Subfloor Ventilation Guide

These are the very systems you’re looking at now — our exclusive Fresh Ventilation ducted subfloor ventilation systems, designed and refined through years of hands-on experience and comparison against competing products. Unlike basic wall fans or passive vents, our systems use inline centrifugal fans and ducting installed within the subfloor space, allowing precise and powerful extraction exactly where it’s needed.

Ducted subfloor ventilation systems are the only truly effective way to resolve subfloor moisture and air quality issues. By running ductwork directly to problem areas, they remove damp, stale air from even the most enclosed sections of a subfloor — something wall-mounted fans simply can’t achieve. This ensures consistent crossflow ventilation, reduces mould growth, protects structural timbers, and keeps the entire subfloor dry and healthy all year round.

These systems rely on wall-mounted fans, with nothing installed within the subfloor space itself. At Fresh Ventilation, we do not recommend or install wall-mounted subfloor ventilation systems except where there is absolutely no alternative.

Wall-mounted fans have serious limitations. Because they draw air from only one fixed point, they fail to ventilate the entire subfloor — leaving stagnant, damp areas untouched. Without ducting, there is no way to create proper crossflow ventilation, meaning moisture, mould and odours often persist despite the fan running. Many of these units also use small, low-grade axial fans that are noisy, short-lived, and lack the pressure required to move air effectively through complex or divided subfloor spaces.

In situations where physical access under the home is completely blocked, a wall-mounted fan may still provide limited benefit, and this can be better than having no ventilation at all. If this applies to your property, we can advise on the most suitable way to achieve the best possible outcome within those constraints.

While we are firm believers in solar and renewable energy (we have 21 kW of it on our own roof), solar-powered subfloor ventilation fans are simply the worst idea for subfloor ventilation.

Solar subfloor ventilation systems typically use very low-wattage axial fans, which cannot generate enough pressure to move air effectively through ducting or complex subfloor spaces. As a result, airflow drops dramatically once any resistance is introduced, leaving damp and stagnant areas untouched.

They’re also notoriously noisy. On the rare occasions we’ve installed them (against our recommendation), the number one complaint from homeowners has always been the noise. Compounding the issue, these systems rely on low-voltage components that are prone to failure in the harsh, humid conditions found under homes.

And of course, they only operate when the sun is shining — which means on cloudy, overcast, or rainy days, they either run weakly or not at all. Unfortunately, that’s exactly when you need subfloor ventilation the most.

Rising damp is one of the most damaging and misunderstood moisture problems in residential buildings. It occurs when moisture from the ground is drawn up through masonry by capillary action, carrying soluble salts with it. These salts often appear as a white, powdery residue on walls, known as efflorescence, and are a clear indicator of ongoing moisture movement within the structure.

Beyond visible damage, rising damp directly affects indoor air quality. Damp environments with poor ventilation trap moisture-laden air and airborne pollutants, creating conditions that can aggravate asthma, trigger respiratory issues, and cause allergic reactions. One of the most common outcomes of rising damp is mould growth, particularly on internal walls at low levels. As mould develops, it releases spores into the air. Even in otherwise clean homes, these spores can cause sneezing, itchy eyes, runny noses, and other allergy-like symptoms.

Rising damp also poses a serious risk to the structure of the home. Prolonged moisture exposure can weaken masonry, degrade mortar, and compromise the integrity of foundations over time. Metal components such as wall ties, fixings, and supports are also vulnerable, with corrosion accelerating in persistently damp conditions.

Older homes are particularly susceptible. Properties built before the 1980s often lack an effective damp-proof course or were constructed with materials and techniques that do not meet modern moisture-control standards. As a result, moisture can travel freely through brickwork and internal walls, leading to chronic damp issues.

In many cases, the root cause of rising damp is excessive moisture trapped beneath the home combined with insufficient subfloor ventilation. The subfloor area is a common source of ground moisture, whether from natural evaporation, poor drainage, or leaking services. When air beneath the house is stagnant, moisture levels rise and are absorbed into the building fabric above.

This damp environment also creates ideal conditions for pests such as termites, which are attracted to damp timber. Without adequate airflow, timber elements remain moist, increasing the risk of both decay and infestation.

Effective subfloor ventilation addresses these issues at their source. By actively removing moisture-laden air from beneath the home and replacing it with fresh air, subfloor ventilation reduces humidity levels, limits moisture migration into walls, and helps prevent the conditions that allow rising damp to develop.

