American vs: Canadian Radon Mitigation Systems

What’s the difference?

Simply put, the Canadian type radon system has the radon fan mounted inside the basement with the vent pipe venting through the wall near the ground similar to a dryer vent. The American type system typically has the fan mounted on the exterior wall near ground level and the vent pipe runs up the side of the house past the roof. In all most every other way the two types of systems are the same.

Indoor radon fans are better in several ways.

Why is the Canadian Type Radon System Better?

In Canada they used to install systems following the American Standards in which most cases the radon fans were mounted on the exterior of the homes. The cold weather in Canada would sometimes cause the condensation produced in the vent pipe above the radon fan to freeze over and block the air flow which halted the radon mitigation until temperatures warmed up, days or weeks later and the ice melted. The freeze thaw process also greatly reduced the life of the fan. Some smart people in Canada got together and came up with a better idea.

Indoor vs Outdoor Radon Fan Benefits:

  • Indoor fans are Safer, because they will not freeze up and stop working when it gets really cold.
  • Indoor radon fans last about 3 to 4 times as long. Replacing a radon fan typically costs $250 to $500.
  • Mitigation systems with indoor radon fans are more efficient. They need less pipe, which equals less air flow resistance, which means less energy used.
  • Indoor radon fans are less expensive to operate, saving money on your electric bill.
  • Indoor radon fan systems cost less to install. Typical savings of $100 to $300 or more.
  • Canadian type radon mitigation systems are much more aesthetically pleasing. No fan mounted on the wall and pipe running up the exterior to above the roof .

Why the Controversy?

For the most part the old and current American EPA and National Radon Mitigation Standards of Practice do not allow radon fans to be placed inside basements, below or in the living areas of the home for supposed safety reasons. In contrast Health Canada, their agency similar to the EPA, recommends that radon fans should be preferably placed in basements, below or in the living areas of the home for reasons described above.

New York State Radon Mitigation Systems

In New York as of this writing, 12/29/2021 there is no state regulatory oversite regarding radon mitigation so homeowners can install any type of radon mitigation system they like, as long as it complies with applicable local building codes, such as wiring. Most localities have no building code requirements for radon mitigation.

Brief History – The Cowboy Days of Radon Mitigation

Canada actually followed the original American Radon Mitigation Standards, set by the EPA back in 1993. At the time, in the early days of radon mitigation, the EPA scrambled to put together some type of standards for mitigation of radon since contractors and homeowners were throwing together all type of things to mitigate radon. They used all types of unsuitable fans and and vent materials from paper thin, flexible plastic dryer vent. Many of these cobbed together components fell apart in no time and became safety hazards. The EPA basically copied the Plumbing vent code for venting sewer gas and today, in 2022 the American National Standards of Practice for Radon Mitigation have changed very little.

Canada Health publication “Reducing Radon Levels in Existing Homes: A Canadian Guide for Professional Contractors” An excerpt from Section 9.3 – Fan Location

“In the early days of radon mitigation, prior to development of the US mitigation Standards, the fans used were not airtight, and leaked some of the exhaust air from their casings. A variety of ducting materials was also used and not all joints were airtight. As a result, best practice was to place the fan and discharge piping outside the building envelope. The interior piping was then under negative pressure, so neither fan nor duct leakage would enter the building. Fans located outside the building envelope are required by US mitigation standards.

In-line centrifugal fans specifically designed for radon mitigation are now available. Some airtight fan designs are available with sealed joints; some have the casing joints and electrical connections located on the suction side of the fan, so leakage from the fan is not a concern. Plastic plumbing pipe is now used routinely for the suction and exhaust ducting, with airtight solvent welded joints in the piping and airtight rubber plumbing couplers to the fan.

As properly installed fans and ducting will not leak soil air and radon into the building, the fan no longer needs to be located outside the building envelope, but can be mounted inside the building. If this is combined with a grade level discharge, almost the entire system can be inside the thermal envelope. In cold climates, this eliminates concerns about condensation or frost in the fan or piping, as only a short length of discharge pipe outside the house will be exposed to colder temperatures.

A fan should be installed so that the flow is vertical, so that any condensation in the system will drain through the fan, rather than pooling in the casing. To reduce vibration and noise transfer to the building, it should be connected to the piping with airtight rubber plumbing couplers that hold the fan 1 cm from the pipe. If the supply and discharge pipes are firmly mounted, the fan can simply be attached to the pipes by the couplers without other support. If it is attached to a wall, a masonry or concrete wall will give lower noise than an internal framed wall.

If the selected fan is not airtight, it must be mounted outside the building envelope. In cold areas, an outside fan is at risk from premature failure due to moisture in the exhaust air condensing, and freezing in the fan. To prevent this, a fan mounted on the exterior of a building should be placed inside an enclosure (commercially available enclosures are available) for cold weather protection. A condensation by-pass should be installed to collect and divert condensation in the discharge pipe around the fan. To prevent the condensate from freezing, the discharge should be led to the soil through an insulated pipe, or in very cold areas, back into the fan suction pipe. The suction pipe inside the house must be sloped so that condensate passing through the fan can drain back to the sub-slab fill with no low spots where condensate can accumulate.”

Source Location: Canadian Radon Mitigators Installation Guide.pdf (