Call Now 1.800.265.1914

Why Attic Insulation and Ventilation are So Important

November 23, 2015

Most builders and contractors believe that attics should be vented. The better contractors go one step further, and maintain that attic insulation and attic ventilation must go together. There are a myriad of opinions (not everyone agrees) but it's generally established that attic ventilation will benefit the home. A well-ventilated attic space will reduce moisture build-up and condensation, both of which are undesirable in the attic cavity. It will serve to lengthen the lifespan of roofing shingles. Air conditioning bills (cooling) will be reduced in the summer. And in winter, there is less chance of "ice dams" developing. Needless to say, attic ventilation is only one component. attic-insulation For homeowners planning to install attic insulation, most building codes will require venting and ventilation. Indeed, it may sound weird to install attic insulation to insulate the home, and then deliberately create air ventilation - but it's the combination of attic insulation and ventilation that assures energy-efficiency throughout home. In winter, natural airflow allows the attic to stay cold and therefore reduces the chances for unwanted "ice damming". In summer, natural airflow lets heated air be released from the attic (also removes moisture). As for the attic insulation itself, it will perform as required, resisting seasonal heat transfer in and out of the house. A common homeowner mistake with attic insulation is blocking off airflow. Better contractors don't make this mistake, especially when advocating for an installation that combines both attic insulation and attic ventilation in one. Hence, a do-it-yourself (DIY) approach to attic insulation is discouraged - mainly because undoing mistakes may be more costly than doing it right the first time. And while laying down fiberglass batts or blowing in cellulose sounds easy as a DIY project, there are other factors required to ensure an insulation "system" that delivers optimum results. With attic insulation, the best results, both short term and long, are derived with an expert install.

Attic Fans for Ventilation

An attic fan is designed to cool a hot attic by bringing cool air inside while flushing hot air out. If attic ventilation is blocked or if the attic insulation is not sufficiently sealing the space, the whole "system" will be not function - and utility bills will be unusually high from season to season.

Attic Insulation Strategies

No homeowner wants warm air (or cool air) to escape from the home. This is why attic insulation must provide appropriate air-sealing properties, and why attic ventilation must complete the "system". And here, a professional installation will ensure maximum performance in the attic.

Insulation Product Knowledge

Insulation experts have the product knowledge and installation experience to ensure that an attic insulation "system" is complete. From joists to framing; from light fixtures to soffit vents; and from loose fill insulation to fiberglass, it's the professionals who are experienced and proficient. The whole idea behind attic insulation is to deliver energy efficiency to the home. It should mean measurable savings on heating and cooling costs, as well as home comfort from season to season. And the bottom line for any homeowner: do it right the first time around.

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.

Please, enter a valid value

Incorrect values!