When properly designed and installed, subfloor ventilation is one of the most effective ways to manage and prevent rising damp. Rather than treating symptoms on internal walls, it tackles the underlying moisture problem beneath the home, protecting air quality, structural integrity, and long-term durability.

Mould growth is one of the most common and visible signs of excess moisture in a home, and it is closely linked to poor subfloor ventilation. Mould thrives in damp, stagnant environments where moisture levels remain high and air movement is limited. Once established, it can spread quickly across walls, floors, timber framing, insulation, and stored materials beneath the home.

In many cases, mould growth inside the living areas of a house originates from below. Moisture trapped in the subfloor raises humidity levels under the home, allowing damp air and mould spores to migrate upward through gaps in flooring, wall cavities, and service penetrations. This often results in mould appearing on internal walls, particularly at lower levels, even when there are no obvious leaks or surface water issues.

Mould is more than just an aesthetic problem. As it grows, it releases microscopic spores into the air. These spores can trigger allergic reactions, aggravate asthma, and cause respiratory irritation, especially in children, the elderly, and those with compromised immune systems. Common symptoms include sneezing, coughing, itchy eyes, headaches, and persistent musty odours that are difficult to eliminate.

From a building perspective, mould feeds on organic materials such as timber, paper linings, and dust. Prolonged mould exposure can lead to timber decay, deterioration of building materials, and ongoing moisture retention, creating a self-perpetuating cycle of dampness.

Effective subfloor ventilation plays a critical role in preventing mould growth. By actively removing moisture-laden air from beneath the home and replacing it with fresh air, subfloor ventilation lowers humidity levels and disrupts the conditions mould needs to survive. Rather than repeatedly cleaning mould from walls and surfaces, addressing moisture at its source — under the house — provides a long-term solution.

When designed correctly, subfloor ventilation not only helps remove existing moisture but also prevents mould from returning, protecting both the health of occupants and the structural integrity of the home.

Musty odours in a home are almost always a sign of trapped moisture and poor airflow, and they commonly originate from the subfloor. These smells are caused by damp air, mould spores, bacteria, and decaying organic material accumulating beneath the house. Once present, musty odours can be persistent and difficult to eliminate using surface treatments alone.

Because warm air naturally rises, odours generated in the subfloor don’t stay under the house. They travel upward through gaps in flooring, wall cavities, service penetrations, and structural joints, eventually entering living spaces. This is why musty smells are often strongest inside the home, even though the underlying problem exists below floor level.

In many cases, homeowners attempt to mask these odours with cleaning products, air fresheners, or dehumidifiers. While this may provide temporary relief, it does not address the source of the smell. As long as damp, stagnant air remains trapped beneath the home, musty odours will continue to return.

Effective subfloor ventilation removes the cause of musty smells rather than treating the symptoms. By actively extracting stale, moisture-laden air and replacing it with fresh outside air, subfloor ventilation reduces humidity levels and removes the odour-producing air at its source.

When properly designed and installed, subfloor ventilation provides continuous air exchange beneath the home, preventing odours from building up and migrating into living areas. The result is a fresher-smelling home and a healthier indoor environment, without the need for ongoing masking or temporary solutions.

Timber decay is a serious and often hidden consequence of prolonged moisture exposure beneath a home. When timber remains damp for extended periods, it creates the ideal conditions for fungal growth, which breaks down the structural fibres of the wood. Over time, this leads to weakening, softening, and eventual failure of timber components.

Subfloor areas are particularly vulnerable to timber decay because they are often dark, poorly ventilated, and exposed to ground moisture. Floor joists, bearers, stumps, and timber framing can absorb moisture from the air or directly from damp soil below. Without adequate airflow, this moisture cannot evaporate, allowing decay to progress unnoticed.

As timber decay advances, it can compromise the structural integrity of the home. Floors may begin to feel spongy or uneven, fixings can loosen, and load-bearing elements may lose strength. In severe cases, extensive repair or replacement of structural timber may be required, which can be costly and disruptive.

Damp timber also attracts pests, particularly termites, which are drawn to moist wood. This combination of decay and infestation significantly increases the risk of serious structural damage.

