There is a plastic pipe that is exactly next to my window, and whenever the neighbour has a shower (which seems to happen a lot, throughout the day and untill 12 or 1 am at night) it just blows hot air from it and it is really loud. I took a picture of it so you can see. I also went outside my window today and looked at it closely. It is a plastic pipe, hot air is coming out, and I was wondering there must be a way to make it be more quiet? Something simple? That I could put around it, or on the end? Something? Please help as I am really annoyed by the sound. There must be someone who knows what to do with it. :)
It's a direct-vent (a.k.a. powervent) water heater exhaust. My home has the same thing. The first night I slept there it about knocked me out of bed, and now we usually keep the window closed on that side.
You can find duct mufflers that will dramatically reduce the noise, but they're something you'd need to work with your property owner to install safely and according to building and rental codes. You're dealing with carbon monoxide, so you don't want to take risks.
Another option might be to route the pipe up the wall and above the roofline, or simply to direct the opening away from windows. Again, this would require homeowner approval and assistance, and you need to prevent rainwater intrusion.