality for healthier living
• Enhanced comfort with stable indoor temperatures year-round

At Newmarket Spray Foam Insulation, we’ve helped hundreds of homeowners across Ontario transform their homes into energy-efficient, comfortable spaces that perform better in every season.