Why Is My Bathroom Stuffy?

You’ve finished your morning shower but the steam is still floating around your bathroom. It’s fogged up the mirror, your walls are dripping with condensation and it’s hard to breath.

Most bathroom fans, despite the noise they generate, don’t provide the adequate ventilation needed to purge the steam from your bathroom – but it doesn’t have to be that way.


Why does this happen?

Recent times have been a race to insulate homes. Insulation is a great cause. However, insulation without ventilation can have dire consequences for the home and your health.

Traditionally, a poorly insulated home meant that water vapour, fumes, pollutants and smells could simply escape through the cracks of the home. Therefore whilst poorly insulated, they were well ventilated.

Today, with properly insulated homes, rooms don’t receive enough air changes per hour to maintain a breathable environment.


What’s bathroom fans got to do with anything?

In bathrooms, builders simply install cheap and noisy air extraction fans in bathrooms. This is to offset the knock on effects of insulation, sucking water vapour from the bathroom into the roof space. This hot air needs to be removed from the roof space. Putting poor ol' pressure on your passive whirlybird.

But the problem doesn't end there. These cheap air extractions move air at 3L/sec. Not 5L/sec as advertised. So an average bathroom (3mx3mx3m)  equates to 27 000 litres. That would require 9000 seconds (1hr 30mins) to change all the air in the bathroom. Assuming you have a whirlybird installed and adequate ventilation to replace the moist air that has been drawn out.

3L/sec is best case scenario. Without adequate ventilation, stress is put onto the fan and efficiency will be even lower.

Given that most bathroom extractor fans tend to be switch on when you turn the bathroom light on and then run for 5-10 minutes after the light is switched off it’s not hard to see that you’ve very little chance of getting rid of the moisture laden air unless you leave the light on for an hour or so after your shower.

I accept there are methods for calculating what size of extractor fan to install (Very similar to the calculation used above). But in my experience most people simply go down to the builders suppliers and pick up a standard off the shelf extractor fan and have it installed. 

What Can You Do About It?

  1. Negative Pressure Ventilation
    A SolarWhiz can be installed in your roof and equipped with ducting. This not only evacuates hot, moist air from your roof space but also your bathroom. It works by installing a vent in the room, which ducts the air directly into the SolarWhiz to be evacuated outside. It's silent and will keep your room fresh.

  2. Positive Pressure Ventilation
    Additionally, a SolarVenti can push dehumidified air back into your home, replacing the air that's been exhausted through negative pressure. This will dehumidify your home and work to keep bacteria at bay.


If you have concerns about the levels of condensation in your bathroom or if you’ve got mould in your bathroom. Then your bathroom extractor fans simply aren’t up to the task and you should give serious consideration to one of the above products.

If you’re on the fence, Google the health concerns of mould to see why you really don’t want it in your home.