The report says some systems had missing or compressed insulation on cold side ducting, lacked grease filters in the kitchen, or did not have a trap in the condensate tube. Other problems included clogged fresh air intakes and dirty HRV cores and filters. It is clear from reading the report that the quality of the installation is often more important than what brand of machine is installed. The report says many of the problems could have been prevented by proper installation. It also recommends the use of flexible ducting be limited.
Good installations cost more money than bad installations.
Flex ducting is cheaper and easier to run than smooth wall pipe. Homeowners contracting their own home should be wary of low price installation costs. Ask if the installer measures air flows and request a final report that shows exhaust and supply flow rates. Look for a certified installer. Select an installer who has had HRAI training.