Get Full Government Meeting Transcripts, Videos, & Alerts Forever!
Get email alerts on the Ventilation Conditioned Space topic
No spam. Unsubscribe anytime.
Committee tables opinion on whether ERVs/HRVs must be inside conditioned space
Summary
The Mechanical Ventilation, Plumbing & Energy Codes Committee tabled an interpretation request from the City of West Richland about whether energy- and heat-recovery ventilators must be installed within conditioned space under sections R403.3.2 and R406 of the Washington State Energy Code.
The Mechanical Ventilation, Plumbing & Energy Codes Committee of the Building Code Council on May 12 tabled an opinion request from the City of West Richland asking whether energy recovery ventilators (ERVs) and heat recovery ventilators (HRVs) must be installed within conditioned space to qualify for the R406 credit.
Committee members and industry commenters debated whether the credit—written to reward heating and cooling distribution entirely inside the thermal envelope—was intended to include standalone ventilation equipment. "HRV, ERV is gonna make up such a very small percentage of the overall heating and cooling equipment," said Damon Doyle, of Doyle Construction, who warned that requiring every intake and exhaust duct to be within conditioned space could disincentivize installation of ERVs and HRVs. Rob Marks of Snohomish PUD said units need to be accessible for service and that attic placement can impede maintenance.
Members noted code citations in the staff draft opinion, including R403.3.2 (ductwork in conditioned space) and R406 (the credit language). Committee members observed that R403 language focuses on supply-and-return looped systems and that intake and exhaust ducts for ventilation devices are different in function. Past practice and modeling assumptions mattered to members: staff recalled that modeling for the credit established thresholds (about 300 kWh/year of savings as a rough cutoff for awarding the half credit) and that the credit was intended to reward HVAC distribution, not necessarily ventilation-only equipment.
Committee discussion surfaced implementation details and exceptions cited in meetings and code training: a long-standing allowance of up to 10 feet of return and 5 feet of supply outside conditioned space; the historical example of inexpensive ceiling-mounted ventilation units; and the practical reality that many ERV/HRV units are installed in attics or other unconditioned spaces. Darren and others noted many commercially available ERV/HRV units are designed for attic installation, and that forcing all units into conditioned space could undermine their function.
After discussion, members agreed they needed more information from the Energy Code TAG and additional analysis of the modeling assumptions used when the R406 credit was developed. The committee voted to table the opinion request and bring it back to the council with more background work and stakeholder input. Todd Bayreuther moved to table the opinion; the motion carried.
The committee identified next steps: gather modeling assumptions used for the credit, ask the Energy Code TAG and equipment subject-matter experts whether intake/exhaust ducts should be treated differently than supply/return ducts, and present findings at the full council meeting later in the week.
