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Stay Cool This Summer By Insulating And Air Sealing Your Home

May 30, 2017

One of the most negative dynamics in a residential home is air leakage - it has more negative effect on home energy efficiency than anything else. From a professional perspective, a home must be sealed air tight in order to achieve optimum energy efficiencies. And for the home energy experts at Great Northern Insulation, addressing air leakage by air sealing is the first step before anything else. Effective air sealing is essential for proper air ventilation and air circulation throughout a home. Since every home operates as a "system", air sealing and ventilation ensures that everything is working in better balance. One thing for sure, the HVAC system (heating and cooling) will work more efficiently, and will consequently improve energy efficiency in winter and summer.

Assessing and testing for air leakage throughout the building envelope

In assessing air leakage, Great Northern Insulation uses a Blower Door Test to accurately calculate air leakage in a home. The idea with this test is to depressurize the "building envelope", and allow for an assessment of airtightness. GNI measures the amount of air leakage throughout various parts of a home in "air changes per hour" - usually at a pressure 50 Pascals (ACH50). By using special equipment, a Blower Door Test clearly identifies air infiltration from windows, doors, and any other cracks or openings. Once the air leakage has been assessed, a home's energy efficiency can be rated accurately. What's more important is that GNI can propose retrofit and upgrade measures to effectively eliminate the air leakage (and improve energy efficiency).

The Blower Door Test and subsequent assessment can lead to action

In professional circles, the Blower Door Test is one of the more valuable tools when undertaking a residential energy audit. Airflow coming in and going out of the home is measured in CFMs (cubic feet per minute). Depending on the amount of air leakage, there are a host of upgrades and improvements that can be engineered in order to enhance energy efficiency and performance. The goal of any upgrades or improvements is to seal the "building envelope", thus preventing any undesirable air infiltration. This is where GNI can provide remedies - from air sealing to weatherization, to insulation. When completed, some or all of the remedies will serve to improve the home's energy efficiency, and reduce seasonal utility bills for heating and cooling the home.

Home energy efficiency is about BOTH insulating AND air sealing

In the majority of residential homes, property owners focus on home insulation when addressing energy efficiency. While this approach will yield results, it's only one part of the picture. In fact, air leakage in a home has proven to be much more impactful in compromising energy efficiency. For the professionals at Great Northern Insulation, a home needs to be sealed tight in order to effectively manage airflow that is moving in and out of the "building envelope". As a complete system, air sealing, thermal insulation, and air ventilation all contribute to energy efficiency.

Spray Foam Insulation (SFI) is the ultimate sealer and insulator

As experts with Spray Foam Insulation, GNI highly recommends these products for application in the attic, basement, and even exterior walls. SFI outlasts and outperforms other comparable products - it's an application that seals and insulates at one time, and never needs replacement. Spray Foam Insulation seals a space airtight, and can fill even the most awkward corners and edges in the roof and basement. Professionally applied, SFI creates an air barrier and vapour barrier at the same time, and therefore prevents unwanted air moisture from accumulating. In summer, it's easy to stay cool when the home is properly insulated and air sealed with Spray Foam Insulation. When compared with other products, SFI will deliver better energy efficiency in the short term, and far better performance in the long term. And that means utility savings.

Great Northern Insulation assesses a home's energy efficiency

While windows and doors do contribute to air leakage, there are numerous other sources throughout the "building envelope" of a home. In total, air leaks throughout a home can create as much leakage as a wide-open window. This is a recipe for wasting energy in winter and summer. GNI isolates and identifies air leakage from the top of the "building envelope" to the bottom. This allows for the most accurate assessment of areas that require improvement. By sealing walls, floors, and attic cavities, air movement is curtailed and energy efficiency is measurable enhanced. A home that is well sealed, well insulated, and well ventilated is a home that will perform well. The entire indoor environment is benefited - there are fewer drafts, much less noise, and better indoor air quality. Best of all, with improved energy efficiency, seasonal utility bills are lessened.

Cool in summer, warm in winter, makes a comfortable home

For energy efficiency and home comfort, spray foam insulation delivers more benefits than anything comparable. Professionally installed, spray foam will provide air tightness and high R-Values at one time. It will prevent air from leaking out of the home, and prevent air from entering the home. Finally, it will improve energy efficiencies while reducing energy consumption. With improved home energy efficiency, homeowners can dramatically reduce energy usage in winter and summer, and can therefore reduce utility bills for heating and cooling. As well, the home will remain cool in summer and warm in winter, without having to adjust and re-adjust the thermostat. Gone are the days of uncomfortable drafts, cold rooms, and undesirable humidity. Great Northern Insulation has experienced installers who specialize with spray foam. Everything is installed to code. Every application follows manufacturer specifications. And every installation is guaranteed by GNI. In short, Great Northern Insulation provides the retrofit options that best suit the job - and the best return-on-investment, based on the homeowner's project budget. For an on-site home energy assessment, call 1-888-778-9591 or check the company website at www.gni.ca .

