HRV with bathroom exhaust fan
I asked this question in the comments of an article, but thought I would have more luck here…
I am installing a LifeBreath 155ECM HRV in a new home. It will be exhausting air from 3 bathrooms spread across 2 stories. The HVAC sub is recommending installing separate bathroom exhaust fans for local exhaust (shower moisture, odor, etc.).
An energy star consultant says this is not necessary and redundant. It certainly seems redundant to me, but the HVAC sub feels that at max speed on the Lifebreath you are pulling around 150cfm @ .2″ static pressure that means 50cfm at each bathroom location. For 2 of the 3 bathrooms, I would typically use a 110cfm PAnasonic Whisper Green fan because of the size of the room. So the HVAC sub feels like it will take too long running the HRV at full speed to adequately vent the space.
A 50cfm Panasonic has a rating of 8.5cfm/watt while the Lifebreath is 1.5 cfm/watt. So it seems that the Panasonic is much more efficient.
Any thoughts…additional bath fan or just wire the HRV to be switched to high speed for local exhaust?