Effective Ventilation

Everyone knows how important ventilation is, and most people understand how critical it is that we use ventilation when required. But sometimes standard practice just is not enough.

The key areas in a home that need sufficient ventilation are:

• Bathroom
• Toilet and
• Kitchen

In this article, we are primarily talking about bathroom and toilet ventilation, highlighting scenarios where existing systems underperform due to design flaws or operational misuse.

The first thing, and probably the most important aspect, that can help the effectiveness of ventilation is to ensure that the fan installed has a readily available source of air.  Bathrooms and toilets are usually small rooms, with doors most often closed when ventilation is needed.  Natural air gaps in a standard bathroom at the bottom of the door or through cracks is not nearly large enough of an opening to allow air in, resulting in a fan performance reduction of up to 30%-40%.

Diagram 2 illustrates how an airtight bathroom/toilet, hampers the performance of ventilation.

Tests undertaken by Efficiency Matrix in a small bathroom found that an extraction fan operating with a door open moved 78 L/s compared to 45 L/s with the door closed.

The one sure way to fix this is to install a door grill in your bathroom/toilet door. Then, whenever a ventilation fan is turned on, it can leverage air leaks throughout the whole building in order to draw enough air straight to the extraction fan. Installing a door grill available from Tighthouse enabled the fan to move 75l/s. The air supply should be placed strategically such that the source of the odour is between the extraction point and the supply. This may mean placing the vent close to the ground so that air passes through the room up to the roof.

There is a significant difference between Diagram’s 1 and 3, Diagram 1 will produce the best outcome.

Draught stoppers are also a great idea. By reducing air leakage, your bathroom can maintain a warmer temperature during winter. This is turn prevents air from reaching the dew point and causing mould in your home.

Diagram 4 shows how an over ventilated bathroom is not effective either and is especially problematic for humidity and mould control.