Effective subfloor ventilation helps prevent timber decay by keeping moisture levels under control. By continuously removing damp air and promoting drying beneath the home, subfloor ventilation reduces the time timber remains wet and interrupts the conditions required for fungal growth.

When designed correctly, subfloor ventilation protects timber elements by keeping them dry, extending their lifespan, and helping preserve the structural integrity of the home.

Termite infestation is a major risk in homes with damp subfloor conditions. Termites are attracted to moisture, and a poorly ventilated subfloor provides the dark, humid environment they prefer. When timber remains damp, it becomes far more vulnerable to termite activity, allowing infestations to establish and spread undetected beneath the home.

Subfloor areas often contain critical structural timber such as bearers, joists, and stumps. When moisture levels are high, these elements are not only more appealing to termites but also harder to inspect. Damp conditions can hide termite mud tunnels and conceal early signs of damage, allowing infestations to progress unnoticed until significant structural harm has occurred.

Excess moisture also weakens timber, making it easier for termites to penetrate and consume. Combined with limited airflow, this creates ideal conditions for rapid termite colonisation and ongoing damage.

Effective subfloor ventilation helps reduce the risk of termite infestation by controlling moisture at its source. By lowering humidity levels and keeping timber dry, subfloor ventilation removes one of the key conditions termites rely on to thrive. Drier subfloor environments are less attractive to termites and easier to inspect, improving the effectiveness of pest management and early detection.

While subfloor ventilation is not a substitute for professional termite treatment or barriers, it plays an important supporting role in protecting the home by reducing moisture-related risk factors that encourage termite activity.

Condensation is a common moisture issue in subfloors and occurs when warm, moisture-laden air comes into contact with cooler surfaces beneath the home. When the air cools, it can no longer hold the same amount of moisture, causing water vapour to condense into liquid on surfaces such as timber, masonry, metal fixings, and insulation.

In poorly ventilated subfloors, condensation can occur regularly, particularly overnight or during cooler periods. This repeated wetting keeps materials damp for extended periods, even when there is no obvious water ingress. Over time, condensation contributes to mould growth, timber decay, corrosion of metal fixings, and increased humidity levels that migrate into the living areas above.

Condensation is especially problematic in homes with limited airflow, shaded subfloors, or areas with suspended concrete slabs and restricted ventilation paths. Because the moisture comes from the air itself, condensation issues are often misunderstood or misdiagnosed as leaks.

Effective subfloor ventilation helps prevent condensation by controlling humidity levels and maintaining consistent air movement. By removing moist air and replacing it with drier outside air, subfloor ventilation reduces the likelihood of air reaching its dew point on subfloor surfaces.

When designed correctly, subfloor ventilation limits condensation, keeps materials dry, and prevents the chain of moisture-related problems that condensation can trigger beneath the home.

Corrosion of metal fixings is another common but often overlooked consequence of excess moisture in the subfloor. When humidity levels remain high, metal components such as nails, screws, brackets, wall ties, stirrups, bearer connections, and support fixings are exposed to constant moisture in the air. Over time, this leads to oxidation and corrosion, particularly in coastal or high-humidity environments.

The subfloor is especially vulnerable because it is typically darker, cooler, and less ventilated than other parts of the home. In these conditions, moisture lingers on metal surfaces, accelerating rust and deterioration. As corrosion progresses, fixings can lose strength, connections can weaken, and critical structural elements may no longer perform as intended.

Corroded fixings not only compromise the structural integrity of the home but can also lead to secondary issues. Timber components may loosen or shift, floors can become uneven or noisy, and structural movement may occur over time. In severe cases, widespread corrosion can necessitate extensive repairs or replacement of fixings and supports.

Effective subfloor ventilation helps prevent corrosion by reducing humidity levels and promoting drying beneath the home. By removing moisture-laden air and maintaining consistent airflow, subfloor ventilation limits the conditions that allow corrosion to occur and slows the rate of deterioration.

When properly designed and installed, subfloor ventilation helps protect both timber and metal components, extending the lifespan of fixings and reducing the risk of hidden structural damage caused by prolonged moisture exposure.

Long-term structural damage is often the end result of unmanaged moisture beneath a home. When damp conditions persist in the subfloor, the effects are not limited to one material or component — they compound over time, impacting timber, masonry, metal fixings, and the overall stability of the structure.

