As long as active minds & hands are involved with DIY HRV/ERV, I thought it would be a good idea to post some links regarding HVAC industry approved levels of room air replacement. They boil it down to Air Changes per Hour (AKA:
ACH). This takes into consideration the Cubic Feet Per Minute, and also the volume of the room.
Here's a
link to a page that clearly explains how to do the claculation.
And here is a link to a PDF that has the industry-approved air change rates, and also the formulas used to calculate the air change rate.
(* download & save *).
Interesting to note that the Passive House standard is different and lower, and has a per-person standard or a per-area standard.
Early Passive Houses were able to hit the stringent heat-retention targets that were saught, but people complained that the Passive Houses were "stuffy". After rentless Germanic testing the following ventilating level was determined:
- Passive House per-person = 15 CFM per person.
- Passive House per-area = 15 CFM per 377 square feet floor area.
This works out to 0.3 ACH for a house. This works out to 1/20 to 1/67 of the recommended ASHRE standards. Interesting, huh?
I know that the Americans pretty much invented the science of air conditioning and ventilating, but the Germans should not be lightly dismissed.
Anyway I read an interview with one of the most prominent European Passive House spokesmen, and the question was raised as to whether or not a HRV would really pay for itself, and he essentially said that you should
begin your design with Heat Recovery Ventilating.
I'm sold.
-AC_Hacker