If your home has a passive radon pipe running through the attic, converting it to an active system is often as simple as adding a fan there. The attic is usually the ideal location. This guide explains how the fan is placed, how it gets power, and what to check afterward.
How is a passive radon system converted with an attic fan?
To convert a passive radon system with an attic fan, a contractor confirms the pipe is intact and connected under the slab, then cuts out a section of pipe in the attic and installs an inline radon fan with rubber couplings. The fan is wired to power, a U tube gauge is added to the pipe below, and the exhaust continues out the roof. In York homes, a retest follows after the fan runs.
Why the Attic Works Well
Radon fans must be installed outside the living space, so if any leak occurs on the pressurized side of the fan, it does not push radon into rooms. The attic meets that rule and keeps the fan out of sight.
A passive pipe often already runs straight through the attic to the roof, so there is a ready spot for the fan. The pipe stays inside the house where it is protected from weather, and the fan is shielded from rain and snow.
The attic can be hot in summer and cold in winter, but radon fans are designed for those conditions. The contractor checks that the fan location has enough room to service it later. If anything here is unclear for your home, the written quote is the right time to ask.
Placement and Power
The fan goes on a vertical section of pipe in the attic, ideally where there is space to work and reach it again. The contractor cuts out a length of pipe and connects the fan with rubber couplings clamped tightly at each end.
The fan needs power, so the contractor plans a connection to a nearby circuit. Some attics already have an outlet or junction box. Others need a short new run.
A U tube gauge is mounted on the pipe in the basement or another easy spot, so you can check suction without going into the attic. Above the fan, the existing pipe continues out the roof, keeping the exhaust above the roofline and away from windows. Keeping notes and photos from this stage also helps if you sell the home later.
Checking the Result
When the fan starts, the gauge shows suction right away. The contractor marks the starting level. If suction is weak, it may point to a pipe that is not well connected under the slab, an open sump, or other leaks that need sealing.
After the fan has run at least a full day, place a short-term test in the lowest lived in level under closed-house conditions. Most passive to active conversions bring a clear drop in radon.
Note the date of activation and keep the paperwork. Check the gauge from time to time, listen for changes in fan sound, and retest every couple of years. If the attic fan ever needs replacement, it is easy to reach and swap. Small details like these separate a system that works on paper from one that works in your house.
One Fan, Big Difference
Adding an attic fan to a passive radon pipe is one of the simplest radon fixes. If your York home has a passive system and a high test, call us and we will connect you with a local contractor who can check the pipe, install the fan, and help you plan your retest.
Frequently Asked Questions
Can the fan go in the basement instead of the attic?
No. Radon fans should not be installed in the basement or other living spaces. The attic or the outside of the house are the typical fan locations. The attic is usually best for a passive pipe that already runs through it.
Will an attic fan be noisy in the bedrooms below?
Most radon fans run with a low hum. In the attic, the sound is usually faint in the rooms below. Good mounting with rubber couplings helps. If noise is a concern, ask the contractor about fan models and placement. Ask about it during the visit so the answer is based on your actual home.
Does the attic fan run all the time?
Yes. Radon fans run continuously to keep suction under the slab. Turning it off lets radon return. The energy use is modest, and checking the gauge regularly confirms the fan is working. Keeping your test results and paperwork together makes this easier to sort out.