Radon & HRV Systems

Can someone please explain to me why HRV (Air-Exchangers) should Not be operating during a radon test? Gave a presentation to a group of agents and they all thought this should not affect the test, if anything make it higher if it is operating.
I said the influence of constant air movement, either bringing fresh air in or exhausting old stale air could taint the results. Does anybody have a more definitive explanation?

Were did you get that idea?

From InterNACHI’s Radon course.

1.2.2 Measurement Conditions



Thanks for the info!

An air-to-air heat exchanger is not the same as an air exchanger. Air-to-air heat exchanger is part of the HVAC system. It can be used to heat or cool the home.
An air exchanger, or Heat Recovery Ventilator (HRV), captures the heat from indoor air and exchanges it for fresh outdoor air, thereby introducing fresh air and compromising the Closed-House-Conditions. You don’t want the HRV running for the same reason you want the windows closed.

That is not what the protocol states. (posted earlier)

Air exchange devices that should not be used during a Radon test protocol refers to items such as whole house fans and window fans.

If you have updated protocols that state differently please post the source.

That is what I thought…and yes I was talking about an air-to-air exchanger, HRV. Around here its common/preferred to let them run 24/7, thus this is the reason I was asked why cant we test with it running if its going to be always operational?

If he can’t post the source of his info he is wrong.

I posted the protocol and it clearly says tht internal external air to air exchangers may run during the test but not high volume air changers such as window fans or attic fans or whole house ventilators(very high volume)

You posted the source. The first line in the quote in your post regarding internal-external air exchangers. Please read the quote you posted. I tried to copy and paste it here, but unable.



Perhaps you are not reading the posts above.

Are you considering HRVs high volume?

We all just want to get it right.

Read the line in your quote that is directly before the line you placed in bold. “Internal-external air exchange systems (other than a furnace) … should not be operating during measurements”…
It seems that you’re confusing air changers with heat exchangers.

You omitted some words. Good grief man

With all due respect Mike, I think you’re reading that wrong.

Please explain how a typical HRV is high volume.

With all due respect you are ignoring the term high volume as they define it.

You are also ignoring the last line that clearly states

What do these words mean to you?

It is not unclear to me and we both can’t be right.

Your turn;-)

I’m not ignoring the last line at all. The OP’s question was concerning an air-exchanger, not an air-to-air** heat **exchanger. The source you quoted lists air exchangers along with high volume attic and window fans as devices that should not be operating during the test.
Your turn.

he clearly stated it was an HRV

And the protocol defines what air to air exchangers are.

Your turn again.

HRV are passive systems tied into the duct work. I agree with Larson, how exactly is an hrv high volume? it references fans, there is no fan inside an hrv cabinet.
On top of that, common sense would prevail. If normal everyday living utilized the hrv, the shutting it down IMO would provide a false report.

An HRV introduces fresh outside air into a house. The results of the test will be skewed if it is running.

Hey guys.

In the end we all want to get it right.

I was concerned that the supposed source of the HRV not running was from the NACHI course.

I have not taken the NACHI course and do not know what is actually says.

I took my Radon training at the U of M.

I looked up what I posted and it seems clear to me though it could have been written some what better.

I am not a AARST member but if some one is it would be helpful if they would check out their opinion on this.