At the heart of the solution is the building envelope—when it’s airtight and properly ventilated, everything else performs better. By sealing invisible leaks and addressing the building envelope, the Energytight™ solution creates a solid foundation for energy savings, health, and comfort.
Combined with balanced mechanical ventilation, Energytight™ homes:
Backed by certified results—proven airtightness, not just promises
Addressing air leakage not only boosts energy performance but also improves health, comfort, and building durability:
Proven results:
BRANZ empirical research shows that improving airtightness from 9 to 1 ACH50 reduced energy use by 50%, and when combined with heat recovery ventilation, the total reduction reached 90%
Airtightness is measured with a blower door test. A fan is temporarily fitted into an exterior door to gently pressurise or depressurise the home. This shows how much air is leaking through gaps and cracks in the building.
Mechanical ventilation and airtightness are designed to work as a system—one simply doesn’t perform well without the other. In a leaky home, air escapes through gaps—bypassing the ventilation system and wasting heating and cooling energy. In an airtight home, most air flows through the system, allowing it to filter air properly and recover heat efficiently. This means better air quality, lower energy use, and smaller, more effective systems.
Airtightness makes the whole home, work better.
Many homes in New Zealand—even architecturally designed ones—still leak significant amounts of air, reducing energy efficiency and comfort. The Energytight™ solution lowers air leakage to below 3 ACH50, dramatically improving energy performance, comfort, and indoor air quality—across all price ranges.
Thanks to AeroBarrier, this level of airtightness can be achieved without changing standard construction methods—making Energytight™ one of the most cost-effective ways to build a high-performance home.
As the chart shows, Energytight™ homes sit comfortably within the low cost range for new builds—delivering better performance without the price premium.
A house needs to breathe—but it should do so in a controlled, consistent way, not just when the windows are open. In an airtight home with proper ventilation, fresh air can flow continuously without relying on open windows or losing valuable heat. This manages internal moisture, reducing condensation, musty smells, and the risk of hidden mould—creating a home that feels fresher, more stable in temperature, and noticeably more comfortable every day.
A house needs to breathe—but it should do so in a controlled, consistent way, not just when the windows are open. In an airtight home with proper ventilation, fresh air can flow continuously without relying on open windows or losing valuable heat. This manages internal moisture, reducing condensation, musty smells, and the risk of hidden mould—creating a home that feels fresher, more stable in temperature, and noticeably more comfortable every day.
Energy efficiency is no longer just about comfort—it’s a key driver in property value and saleability.
Homes with certified energy ratings consistently outperform the market
Buyers Are Focused on Energy Costs
Certification Matters
An EnergytightTM certificate proves performance—it’s not enough to just say a home is energy efficient
Energytight™ Certification
Verified by blower door testing, Energytight™ offers two levels:
Retrofit Certified: For existing homes. Aims to reduce air leakage to 10 ACH50 or better—improving energy efficiency, comfort, and air quality to levels comparable to, or better than, a typical new home.
New Home Certified: For new builds. Achieves 3 ACH50 or better—meeting international best practice for energy efficiency, comfort, and durability.
Note: Every home is different, and while Energytight™ aims to deliver excellent results in both new builds and retrofits, outcomes depend on many factors—read our full disclaimer here to learn more.
Addressing airtightness is a low-cost, low-disruption way to significantly improve a home’s comfort, health, and energy efficiency. The staged approach outlined below is based on performance data from the IECC 2012.
Instead of tackling the costly and disruptive process of retrofitting wall insulation, addressing airtightness and ventilation first delivers greater overall performance at a fraction of the cost. Wall insulation can still be added in a future stage. But with AeroBarrier airsealing and mechanical ventilation, Stage 1 already achieves more energy savings than traditional methods—without the disruption.
Traditional Renovation
(Wall insulation, not airtightness)
Potential Energy Use Reduction 61%
Energytight™ Retrofit
(Airtightness and windows, not insulation)
Potential Energy Use Reduction 67%
Deep Renovation
(Traditional renovation plus Airtightness)
Potential Energy Use Reduction 100%
Source: Based on IECC data from NEHERS presentation, ANSI/RESNET Conference, November 2023 and ENERGY STAR publications.
This case highlights how energy-efficient, healthy, and durable homes can be delivered affordable when airtightness and ventilation are prioritised.
Summary
Starting airtightness: 19 ACH50
Final airtightness: 1.7 ACH50
Achieved Homestar 7
Key goal: Prove that ambitious airtightness targets (below 3.0 ACH50) can be achieved in typical homes
“We’ve taken a 1970s Kāinga Ora home from 19 air changes down to just 1.7 ACH50—a level of performance well beyond most new builds. Absolutely amazing.”
Ready to upgrade your home’s performance? Contact Aero for a consultation and learn how the Energytight™ solution can transform your space.
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