Zehnder Interview Series: Why Is Commissioning an HRV System So Important?


Interviewer:  Could you please introduce yourself, Matt?     

Matt Groves:  My name is Matt Groves and I’m the Northwest Technical Sales Engineer for Zehnder America. My territory covers Washington, Oregon, Idaho, Montana, and Western Canada along with Alaska.  I also live in a very energy-efficient house with a Zehnder CA350 inside providing the fresh ventilation so I’m familiar with the system both as a Zehnder engineer and a homeowner.

Interviewer:  Why is it important to have an HRV system commissioned?

Matt Groves:  Commissioning an HRV system is a critical step to ensure that the system is installed correctly for optimal performance. Commissioning ensures that the correct air supply and exhaust air flow rate meet the design requirement and also makes sure the HRV system is operating at its most efficient setting.

Interviewer:  What should one do to prepare the system prior to the commissioning?

Matt Groves:  We have a great online commissioning request form that works as a convenient checklist to make sure a system is ready for commissioning.  I recommend first going to the Zehnder website and review the checklist on it to verify that you’re ready. The checklist includes items such as having all the unit and controller fully installed and operating.

Interviewer: Who does the commissioning?

Matt Groves:  We have third-party commissioning agents, who go out and perform the commissioning.  In areas where third-party commissioning agents aren’t available, someone on Zehnder’s technical team conducts the commissioning process.

Interviewer: What is checked during the commissioning process?

Matt Groves: Whether it’s a third-party commissioning agent or a Zehnder technical representative, we ensure the system is operating properly and the correct flow rates are going to each room.  We also check the exterior intake and exhaust grills. We verify the system looks like it’s installed per our design that we would have made for that system. We measure the flow rates in each room and then balance as needed to make sure that each room is getting the designed airflow or the airflow that meets the new requirements or codes for the building.

Interviewer: Why is a Zehnder system easier to commission compared to other systems?

Matt Groves: Other manufacturer’s systems often use dampers to adjust the flow rate in ducts which can create noise and are generally harder to balance.  Where in our HRV system, you have the capability of adjusting the individual exhaust side and supply side fan motors independently in 1% increments to achieve a balanced total flow.  So if there’s more resistance to the intake you can adjust for that with motor speeds instead of adding a damper.  Then the air goes through one of our Comfowell (silencer box) with a manifold on the end which then splits it off into many smaller Comfotubes (air distribution tubing).  This Comfowell (silencer box) splits the flow into approximately equal amounts to most of the tubes. It depends on the length and how many curves are in the tubes but generally it gets each room close and then we just have to fine tune the adjustable register in each room.

Interviewer: How does someone schedule the commissioning of a new system?

Matt Groves: It’s very easy to schedule.   Again, you just go onto the website and complete the required checklist and project information. The simple checklist ensures the system is ready for commissioning.  Once we receive it, we’ll review it and schedule somebody to come out and perform the commissioning.

Interviewer: Do you have any additional advice on commissioning?

Matt Groves: My main point would be that commissioning is a very vital step to ensure proper operation of the equipment and should not be overlooked.  So for us, it’s critical to ensure the systems in the field are operating properly.

Interviewer:  Thanks Matt, I appreciate your time to explain the importance of commissioning an HRV system.  

Matt Groves: You’re welcome, have a great day.