Excess moisture can weaken timber through decay, attract termites, and accelerate corrosion of metal fixings. Masonry walls and foundations can absorb moisture, leading to deterioration of mortar, salt attack, and reduced structural integrity. As these issues progress together, the home may begin to experience movement, cracking, uneven floors, and compromised load-bearing elements.

Because much of this damage occurs out of sight beneath the home, it often goes unnoticed until it becomes severe and costly to repair. What may begin as a damp or musty subfloor can eventually result in major structural works if the underlying moisture problem is not addressed.

Effective subfloor ventilation plays a critical preventative role. By controlling moisture at its source and maintaining consistent airflow beneath the home, subfloor ventilation helps protect all structural elements simultaneously. It reduces the conditions that lead to decay, corrosion, and material breakdown, preserving the strength and durability of the building over time.

When properly designed and installed, subfloor ventilation is not just a solution to existing problems — it is a long-term investment in the structural health of the home, helping to prevent costly repairs and extend the life of the building.

Our most popular configuration, a negative pressure subfloor ventilation system works by extracting more stale, damp air from the subfloor than the amount of fresh air blown in. This creates a gentle vacuum effect, where the space is naturally refilled with fresh outdoor air drawn in through existing vents or openings.

By removing air at controlled locations, this system is highly effective for reducing moisture, musty odours, and mould spores in the subfloor area. It also helps prevent termite risk and wood rot by keeping the environment drier and healthier.

While the drying performance of a negative pressure setup can be slightly slower than a positive pressure system, it provides consistent results and remains the preferred choice for many Australian homes.

Negative pressure subfloor ventilation is our preferred approach and is widely regarded as the safest and most reliable option for most Australian homes. By continuously extracting damp, stale air from beneath the house, the system creates a controlled vacuum that draws fresh outdoor air in and ensures strong, predictable cross-flow ventilation. This negative pressure makes it virtually impossible for moisture or odours to rise into the living areas above, instead giving complete control over where dampness and mustiness are removed.

Unlike positive pressure systems, negative pressure subfloor ventilation does not rely on passive venting to expel moisture. The result is guaranteed moisture reduction, consistent airflow in all weather conditions, and long-term protection against mould, mildew, and termite risk. For these reasons, negative pressure subfloor ventilation is the preferred choice of pest inspectors, builders, and homeowners seeking a proven, effective solution for a drier, healthier subfloor environment.

A positive pressure subfloor ventilation system works in the opposite way to negative pressure. Instead of extracting stale air, this configuration uses mechanical ventilation to blow a greater volume of fresh outdoor air into the subfloor, which in turn forces damp, polluted air out through existing vents or openings.

Because dry air is constantly circulated across damp surfaces, positive pressure systems can be highly effective at drying out subfloor moisture, mould, and condensation. In fact, this setup is often faster at reducing dampness than trying to simply extract moist air from wet surfaces.

However, care must be taken to ensure there is sufficient passive venting or outlets for the displaced damp air to escape outdoors. Without adequate venting, moisture may rise into the home above, leading to condensation, musty odours, or mould problems inside.

A balanced pressure subfloor ventilation system combines both positive and negative pressure by supplying fresh outdoor air into the subfloor while simultaneously extracting stale, moisture-laden air at an equal rate. In theory, this creates a neutral or “balanced” pressure environment, with the same volume of air entering and leaving the space.

While this approach can sound like the best of both worlds, balanced pressure systems require extreme care and attention to detail to work effectively. Because the pressure within the subfloor is not reduced, there is no inherent safeguard preventing air movement from the subfloor into the living areas above. This means damp air or odours can still migrate upward if the system is not perfectly designed.

Balanced pressure systems are typically only appropriate where the subfloor is relatively airtight and has very limited or no natural openings for make-up air to enter. In most Australian subfloors — which often have vents, gaps, and variable leakage paths — balanced systems can behave unpredictably.

Another key challenge is airflow short-circuiting. With one fan supplying air and another extracting it, air naturally takes the path of least resistance and can move directly between the two fans, bypassing large sections of the subfloor. Without careful layout and airflow control, this can leave pockets of stagnant air untouched.

For these reasons, balanced pressure systems demand professional design and precise fan placement to ensure adequate coverage and effective moisture control. They are not forgiving of layout errors, and poor design can result in uneven ventilation and reduced performance.

