Cold climates (heating-dominated)
Long, sub-zero winters make frost the enemy. Rotary wheels need purge sectors and occasional defrost; plate exchangers need bypass or preheat. Frost protection strategies are mandatory. Sensible-only recovery is usually enough because winter air is dry.
Temperate climates
Mild seasons with both heating and cooling loads favor balanced, all-season recovery. Plate and rotary both work; choose on footprint and first cost. Enthalpic cores add value where summer humidity is notable.
Hot-humid climates (cooling-dominated)
Here the goal is to keep moisture out while rejecting heat. Enthalpic (total) recovery – membrane or desiccant – recovers both temperature and humidity, lowering cooling coil load. A sensible-only plate unit still helps but ignores the latent load that drives most of the cooling energy.
A quick decision rule
- Need strict stream separation? – Plate.
- Maximize effectiveness at huge airflow? – Rotary wheel.
- Ducts far apart? – Run-around coil.
- Humid climate + tight moisture control? – Enthalpic/desiccant.
For a side-by-side comparison, see plate vs rotary vs heat pipe. Always size to the design (not average) condition and verify with a payback calculation.
Design condition, not average
Recovery effectiveness is only as good as the condition it was sized for. Sizing to the average climate undersizes the device for the worst month, when energy and comfort pressure are highest. Always select against the heating and cooling design days for the site, then confirm the unit still performs acceptably at part load.
Enthalpy versus temperature thinking
In humid climates the latent load often dominates cooling energy, so comparing devices on temperature alone misleads. An enthalpic core that recovers moisture can cut more cooling energy than a higher-effectiveness sensible plate, because it lowers the work the cooling coil must do. Read the local psychrometrics, not just the temperature swing.
Control and bypass
Climate also dictates control: cold-climate units need defrost or preheat logic, while cooling-dominated sites benefit from a summer bypass that stops the core from reheating incoming air. Build the control sequence into the specification so the device helps in both seasons rather than fighting one of them.
Frequently Asked Questions
Which exchanger suits a cold climate?
A plate unit with bypass or preheat, or a rotary wheel with purge and defrost. Frost protection is mandatory, and sensible-only recovery is usually enough because winter air is dry.
What about hot and humid climates?
An enthalpic core, membrane or desiccant, recovers both temperature and humidity and cuts the latent cooling load. A sensible-only plate ignores that latent load.
Should I size to the average or the design climate?
Always size to the design, worst-case condition, then confirm the unit still performs at part load.
How do I choose between plate, rotary, and heat pipe?
Plate for strict separation, rotary for maximum effectiveness at huge airflow, heat pipe for passive no-cross-contamination duty. See the comparison guide for detail.