HRV – New Construction – how to provide bath exhaust and meet the 2021 codes? – GreenBuildingAdvisor

Hi Folks,

I’m planning to build a 2000 sqft, 3 bed, 2.5 bath ranch home,  Zone 6, central Maine. I will be following all 2021 IRC and IECC codes including the ventilation requirements, and they are enforced by the municipality.  I expect to achieve the 3ACH blower door requirement. 

I am planning to install an HRV.  I would like the HRV to also provide the exhaust ventilation in my baths, and negate dedicated bath fans. I’m looking at the LifeBreath 195 DCS, damper defrost (not recirculating). 193 CFM. 

I’m reading the 2021 codes and commentary’s (Chapter 15 IRC & Chapter 4 IECC) on ventilation and my head is spinning.   

I’m looking for some guidance – What are people in the field experiencing?  

– Can I install an HRV system myself? 

– How do I prove that my HRV will provide the required 50CFM exhaust at my baths? 

–  Are any of your Enforcement Officers requiring a 3rd party hood flow test?

– Do I need a engineered (stamped) system? 

– Do I need to hire an HVAC guy to install this??

For the record, I’m a carpenter, not an HVAC tech – laymen’s terms please 🙂 

 In my current house that I built in 1995, I installed (DIY) a LifeBreath 150MAX HRV that has provided sufficient bath ventilation for 30 years. Controls in each bath with 20-40-60 minute time to run on high. I ‘designed’ the ductwork to mimic what I’d seen in the field, which seemed like common sense – exhaust in baths, laundry, and kitchen area, supply beds and living areas, use short duct runs as possible.  (The kitchen has it’s own dedicated stove exhaust fan also) I balanced the system with a borrowed analog manometer and haven’t touched it since, with no issues.

I’d like to do this again….

Thank you!

Mark