Damp under a house causes real problems. It leads to musty smells, mould, timber decay and pests, and it can affect the air quality inside your home. A sub-floor ventilation fan pulls moist air out of the space under your floor so it stays drier. The catch with many of these fans is noise, especially if the crawl space sits under a bedroom or living area.
The Blauberg Iso-Mix Silent Sub-Floor Ventilation Kit 1 from Vent Experts is built for small spaces where noise matters. It is a complete kit for sub-floor areas up to 50 cubic metres. This review covers what you get, how it works, what to check before buying, and who it suits.
Quick summary
| Detail | Blauberg Iso-Mix Silent Sub-Floor Ventilation Kit 1 |
|---|---|
| Suits | sub-floor spaces up to 50m³ |
| Fan | Blauberg Iso-Mix 150mm sound insulated fan |
| Airflow | 323 CFM (about 550 m³/h), with 2 speeds |
| Setup | single intake, so one point where air is drawn from under the floor |
| Includes | fan, grilles, ducting, clamps, hanging strap and a digital timer |
| Price | $759.95 (reduced from $801.95) |
| Sold by | Vent Experts, with delivery across Australia and Click & Collect from Lidcombe |
What is in the box
This is a full kit, which is a big part of its appeal. You do not need to piece together parts from different suppliers. The box includes:
- 1 x Blauberg Iso-Mix sound insulated fan, 150mm, 323 CFM, 2 speed
- 1 x Fantech external fixed louvre grille, 150mm, for the outside wall
- 1 x Fantech IDJG ceiling mounted internal grille, 200mm, for the intake
- 2 x black PVC coated dual layer flexible ducts, 5 metres each, 152mm
- 4 x quick fit stainless steel duct clamps, 152mm
- 1 x duct hanging strap tape, 25mm x 50m
- 1 x Mojo Cow Time-R digital timer
The kit is matched, so the duct sizes, clamps and grilles fit together. That saves you the guesswork that often comes with ventilation jobs, where one wrong size means a second trip to the shop.
The 10 metres of total ducting is worth thinking about. It gives you room to place the fan away from the intake and run the duct to an outside wall. If your run is longer than that, you will need to buy extra duct.
How it works
The idea is simple. The fan sits in the sub-floor space, connected by duct to the internal intake grille and to the external louvre grille on the outside wall. When the fan runs, it draws damp air from under the floor and pushes it outside. Fresh, drier air then flows in through the existing sub-floor vents to take its place.
That last part is easy to miss. A fan can only move air out if air can get in. Before you install any sub-floor fan, check that your existing vents are open and not blocked by garden beds, mulch, paving or stored items. If the space cannot breathe in, the fan will struggle and may do little to reduce the damp.
Performance and noise
The fan
The Iso-Mix is a mixed flow inline fan with acoustic lining built into the housing. It moves 323 CFM, which is about 550 cubic metres of air per hour. Against a 50m³ space, that is a lot of airflow on paper. In real installations the actual figure will be lower, because ducts, bends and grilles all slow the air down. Even so, there is a good buffer for a small sub-floor.
The two speed settings are handy. You can run the fan on a lower speed for regular use and switch to high when the space is very damp, for example after heavy rain.
Noise
This is the main reason to choose the Iso-Mix over a standard fan. The sound insulation is aimed at homes where the fan sits under bedrooms or living areas. A standard inline fan can be heard as a hum through the floor. The insulated design should keep that much lower.
To be fair, no fan is completely silent, and how much you hear depends on how well it is installed. A few things make a real difference:
- Hang the fan from the strap so it does not touch the floor joists or bearers. Contact with timber carries vibration through the house.
- Keep the flexible duct as straight as you can, because tight bends add airflow noise.
- Place the fan away from the spot directly below your bed, if the layout allows it.
The timer
The included Mojo Cow Time-R timer lets you set the fan to run at chosen times instead of running all day. You can pick hours, minutes or seconds of operation per cycle. This has two benefits. It cuts electricity use, and it keeps noise to the times when you are least likely to notice it.
