Can air sealing alone reduce my heating bill in New Brunswick? | Insulation IQ?

Yes — and the savings can be surprisingly significant. Air sealing is often overlooked because it's invisible once complete, but in a leaky New Brunswick home, it can reduce heating costs by 15% to 40% depending on how drafty the building is to begin with. In some older homes in Fredericton, Moncton, or Saint John built before the 1980s — when air tightness simply wasn't part of the building culture — air sealing alone can be one of the highest-return investments available.

To understand why, consider how heat actually escapes your home. Most people picture heat flowing outward through walls and ceilings (thermal conduction through insulation), and that's real. But uncontrolled air leakage — infiltration — is responsible for 25% to 40% of the total heating load in a typical older Canadian home. This is warm, conditioned air physically escaping through cracks around electrical boxes, plumbing penetrations, attic hatches, around rim joists at the foundation, and at partition wall top plates. Cold air simultaneously enters through similar gaps at lower levels, creating a continuous convective loop called the stack effect that intensifies in Zone 6 winters.

New Brunswick's winters are harsh enough that this matters enormously. Fredericton sees average lows of around -13 degrees Celsius in January; Moncton and Saint John aren't far behind. When outdoor temperatures are that far below indoor setpoints, every cubic foot of warm air that escapes is replaced by extremely cold air your heating system must condition. The annual heating cost penalty from a leaky building envelope can run $400–$900 or more for a typical 1,500-square-foot home, depending on fuel type. With heating oil prices hovering around $1.50–$1.80 per litre in New Brunswick in recent years, that adds up fast.

The most impactful air sealing targets in a typical NB home are:

The attic floor is usually the single biggest opportunity. Warm air rises and exits through the top of the building envelope — around pot lights, at the attic hatch, where interior walls meet the top plate, and through any plumbing or electrical penetrations through the ceiling. Sealing the attic floor with spray foam and acoustical sealant before adding blown insulation can dramatically cut infiltration.

The rim joist at the foundation-to-floor junction is another major leakage zone, often completely uninsulated and unaired in older homes. Two inches of closed-cell spray foam here ($300–$600 for a typical home) both insulates and air seals simultaneously.

Electrical boxes on exterior walls and ceilings, plumbing penetrations, and the gaps around bathroom exhaust fans all contribute to leakage that adds up across an entire house.

A blower door test, offered by certified energy advisors across New Brunswick, quantifies exactly how leaky your home is and identifies the specific locations of major leakage zones. This test is required as part of the Canada Greener Homes Grant application (worth up to $5,600 for eligible energy efficiency upgrades) and the NB Power Home Energy Efficiency Rebates program. Getting a pre-retrofit EnerGuide assessment done first means you can claim rebates on both air sealing and insulation work — often $500–$1,500 back for comprehensive air sealing improvements.

The practical answer to your question is nuanced: air sealing alone can reduce your bill meaningfully, especially in a pre-1980s home in Moncton or Fredericton, but the biggest wins come when air sealing and insulation upgrades are done together. Insulation without air sealing lets convective looping within cavities undermine the R-value. Air sealing without adequate insulation reduces infiltration losses but doesn't address conductive losses. Done together — particularly attic air sealing followed by blown-in insulation to R-50 or higher — the combination can cut heating bills by 30–50% in some older NB homes.

If you haven't had a professional energy audit done, that's the logical first step. It will tell you precisely where your home is losing the most heat, prioritise your investments, and unlock available rebates. The qualified insulation professionals listed through New Brunswick Insulation and the New Brunswick Construction Network can guide you through both the air sealing work and the rebate application process.

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Looking for experienced contractors? The New Brunswick Construction Network connects homeowners with qualified professionals:

• Arctic Fox Construction Inc.
• Thirty Four Renovations
• 3Tone Construction Ltd
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• Gionetterenovations