Where supply air is desired alongside extraction, a more reliable approach is often to use three fans rather than two — for example, one supplying fresh air and two extracting. This configuration maintains the benefits of introducing fresh air while creating an overall negative pressure bias, ensuring strong cross-flow ventilation and preventing damp air or odours from rising into the home. It also reduces the risk of airflow short-circuiting and provides all the safety and reliability advantages of a negative pressure system.

In practice, this negative-biased approach delivers more predictable airflow, better moisture control, and greater long-term protection for the subfloor and the home above.

Mechanical subfloor ventilation uses a powered fan to actively move air through the subfloor space. This is fundamentally different from passive subfloor ventilation, which relies on natural airflow through gaps and openings in the external walls.

Passive subfloor ventilation includes weep holes, terracotta vents, wire mesh vents, air bricks, and access doors. While these openings allow air to enter and exit the subfloor, they do not guarantee that air will actually move or be exchanged in a meaningful way. Airflow depends entirely on wind direction, pressure differences, and external conditions, all of which are unpredictable.

When a subfloor has a mould or damp problem, passive ventilation is almost always ineffective. Moisture issues occur precisely because air is not moving or being replaced. Simply having openings does not ensure stale, moisture-laden air is removed from the space.

Cross-flow ventilation — where fresh air enters the subfloor and stale air is actively drawn out from another location — is nearly impossible to achieve without mechanical ventilation. Air is lazy and will always take the path of least resistance. If air does enter a subfloor through a passive vent, it is far more likely to exit again through the nearest large opening rather than travel around corners, under walls, or into smaller, enclosed sections of the subfloor.

Mechanical ventilation changes this completely. By actively extracting stale air from problem areas and enclosed sections, the system forces air movement throughout the entire subfloor. This creates true cross-flow ventilation.

Airflow is measured in cubic metres per hour (m³/h). For every cubic metre of stale air that is mechanically extracted, one cubic metre of fresh air must enter the subfloor to replace it. This principle — air out equals air in — ensures continuous air exchange. As the fans run, fresh air is drawn in through existing vents and openings and is pulled through the subfloor space towards the extraction points.

The result is consistent, controlled airflow that removes moisture-laden air, reduces condensation risk, and helps prevent mould growth. Mechanical subfloor ventilation does not rely on weather conditions or chance — it delivers reliable performance every day, regardless of wind, temperature, or humidity.

In short, if moisture, mould, or stagnant air is present, mechanical subfloor ventilation is the only reliable way to properly ventilate the space and protect the structure of the home.

The performance of a subfloor ventilation system depends heavily on duct layout. Even with the right fans, poor duct placement can leave stagnant areas and reduce overall effectiveness. For this reason, every subfloor ventilation system we supply is custom-designed for the specific home, rather than treated as a one-size-fits-all solution.

Information we consider includes:

• The age of the home and its construction style
• Rough measurements or external dimensions
• The location of the subfloor access point
• External walls with space to install aluminium exhaust grilles
• Any preferred locations for exhaust grilles
• The locations of existing openings or passive vents
• Walls where natural ventilation is restricted by concrete slabs or adjacent structures
• Whether the subfloor is an open space on piers or divided into multiple compartments
• Subfloor height, including any changes in height
• Known problem areas in the subfloor or in rooms above
• The fall of the surrounding land
• Frequently used outdoor areas such as patios, BBQ areas, or clothes lines

Using this information, we design a duct layout that targets problem areas, avoids unnecessary restrictions, limits inefficient fan splitting, and positions extraction points to create effective cross-flow ventilation. The result is a system that moves air where it’s actually needed, rather than relying on guesswork.

Our goal is to ensure your system is designed correctly before installation begins, so it works properly from day one and continues to protect your home long term.

Choosing between an EC motor and an AC motor subfloor ventilation system comes down to how much control, efficiency, and flexibility you want from the system, as well as how the subfloor will be used over time. Both options are effective when correctly designed, but they suit different applications and priorities.

AC Motor Subfloor Ventilation Systems

AC motor systems are a robust, cost-effective solution that deliver reliable, consistent airflow. AC motors operate at a single fixed speed, which is typically their most efficient operating point. This makes them well suited to applications where the subfloor requires a known, steady level of ventilation and where simplicity is preferred.

AC centrifugal fans are quiet in ducted applications, move large volumes of air, and provide excellent performance for both maintenance ventilation and active moisture control when sized correctly. Because of their simplicity, AC motor systems are also easy to commission and operate with minimal adjustment.