A common approach is to run the fan for a few hours a day, spread across cooler parts of the day, then adjust based on how dry the space feels. Your ideal schedule will depend on your climate, soil and how damp the space is to begin with.
Build quality and materials
The ducting is dual layer and PVC coated. The product page says it resists mould, corrosion and UV damage, which suits a damp, dark space. The clamps are stainless steel, so they should not rust in humid conditions. That is a small detail, but rusted clamps are a common failure point in sub-floor installs.
The external grille is a Fantech fixed louvre, designed to keep weather out while letting air pass. The internal grille is an adjustable ceiling mounted type, which makes it easier to position the intake where you want it. Browse more external vents if you need a different outside grille.
Fantech and Blauberg are both established names in ventilation, and using their parts gives you some confidence that spares and support will be available later.
Pros and cons
✓ What we like
- Complete kit with everything needed for a standard install
- Sound insulated fan, well suited to under-bedroom or living area spaces
- Two speed settings for flexibility
- Programmable timer included, so no extra purchase
- Moisture-resistant ducting and stainless steel clamps
- Currently discounted from the usual price
✗ What to keep in mind
- It only covers spaces up to 50m³, so larger sub-floors need a bigger kit or more than one
- Single intake means one extraction point, which works best in simple, open spaces
- If your sub-floor is divided into sections by brick walls, air may not move between them, and a single intake may not reach every section
- Long or complicated duct runs need extra duct and will reduce performance
- Electrical connection should be done by a licensed electrician in Australia
Who should buy it
This kit is a good match if:
- ✓ You have a small crawl space or sub-floor under 50m³
- ✓ The sub-floor sits under a bedroom, living room or other quiet area
- ✓ You want an all-in-one kit for a DIY or tradie install
- ✓ You have signs of damp such as a musty smell, condensation or mould on timber
It is probably not the right pick if your sub-floor is large, split into many sections, or if you need several extraction points. In that case, look at the larger kits in the Vent Experts sub-floor range.
How to work out your sub-floor size
Before you order, check that your space is 50m³ or less. The calculation is simple:
- Measure the length of the sub-floor in metres.
- Measure the width in metres.
- Measure the average height from the ground to the underside of the floor.
- Multiply all three numbers together.
For example, a space that is 8 metres long, 5 metres wide and 1 metre high is 40m³. That fits within this kit. If you land close to 50m³, or the space has separate sections, ask Vent Experts for advice before buying.
Final verdict
The Blauberg Iso-Mix Silent Sub-Floor Ventilation Kit 1 does one job and does it sensibly. It gives small sub-floor spaces a quiet, effective way to get rid of damp air, and it comes with the parts and timer you need to get started. The sound insulated fan is the main selling point, and it matters most in homes where the fan sits close to living areas.
At $759.95 it is not the cheapest way to ventilate a sub-floor, but you are paying for low noise and a full kit rather than a bare fan. If your space fits within 50m³ and you care about noise, it is a solid choice.
Buy the Blauberg Iso-Mix Sub-Floor Kit 1 in Australia
If damp, musty air under your floor is a problem and noise matters, this complete kit gives you everything needed for a quiet sub-floor ventilation install.
Vent Experts Australia - view the Blauberg Iso-Mix Silent Sub-Floor Ventilation Kit 1 for $759.95 (reduced from $801.95), with delivery across Australia and Click & Collect from Lidcombe.
Visit our website to check stock and get advice on your sub-floor today.
Frequently Asked Questions
It is designed for sub-floor spaces up to 50 cubic metres. Multiply the length, width and average height of your space to check. If you are near the limit or have a divided space, get advice first.
The Iso-Mix has acoustic insulation built into the housing, so it is much quieter than a standard inline fan. It is not silent, so how you hang it and route the duct will affect what you hear inside the house.
In Australia, fixed wiring should be done by a licensed electrician, so plan for that part of the job.
There is no single answer. It depends on your climate, how damp the space is, and how well air can flow in through existing vents. Start with a few hours a day using the timer, then adjust based on results.
For most standard installs, no. The kit includes the fan, grilles, ducting, clamps, hanging strap and timer. You may need extra duct for longer runs, and you will need electrical work to connect the fan to power.