Within plate heat exchangers, the arrangement of the two airstreams decides how much heat you recover. The two standard layouts are crossflow (streams cross at roughly 90 degrees) and counterflow (streams run in opposite directions, one entering where the other leaves).
Why counterflow wins on effectiveness
Heat transfer is driven by the temperature difference between the streams. In counterflow the cold supply air meets the coldest exhaust at the exit and the warmest supply meets the warmest exhaust at the inlet, keeping a large temperature difference across the whole plate. Effectiveness commonly reaches 80% to 90%.
In crossflow the streams are perpendicular, so part of the plate always works across a smaller temperature difference. Typical effectiveness is 60% to 70% for the same face area.
| Factor | Crossflow | Counterflow |
|---|---|---|
| Effectiveness | 60% to 70% | 80% to 90% |
| Packaging | Compact, easy to stack | Needs offset inlets/outlets |
| Frost behaviour | Simpler to bypass | Exhaust exit runs coldest |
| Cost at equal recovery | Lower core cost | Higher core cost |
When crossflow is the right call
- Tight spaces: crossflow cores package easily in compact air handlers and rooftop units.
- Moderate targets: if 65% meets the energy code, crossflow saves core cost and fan power.
- Retrofit: the square footprint often drops into existing ductwork more easily.
When to pay for counterflow
Cold climates and aggressive savings goals justify counterflow. At a 20 degree Celsius difference, moving from 65% to 85% effectiveness recovers roughly 57% more energy from the same airflow, often paying back the extra core within a heating season.
For the broader type decision see our plate vs rotary guide and the efficiency deep-dive.
Specifying a unit for your project?
EN159 builds plate, rotary, heat-pipe and counterflow air-to-air exchangers. Send airflow (m3/h), inlet temperatures and available space and we will size it.
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