These aluminum sidewall trailer vents are great alternative, or addition, to a roof vent. These particular vents are bi-directional, meaning you can open them to the front or rear. This is great so you can ram air in one vent while you’re driving and exhaust from the other. By putting one vent low and one vent high, you’ll also generate some natural convection in the trailer while the trailer is sitting. Good ventilation is a huge part of ridding your trailer from excess moisture, which will lead to condensation. Good ventilation also helps rid the trailer of harmful fumes like exhaust smoke and carbon monoxide.