We are dealing with humidity and radon issues in our basement. Even though we have a dehumidifier, we wanted to install an exhaust fan to vent the air in the basement, hoping that it will also reduce radon. This blog is not about providing a definitive solution to deal with humidity and radon but rather a measure we took to see if it helps. Here’s how to install an inline exhaust fan in a basement for ventilation.
This DIY is very easy, budget friendly and you need only a handful of materials and tools.
Tools and materials you need:
- Inline Booster Duct Fan : We chose this 4″ fan that is usually used as blower fan for HVAC. Also, it has speed controller.
- Wall Vent Hood: You can find this any home improvement store (its cheaper than amazon). Buy the one that comes along with 4″ duct and vent hood in color to match your exterior wall.
- Power drill
- 4″ hole saw: You can buy as a set or individual. I recommend buying from a good brand. I had a hole saw set bought from amazon for a cheaper price from an unknown brand. It worked fine but took out all the patience in me. It gets blunt and hot quickly.
- Measuring tape
- Long predrill bit
- Spray insulation can
- Outdoor waterproof caulk
- Power outlet inside your basement near the vent
Another option we have seen people using is a ventilation fan that can be installed directly on the basement wall. We did not use it because of the limited pace we have. If you think you have enough space, then you should try this fan.
How to install inline exhaust fan in basement for ventilation?
Choose the right spot:
Find the type of construction have in your basement and locate a place where the wall is above the ground and clear of all other services. In our basement, we have concrete block walls partly inground and only about 6 to 8″ above ground where the wooden framework for the whole house starts. Most of that space were occupied by other services and we found one area feasible for us.
Tip: Do not choose a spot close to a window or near a supply vent. When you turn on the exhaust fan, it will only suck out the fresh air.
Pre-drill and make 4″ dia hole:
Since it’s an exterior wall, it will be packed with insulation. So, wear gloves and remove the insulation. I found the center and made sure I had enough space to drill a 4″ hole. To identify the exact location from the outside, take a long drill bit with minimal thickness and drill from the inside to see where it comes out. With this identification, you can move a couple of inches to the right or left if needed. Once the spot is confirmed, use a 4″ diameter hole saw to drill from the inside. If you have vinyl siding like mine, drilling all the way from the inside can push the siding out. So, once you have drilled halfway from the inside, drill from the outside using the pilot hole.
Install vent:
Insert the duct attached to the vent hood into the hole from the outside. If it fits well, install the screws for the vent hood. You will need long screws for this installation. Finally, apply silicone caulk to seal and waterproof the gaps.
Install inline fan:
From the inside, connect the inline fan to the 4″ duct end. Identify the airflow direction in the fan and connect the side that needs to vent the air out. Install a brace to the ceiling joist to hold the vent and duct if needed. Once installed, connect the fan to the nearest power outlet. Optionally, you can also connect a duct extension to direct the air out from a specific space.
Finally, seal the gaps around the 4″ hole from inside with the spray foam. Once it dries, put the pink insulation back around the duct.
That’s it!. Its an easy installation.
Conclusion:
How to Install an Inline Vent in Your Basement for Ventilation: Is It Helping with Humidity and Radon?
We installed the inline vent in April, 2024. It’s only been a couple of months since the installation, so we can’t say definitively if it works yet. However, we always monitor the readings for humidity, temperature, and radon with a sensor. We turn on the fan every morning and also the windows in the basement and turn off before going to bed. It appears to be helping a bit by reducing humidity and radon levels, but we cannot guarantee the results at this point. We’ll continue to monitor and provide updates on its effectiveness over time.