Western Ontario

935 Keyes Drive
Woodstock, Ontario
Canada N4V 1C3

Phone: 1-800-265-1914

Fax: (519) 539-7946
TOLL FREE: 1-800-265-1914

Muskoka, Haliburton, Northern Ontario

1027 Elwell Park Road
Gravenhurst, Ontario
Canada P1P 1R1

TOLL FREE: 1-800-265-1914

Central Ontario

29 Ferndale Industrial Drive
Barrie, Ontario
Canada L4N 9V5

TOLL FREE: 1-800-265-1914

Greater Toronto Area

2 Guided Court
Etobicoke, ON
M9V 4K6

TOLL FREE: 1-800-265-1914

GTA East

103 North Port Road
Port Perry, Ontario
Canada L9L 1B2

TOLL FREE: 1-800-265-1914

South Central Ontario

450 Industrial Dr,
Toronto (Milton), Ontario
Canada L9T 5A6

TOLL FREE: 1-800-265-1914

Eastern Ontario

1035 Moodie Dr #1,
Nepean, ON
K2R 1H4

TOLL FREE: 1-800-265-1914

Niagara Region

25 Lincoln Ave
St. Catharines, ON
L2P 2C7

TOLL FREE: 1-800-265-1914


Great Northern Insulation - Better Business Bureau Profile.

Homestars Best of 2021 Award

Best of 2021

HomeStars has ranked Great Northern Insulation as a company that goes above and beyond in every aspect of business for the year of 2021.

Homestars Best of 2022 Award

Best of 2022

HomeStars has ranked Great Northern Insulation as a company that goes above and beyond in every aspect of business for the year of 2022.


GNI is the Authorized & Trusted Insulation and Air Sealing Installer for Lowe’s

Trusted for Over 40 Years

Over 40 Years in Business

At GNI, we service your project with the most experienced staff in the industry. Ongoing professional development is an obsession at GNI and we will not compromise at any level to bring to our customers the very best Installers, Sales Representatives, Customer Care Personnel, Field Superintendents, Estimating and Technical Support to your project.

100% Canadian

100% Canadian

Great Northern Insulation is recognized as Canada's largest full-service insulation contractor. GNI is 100% Canadian owned, proudly serving Ontario customers since 1980.

Foam Masters

Do it right the first time
- with foam mastersTM

January, 2021 regulatory phaseout of hydrofluorocarbons (HFCs) with the introduction of WALLTITE CM01. Using hydrofluorolefins (HFOs) with lower global warming potential (GWP) compared to HFCs, WALLTITE CM01 is the next generation of spray foam insulation.



Heatlok® Soya HFOTM leverages Honeywell’s latest Solstice® Liquid Blowing Agent technology. This new hydrofluoroolefin (HFO) blowing agent is the most environmentally conscious blowing agent produced to date, with a zero ozone depletion potential (ODP) and a global warming potential (GWP) of 1, which is more than two orders of magnitude (99.9%) lower than HFCs used in this industry.


3MTM products.
Quality + Performance = Savings

3MTM energy-saving products are designed to keep warm air in, and cold air out, while keeping energy bills down. Products optimize energy efficiency in buildings and homes; improve indoor environment for occupants; and effect the reduction of seasonal energy costs. 3M products are authorized for LEED credits (Leadership in Energy/Environmental Design).

Holmes and Holmes

Holmes and Holmes


Mike Holmes and his son Mike Jr. (MJ) convert MJ’s bachelor bungalow into a two-storey home for MJ and his girlfriend Lisa. Choosing the newest materials and build techniques, the father and son team follow Mike’s famous motto – “Make it right.” The show can be watched on HGTV and DIY Network.


Enbridge Incentives

The Home Efficiency Rebate Plus program offers up to $10,000 in home reno rebates – and Great Northern Insulation can pave the way.


Great Northern Insulation proudly abides by a renovation-specific Code of Conduct set by RenoMark™.


We are Verified & Bonded by eRenovate. When you choose to proceed with our services through their platform, you receive the gaurantees set forth through their program.

As Seen on Love It or List It

The GNI crew have been featured installing insulation on Love It or List It - have you seen our logo in an episode?

Climatizer Cellulose


CLIMATIZER PLUS cellulose insulation is manufactured from a minimum of 85% locally-sourced post-consumer recycled newsprint. Non-toxic additives are applied to the uniquely fiberized paper generating a building material with superior thermal and acoustic properties, as well as exceptional resistance to fire, moisture, mould and pests.

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