EC Motor Subfloor Ventilation Systems

EC motor systems offer a higher level of performance and control. EC motors feature fully variable speed operation, allowing airflow to be precisely matched to the size, layout, and moisture conditions of the subfloor. This makes them ideal for homes where conditions may change over time or where fine tuning is important.

In real-world operation, EC motors are extremely quiet, particularly when run at reduced speeds. They are capable of near-silent operation while consuming very little power, making them well suited to noise-sensitive environments or systems designed to run for longer periods each day. EC motors also maintain high efficiency across their entire speed range, not just at full output.

When to Choose Each Option

An AC motor system is often the right choice when:

• You want a proven, cost-effective system with fixed, predictable performance
• The subfloor conditions are well understood and unlikely to change
• Simplicity and value are the priority

An EC motor system is often the better choice when:

• You want the ability to fine-tune airflow or adjust performance over time
• Noise minimisation is a key consideration
• Long daily run times and low operating costs are important
• You want a more future-proof system with greater flexibility

Our Approach

Regardless of motor type, the most important factor is correct system design. Fan quantity, duct layout, extraction points, and airflow targets all matter more than the motor alone. We offer both AC and EC motor subfloor ventilation systems because different homes require different solutions, and we size and configure each system to ensure it performs as intended.

If you’re unsure which option is best for your home, we can assess your subfloor layout, moisture levels, and usage requirements and recommend the most suitable system.

The most common mistake we see during installation is getting the layout wrong. Many people overcomplicate the system without first considering the most important principle of ventilation: replacement air.

Ventilation only works if air can both leave and enter a space. Put simply: air out = air in. If stale air is being extracted, fresh air will enter the subfloor to replace it. Ignoring where this replacement air comes from is the root cause of most poorly performing systems.

A common example helps illustrate this. Imagine a simple, rectangular subfloor with passive vents evenly spaced around the entire perimeter. A very common mistake is placing extraction points near each corner, with the assumption that this provides maximum coverage. In reality, this does the opposite. Air is drawn in through the nearest external vents and extracted almost immediately, meaning most of the subfloor space in between sees little to no airflow.

In this scenario, the most effective layout would place extraction points zig-zagged down the centre of the subfloor. This forces air to enter from opposing sides and travel across the space, creating genuine cross-flow ventilation and ensuring the entire area is ventilated.

Real-world subfloors are rarely this simple. We regularly see far more complex situations, including:

• L-shaped buildings
• Homes with passive vents on some walls but not others
• Homes with too many passive vents, making controlled ventilation more difficult
• Subfloors affected by surface water run-off
• Walls where airflow is blocked by adjacent structures or concrete slabs
• Garages or extensions attached to part of the home
• Subfloors with too much natural airflow, making controlled ventilation more difficult

In these situations, copying a generic layout or guessing extraction locations almost always leads to poor results. Each subfloor behaves differently, and effective ventilation depends on understanding how air will actually move through the space.

This is why professional design assistance is so valuable. A well-designed layout considers replacement air, natural restrictions, moisture sources, and airflow paths before a single duct is installed. Getting this right at the design stage is the difference between a system that simply runs and a system that actually works.

Decibel ratings are often misunderstood and, in many cases, misused. On their own, dB figures rarely reflect how loud a fan will actually sound once installed in a real building. Unfortunately, some manufacturers take advantage of this by publishing selectively measured or unrealistic noise figures that do not represent real-world performance. Some manufacturers are simply dishonest. Please see our Instagram post HERE and our Instagram video HERE for a good explanation of the issue.

Firstly, decibel ratings are typically measured under laboratory conditions that bear little resemblance to an installed environment. Measurements may be taken at unrealistic distances, at reduced fan speeds, without ducting attached, or in free-air test rigs. This makes it very easy to publish an impressive number that does not translate to real installations in homes.

Secondly, not all noise is perceived equally. The frequency of the sound (its pitch) is often far more important than the overall decibel level. Many fans with low published dB ratings produce a noticeable high-frequency motor “whine”. This type of noise travels easily through building materials and is particularly intrusive to occupants. By contrast, our centrifugal fans predominantly generate airflow noise rather than motor noise. Once installed, airflow noise is largely attenuated by ducting on either side of the fan, while motor whine continues to transmit through structures.

