Best Practices:
What Every Homeowner Should Know Before Installing an ERV
A properly installed ERV is a game-changer for your home's air quality — but installation details matter. Follow these best practices to protect your investment and get the most out of your system.
Install the ERV in Conditioned Space
For the heat exchange to work, the ducts on the house side must lose virtually no heat. The ERV cannot be installed outside the thermal envelope.
Insulate Both Outdoor Ducts
The outdoor air and exhaust ducts get very cold in winter and will be a condensation risk if left uninsulated.
Use Proper Duct Materials
Rigid duct is best. Flex duct is approved. Dryer vent is not acceptable.
Keep Ducts Straight and Sag-Free
Run straight for at least 24 inches before the first bend. Minimize turns and keep ducts tight and sag-free.
Run All Duct on the Warm Side
In an attic, duct must be under the insulation. In a floor system, duct should run above the insulation.
Go Bigger on Duct Size
Smaller ducts mean higher velocity, more resistance, and lower airflow. Size up for better performance.
Place Intake and Exhaust Terminations Carefully
Keep outdoor intake and exhaust separated. Avoid contamination sources like exhaust vents and garages. Keep intake accessible.
Understand ERV-to-HVAC Duct Connections
Two fans may fight each other when connected to HVAC ducts — and the ERV usually loses. Proceed carefully.
Keep the ERV Accessible
The unit needs commissioning after installation and regular filter changes. Don't box it in.
Commission the System
Measure and adjust airflows after installation. Balanced intake and exhaust is not automatic — it must be dialed in.