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Aero Study Report

Enbridge Review: Impact on Energy Use

Background

This study quantifies measured energy savings from residential airtightness improvements using large Canadian utility datasets. Airtightness reductions of 40–70 percent lowered ACH50 from typical pre levels of 4–8 to post levels of 1–3. These changes delivered consistent heating energy savings of 15–30 percent, equivalent to 8–25 GJ per home per year. Energy savings scaled closely with ACH50 reduction, with the largest gains in homes starting above 5 ACH. Results align with building physics theory and show strong relevance for New Zealand housing, where baseline leakage rates are high.

Highlights

Airtightness gains delivered 15-30 percent heating energy reductions across measured homes.
Leakage cuts of 40-70 percent shifted homes from 4-8 to 1-3 ACH50.
Each 1.0 ACH50 reduction saved 4-10 GJ or 5-15 percent heating.
Savings were strongest in leaky homes above 5 ACH, matching New Zealand conditions.

Measured Energy Savings from Airtightness Improvements

The dataset shows that improving airtightness with AeroBarrier produced typical energy savings of:

≈ 15–30% reduction in total heating energy
or
≈ 8–25 GJ per home per year saved**

Utility case study results

Absolute savings: GJ Savings: values commonly in the range of 8–25 GJ per year
Relative savings: % GJ Savings vs Base Case: most commonly 15%–30%

What level of airtightness improvement produced these savings?

The results show:

AB Pre ACH (before AeroBarrier)
AB Post ACH (right after AeroBarrier)
Measured Post ACH (final blower door at closing)

Typical improvements:

Pre ACH50: 4–8 ACH
Post ACH50: 1–3 ACH
Reduction: often 40–70% reduction in leakage

This improvement in airtightness explains the corresponding energy savings.

The relationship between airtightness improvement and energy savings

Looking across projects:

For each 1.0 ACH50 reduction, homes generally saved:

≈ 4–10 GJ/year
≈ 150–350 m³ gas/year
≈ 5–15% heating energy

This aligns with building-physics modelling and other North American datasets.

In other words:

Tightening a home from ~5 ACH → ~2 ACH can reduce heating demand by 20–30%.

Why airtightness improves energy efficiency

Airtightness affects:

Infiltration load (sensible heating)
Moisture load (latent heating)
Ventilation system performance (capture efficiency)
Drafts and cold air wash inside the envelope

Reducing infiltration through AeroBarrier:

Reduces uncontrolled air changes
Ensures heated air stays inside longer
Allows mechanical ventilation to operate more efficiently
Reduces moisture load from cold, dry external air
Increases comfort, which sometimes reduces thermostat setpoints

These effects explain the observed energy savings.

Does the dataset show diminishing returns?

Yes.

For homes that were already near 3.0 ACH:

Reducing to 1.5–2.0 ACH produced modest energy savings (5–10%)

But for homes:

Starting above 5–6 ACH,
Reducing to below 3 ACH,

→ Savings are dramatic (20–40% total heating energy).

This is exactly the range NZ homes tend to operate in (5–15 ACH typical), meaning AeroBarrier has even greater relative value in New Zealand.

NZ Equivalent Energy Savings (converted)

Using NZ climate and heat pump COP assumptions:

Every 1.0 ACH50 reduction saves ≈ 150–350 kWh/year in NZ climates

so: A reduction from 8 ACH → 3 ACH would save: ≈ 750–1,750 kWh/year, depending on climate zone.

Airtightness Performance and Energy Savings Results

Across all homes:

AeroBarrier reduced airtightness by 40–70%, producing:

Energy savings of:

8–25 GJ/year
15–30% heating load reduction
100–600 kWh saved

This is exceptionally strong performance for a single-day intervention.

Some images on this page have been AI-generated by Gemini