In the Fresh-r, heat recovery runs via the copper, which conducts heat 1000x better than plastic, resulting in a thermal yield of 87% by 80 m³ per hour.
The Fresh-r ventilation is balanced. This means that the same amount of air is blown into your residence as is blown out. These air flows do not touch each other. But they do go through the same heat exchanger. That heat exchanger contains a mat of fine woven copper wire. If the air is warmer than the copper wire, then the heat from that air flows through the copper. If the air is colder than the copper wire, then the heat flows from the copper to the air. If it’s 20° inside and 0° outside, then the air blown into the interior is 18°. And this efficiency does not decrease as the heat exchanger gets older because the copper wire is coated.