Ron the principle is the same with IAQ. Higher levels when HRV’s are off. Thanks for doing this.
Was this a tight house design?
What amount of outside air was provided with the HRV?
House was built in 2005, A fairly tight house by today’s standards. Not sure what your asking about HRV air intake, but brought fresh air into the home with a 6" pipe.
A 6" can bring up to 225 cfm at .2 inches w.g of air from outside. This is why I would need to have the info as to how much was being provided from outside that did change the readings. On low may be OK.
Since it is fairly tight house I would say this is a good example of how effective a HRV can be in reducing levels.
I understood a HRV (heat recovery ventilator) up north is the same as a ERV (energy recovery ventilator) in the south. I know hundreds of homes in SW Florida have ERV’s for radon mitigation.
radonfix.com is the best radon mitigation business in Florida.
sub slab systems don’t seem to work well here. Gene has done 10’s of thousands of radon mitigations.
http://radonfix.com/index1.htm
The use of an ERV is required when mitigation radon in large (over 2,000 Sq.Ft.) condominiums because the amount of outside air required to reduce the radon level is typically to much of an additional load on the homes AC system resulting in high humidity and the potential for mold problems. ERV systems can be difficult to install and require cosmetic alterations such as drywall enclosures and soffits. ERV units can also be installed in single family homes with moderate radon levels when ASD is not applicable. The benefit of an ERV system goes beyond the ability to reduce radon levels but often times will improve the overall indoor air quality.
http://www.nachi.org/documents/radon-test-in-progress.pdf **???
**
3. The EPA recommends that short-term radon testing which lasts for no longer than a week be
conducted under closed-building conditions. Closed-building conditions require: 1) keeping all
windows closed;; 2) keeping exterior doors closed (except for normal entry and exit);; and 3) not
operating fans or other machines that bring in air from the outside. Note that fans that are part of
a radon reduction system, or small exhaust fans operating for only short periods of time, may run
*normally during the test.
*When doing short-term testing lasting less than four days, it is important to maintain closed-
building conditions for at least 12 hours prior to beginning the test, as well as for the entire testing
period. Do not operate fans or other machines that bring in air from the outside.
Thanks for posting it .
It is worded even less clear than the nationally recognized protocols.
Some HRVs run continuously while others only run when when high humidity areas are occupied.
Use your judgement and document the conditions present.
IMHO