Sub-Floor Ventilation and the City (Melbourne, Sydney, Brisbane) – Is it a Good Idea?

In the cities such as Melbourne, Sydney or Brisbane, land-space is maximised by reducing block sizes and opting for medium to high density dwellings. This creates a challenge for effective sub-floor ventilation where surrounding buildings can inhibit natural air-flow through passive vents or neighbours being in such close proximity that the noise (or db rating) from certain types of fan-forced ventilation systems can be quite disturbing.

In one case, Envirofan received a phone call from a potential customer who had installed a competitors 150mm sub-floor ventilation system in Neutral Bay, Sudney. A complaint had been made to council regarding the noise from the system and the client was eager to swap these out for a quieter solution.

Unfortunately, there are a number of competitors with ‘noisy’ products in the market – ranging between 47 and 59 db@1m – almost doubling our own EF10-4 Quad Fan at only 27db@1m. Builders may typically opt for a noisier system in an attempt to cut costs but at the expense of the result; the customer who is left with the constant disruptive sound, complaints, and ultimately the cost of swapping the system for a much quieter one.

EF10-4-S2R-150Upon further inspection, Envirofan also found that while the ‘noisy’ 150mm system could allow for further ducting, there was adequate sub-floor space available for a better cul-de-sac ventilation solution. 150mm systems are generally installed to allow for ducting to be attached to the rear spigot. This typically ventilates a sub-floor area enclosed on two or three sides where the ground may be nearly, or as high, as the internal floor level (where a brick-sized vent cannot be fiited). However if there is adequate crawl space in the sub-floor area then a better alternative can be used – Envirofan’s ‘Cul-De-Sac Ventilation’ with half the db (noise) rating at only 27db@1m (pictured).

Also, should the singular 150mm fan have ceased, 100% of the ventilation properties would be immediately lost. Where Envirofan’s cul-de-sac ventilation system has four small fans catering for the failure of an individual fan – only 25% of the air flow would be lost, 75% would continue to extract damp air.

Finally, the Envirofan cul-de-sac ventilation systems are mounted from the floor joist at the problem area.

Worst case scenario, if there is not adequate crawl-space beneath the dwelling, 150mm sub-floor ventilation systems are the norm. We recommend talking to your installer about the noise transfer of these systems to your neighbours. They may be able to turn down the pitch of the motor via a variable voltage controller but keep in mind, this will reduce the effectiveness of the machine.

Because if its containment within the sub-floor area, its low db rating, Envirofan’s cul-de-sac ventilation solution is ideal for medium to high density dwellings. Contact us today to find out more or to find a installer/re-seller close to you!