Thirdly, decibel scales are logarithmic, not linear. A small numerical difference in dB can represent a significant perceived difference in loudness, yet manufacturers often quote figures without context or explanation. This makes side-by-side comparisons meaningless unless the test methods are identical and independently verified.

We have been installing subfloor ventilation systems for over 15 years and have tested virtually every fan available on the market, including all major competing models. Based on extensive real-world installation experience, we are confident that our fans are quieter in installed conditions than any comparable models currently available.

Importantly, our decibel ratings have been independently tested in Australia by VIPAC Engineers & Scientists Ltd, providing credible, third-party verification rather than marketing-driven claims.

For a clear visual explanation of why published noise figures can be misleading, we recommend viewing our Instagram videos linked above, which break this issue down in simple, practical terms.

In summary, decibel ratings alone do not tell the full story. Installation method, operating speed, sound frequency, fan design, ducting, and vibration isolation all have a greater impact on perceived noise than a single dB number. This is why real-world performance and proven installation experience matter far more than headline specifications.

Yes. Our fans have been independently tested and certified for Australian electrical safety compliance. They carry the Regulatory Compliance Mark (RCM), confirming they meet the relevant Australian Standards and are registered under the Electrical Equipment Safety System (EESS) for legal sale and safe use in Australia.

All testing and certification was conducted by VIPAC Engineers & Scientists Ltd, an accredited independent testing authority. This provides assurance that our fans meet strict Australian requirements for electrical safety, performance, and compliance, giving you confidence that the equipment is safe, reliable, and approved for use in Australian homes.

For residential electrical installations in Australia, fan motors are required to be manual restart as part of meeting safety expectations under the Regulatory Compliance Mark (RCM) framework.

In this context, manual restart refers to how a motor behaves when a fault is detected, such as overheating or internal electrical failure. A manual restart motor shuts down and remains off once a fault occurs. The motor must then be repaired or replaced before it can operate again. This behaviour is intentional and forms a critical safety mechanism, preventing continued operation of a faulty appliance.

By contrast, auto restart motors are designed to stop temporarily when a fault is detected and then automatically attempt to restart after a delay. If the underlying fault remains, the motor can repeatedly stop and restart. This fault-cycling behaviour significantly increases electrical stress and heat build-up and may cause a fire.

Australian residential electrical safety requirements are deliberately conservative in this regard. The expectation is that appliances installed in homes should not repeatedly re-energise themselves after a fault, as this presents an unacceptable fire risk.

Many fans available on the Australian market are nevertheless auto restart. This is largely because they are designed for overseas markets where this requirement does not exist. Australia represents a very small portion of the global fan market, and many manufacturers simply supply globally standard products that are compliant elsewhere but not appropriately configured for Australian residential use. In many cases, this distinction is not clearly disclosed.

Based on our understanding of the local market, we believe our fans are among the very few available in Australia that are genuinely manual restart, specifically selected and configured to meet Australian residential electrical compliance expectations under RCM.

This is not a marketing feature — it is a safety requirement. And it is one that is often overlooked.

We are strong supporters of solar energy and use it extensively ourselves — including a 21 kW solar system on our own roof. However, despite the benefits of solar in many applications, solar-powered subfloor ventilation fans are not effective, which is why we do not sell or install them.

Solar subfloor ventilation systems rely on very low-wattage axial fans. Axial fans perform poorly when any pressure or resistance is introduced. As soon as ducting is added — which is essential for effective subfloor ventilation — airflow drops dramatically. In real installations, this results in very low and inconsistent air movement.

Noise is another major issue. On the numerous occasions we have installed solar subfloor fans at a client’s request (against our recommendation), the most common and consistent complaint has been excessive noise. The fan tone is often high-pitched and intrusive, particularly when mounted directly to walls or vents.

Performance also depends entirely on direct sunlight. On cloudy, overcast, or rainy days, solar subfloor fans either perform very poorly or do not operate at all. Unfortunately, these are exactly the conditions when effective subfloor ventilation is most important, as moisture levels are typically highest.

In short, while solar power itself is highly effective, solar-powered subfloor ventilation fans do not deliver reliable, consistent, or effective ventilation. We focus on systems that work every day, in all conditions, and provide predictable airflow and moisture control — not just when the sun is shining.

For these reasons, we choose not to sell or install solar subfloor ventilation fans.