Author Topic: Radon removal via HRV  (Read 232 times)

Offline Lee Batchelor

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Radon removal via HRV
« on: December 19, 2018, 03:11:20 PM »
    Hi everyone! I'm new here. I built a house in 1982. It has the following details:
    • 2,000 sq ft ranch style
    • Double stud walls - outside perimeter structure 2x6 fully insulated and air barrier sealed. Inner 2x4 wall offset to the exterior wall insulated (no air barrier), which carries electrical and other minor stuff
    • Floor trusses - full web trusses, 34 foot span
    • Floor truss pockets recently spray foamed
    • Attic R60 insulation

    I heat the house with a gas furnace. As you can see I need an HRV. I installed a Venmar EV05-500. It works very well. Problem: I have a radon level of 200 to 300 Bq/m3. The HRV can drop that level down to below 100 Bq/m3, but the house humidity drops below 40 percent, which is really rough on the skin and nostrils!

    Questions:
    • There doesn't seem to be a reliable agreement about what's considered a safe level of radon. The WHO says less than 100 Bq/m3, whereas the Canadian government says less that 200 Bq/m3. I believe the U.S. folks say less than 148 Bq/m3. Who the heck do we believe??
    • What is my best way to keep these levels down without drying my house out like a leaf? I've heard about these suction fans you can install under your cement slab. They create negative pressure, which sucks the radon out.
    • Can my HRV be used in another way to exhaust the radon? At the moment, the freshened air is fed into the cold air return in the basement. Can I put an additional pipe in that runs outside so I can choose whether or not to keep the freshened air or get rid of it? I draw stale air strictly from the basement at the moment.

    Many thanks!

    - Lee


Offline Admin

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Re: Radon removal via HRV
« Reply #1 on: December 20, 2018, 01:02:24 PM »
I don't much about Radon gas or its dangers.  In new construction they dig below the foundation and use a fan system to suck out the Radon gas before it enters the home.

You should hire a Radon mitigation specialist to give you options.

Are far as HVAC equipment goes, the HEPA systems or UV bulbs don't stop Radon gas.  Using the HRV is really the only option I know of.  When you balance the HRV try to create a positive pressure inside the home and seal any cracks on the foundation floor.  This may help prevent Radon gas from entering.


Offline Lee Batchelor

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Re: Radon removal via HRV
« Reply #2 on: December 20, 2018, 03:34:26 PM »
Thanks :)! I wondered about the cracks too. Unfortunately, roughly one half of the area is carpeted and would need to be pulled up to access the floor cracks. I'm pretty good with my hands, so the thoughts of installing a sub-slab suction fan to outdoor air, doesn't frighten me in the least. I'll check to see if there any radon specialists in my area first. Thanks again!

- Lee

Offline bster352

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Re: Radon removal via HRV
« Reply #3 on: December 27, 2018, 09:56:22 AM »
Not sure where you are but check these guys out... https://www.mr-radon.ca/ .