Clean Air Council's Salesforce instance is based on the Nonprofit Success Pack (NPSP), put out by Salesforce.org. See that link for official documentation on NPSP features. Except where necessary to explain customization within CAC, this wiki will not document standard NPSP functionality.
Until end of February 2021, Clean Air Council was using the legacy 1:1 Account Model of NPSP. The conversion to the Household Account model is now complete but there could be some legacy fields or setup floating around. (And as of 3/16/2021 the legacy accounts have been deleted but not the households.)