My first post here.
I'm an owner builder now spec'ing the mechanicals on a 2300 s.f. wood frame house with EIFS in a mixed humid heating climate. Heat calc calls for 52,000 BTU of cooling and 66,000 of heating, and the shell of the house should end up extremely tight.
Crawlspace will be sealed and insulated with foam around perimeter and poly under the slab.
Projected HVAC setup to include a single high velocity air handler for the AC and, in a separate system, a single ERV with hydronic heat coil for the ventilation, supplemented by a gas fireplace. These systems are merely hypothetical, have not been designed and integrated yet.
Question: I understand that I need another separate mechanical ventilation system for the crawlspace, which should draw some of the dirty air out of the living space while mopping up soil gases that seep into the crawlspace.
Option A is a single pipe with inline fan venting to the rooftop (Building Science's recommendation)
Option B is a squirrel cage blower with several inlet hoses stationed at the corners of the crawlspace (my local GC does this)
Option C is to put air return(s) for the ERV ventilator down in there and use the crawlspace as an exhaust plenum for the ventilation system (I read about this somewhere)
Any opinions about these options or other suggestions about how to integrate crawlspace ventilation into the overall system requirements? The basic mission is cost effectiveness and efficiency with high emphasis on IAQ.
I realize I should be talking to an engineer, but I haven't hired one yet.