I have a second floor bathroom that has a ventilation fan which exits to the roof. Whenever I take a shower there is an incredible amount of freezing air (midwest winter) that is coming in through the bathroom fan (not running because the bathroom door is open). How can I prevent this? The simple solution would seem like just turning the fan on but there is still a really cold draft that whirls about the shower area (enclosed shower stall with open top).
How to prevent reverse air flow from bathroom fan
bathroom-fixturesventilation
Related Solutions
If it's a really old house, that might actually work to your benefit as old houses usually are not well sealed when compared to new homes which are practically air tight.
There's a couple components to what you are trying to accomplish:
- Air circulation - A ceiling fan will probably do the trick for a single room. If the house is conditioned via forced air, another option might be setting the furnace fan to be always on instead of only on when heating/cooling. This will help keep the air circulating throughout the house (and through the furnaces filter).
- Humidity - If its really bad, a dehumidifier will likely be required.
- Fresh air - In all likelihood, you are probably getting a decent amount of fresh air through the cracks in the walls and elsewhere already (seeing as it's an old house). If you are not, the simplest solution is to open a window ocasionally. If this is not an option (ie: winter) then the furnace fan trick I mentioned in (1) migtht help too.
Some other options are:
- Some household plants might also help with the air quality - talk to your local garden center to see if they have any ideas
- Air ioniser (or negative ion generator) - I can't backup any claims made by these devices, but some people claim they work well.
- Install a small HEPA filter
I realize that this is a U.S. reference, but you may be able to find a wall exhaust fan locally similar to this.
You need to find a unit that is intended for exposure to the outdoors. Also you may need a cover in the colder months if the unit you find does not have a self closing louver. The one depicted does.
If you use 110 voltage and 60cycles, you may be able to order something like this from the U.S. Otherwise, be sure that it matches your local electric supply.
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Best Answer
Your fan is equipped with a backflow prevention flap. Check that it's installed correctly and not gunked up with so much lint that it doesn't function.
It's usually a simple task to remove the cover, unplug the fan and light, and drop the motor panel. This usually doesn't require work on the wiring connections. From there you have open access to the flap.