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The Importance of Home Ventilation

Horizon Cantilever 1100 open gas fireplace

As Australia transitions to 7-star energy-efficient homes under the National Construction Code (NCC), it’s important to consider the role of ventilation in maintaining healthy living environments. Although various ventilation standards exist across different regions and sectors, they all emphasise one critical point: proper air changes per hour (ACH) are essential for healthy indoor air quality.

  • National Building Code of Australia (Part 3.8.5): Requires 10% of the floor space to be ventilated by windows and other openings.
  • Victorian Health: Recommends 4-5 air changes per hour (ACH).
  • ASHRAE (American Society of Heating, Refrigeration and Air Conditioning Engineers): Recommends a minimum of 0.35% of air within a space to be replaced per hour.
  • AIHA (American Industrial Hygiene Association): Requires up to 20 complete air changes per hour in certain settings.

Despite these differences, all these standards agree on one thing: adequate air exchange is key to ensuring indoor air quality and the well-being of occupants. However, the NCC’s requirements for 7-star energy-efficient homes, with their focus on airtightness and minimal energy loss, often result in insufficient air changes unless addressed through strategic ventilation design. Without proper mechanical or natural ventilation, these homes risk becoming unhealthy due to poor air circulation, leading to moisture buildup, mould, and other indoor air quality issues.

The Importance of Ventilation in 7-Star Homes:

In more tightly sealed, energy-efficient homes, adequate ventilation is crucial. It helps to prevent the buildup of harmful pollutants, allergens, and moisture, which can negatively impact the living environment. Importantly, proper ventilation helps to:

  • Retain the efficiency of the heating and cooling systems installed within the home
  • Dilute and disperse airborne particles such as dust, pollen, and microorganisms, improving air quality.
  • Reduce the risk of mould formation due to moisture accumulation, a common issue in poorly ventilated or incorrectly vented spaces.
  • Decrease the transmission of infectious respiratory particles by ensuring regular air exchange.

Minimum Air Changes Per Hour (ACH) – Meeting the Standard:

A key requirement for healthy indoor environments is achieving 4-5 air changes per hour (ACH) at a minimum. This means the entire volume of air in a home should be replaced 4 to 5 times per hour to effectively manage air quality. But with modern construction focusing on airtightness to meet 7-star energy ratings, how can we achieve this if fresh air is not being introduced mechanically or naturally?

Without proper airflow, homes may trap moisture and contaminants, leading to negative outcomes such as mould growth, condensation, and poor air quality—factors that can undermine the health of the occupants and the structure of the home.

The Role of Stack Ventilation:

One solution is the strategic use of  ‘stack ventilation’, a natural method that utilises the difference in air pressure between lower and higher points in the home. By placing vents in the correct locations—ideally at low and high points—this method encourages a natural flow of air, drawing fresh air in and expelling stale air. When designed and implemented correctly, stack ventilation can significantly improve air exchange without compromising the energy efficiency of a 7-star home.

Using Open Gas-Flued Fireplaces or natural draft wood burning fireplaces in Ventilated Homes:

Installing a natural drawing appliance such as a wood burning or gas burning natural draft appliance with adequate air flow within the room the appliance is situated will provide a natural stack ventilation principle to occur as the flue will exit the top of building and air will enter low down within the room the appliance is situated. This supplies a natural efficient balanced stack air flow within home while allowing the heat from the appliance to rise within the home creating warmth and efficiency.(show drawing of our outside air kit).

The Risk of Poor Ventilation:

Good ventilation adds to the overall efficiency of home. Bad ventilation (i.e. the incorrect location of vent locations within home can cause poor efficiency). When a home is sealed and principles of stack ventilation are not understood then natural ventilation openings such as windows, permanent ventilation for bathrooms, kitchens, laundries etc. can cause negative pressures leading to homes becoming not only unhealthy but less efficient. If the home only ventilates from the top and does not have equal air entering the bottom of the home, then cold air will be drawn into the home filling the home with cold air. Understanding stack ventilation will allow builders and architects to design vent openings within the home to allow adequate air changes without negative health and efficiency compromise.

Ensuring Healthy, Energy-Efficient Homes:

By addressing the need for 4-5 ACH through mechanical or natural methods and using smart ventilation strategies, it is possible to balance the goals of energy efficiency with the health and comfort of occupants in 7-star rated homes. Properly vented homes allow for the use of open gas-flued or natural draft wood  fireplaces while maintaining air quality and preventing moisture-related problems.

We encourage the NCC to consider these factors when guiding energy-efficient home construction, ensuring that ventilation remains a top priority for safe, comfortable, and sustainable living environments.

For more information on how Jetmaster Fireplaces can be integrated into well-ventilated, energy-efficient homes, please feel free to contact us.

Stacked ventilation

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