An air handling unit (AHU) conditions outdoor air before it enters a building. Without recovery, that outdoor air must be heated or cooled from scratch every hour. Adding a heat recovery core to the AHU is the single highest-impact energy measure for ventilation systems.
Where the Exchanger Sits in an AHU
The recovery core is placed in the exhaust-to-supply air path, usually after the filters and before the supply fan. In modular AHUs, it drops into a dedicated section sized for the core dimensions.
Matching Exchanger Type to AHU Duty
| AHU duty | Recommended core |
|---|---|
| General office fresh air | Counter-flow plate or enthalpy wheel |
| Laboratory / hospital (clean) | Plate (no carryover) |
| High humidity climate | Enthalpy rotary wheel |
| Retrofit, limited space | Heat pipe or run-around coil |
Integration Tips
- Keep face velocity in the 2–3 m/s range for balanced efficiency and pressure drop.
- Add bypass dampers for free cooling in mild weather.
- Use EC fans to capture part-load savings.
- Specify easy-access doors for core cleaning.
See our modular AHU solutions for recovery-ready configurations.
Factory assembly and casing quality matter as much as the core itself. Specify a casing leakage class per EN 1886 so recovered air is not lost to the mechanical room, and confirm the core section has tool-free access doors for service. Place the filter stages ahead of the recovery core to protect it, and keep the supply fan after the core to avoid pressurizing the exhaust side. For clean applications, verify that face velocity and core bypass meet the required air-change rates. Commission the unit with the building management system so the bypass opens on cool days and the recovery core carries the heating or cooling load the rest of the year. Explore modular AHU solutions with recovery-ready sections in standard sizes.
Frequently Asked Questions
Can I retrofit an existing AHU?
Yes, if there is physical space and a matching exhaust duct. Heat pipes and run-around coils are the most retrofit-friendly.
Does recovery hurt IAQ?
No. Plate and heat-pipe cores keep streams separate; only enthalpy wheels transfer a little moisture, which is managed by purge sectors.