Usually, Yes
Most central air-handling units can be retrofitted. A plate core often slots into the AHU section with minimal ductwork changes; a rotary wheel needs space for the wheel and its drive.
What to Check First
- Physical space in or beside the AHU
- Balanced supply and exhaust airflow
- Available fan capacity for the extra pressure drop
- Controls to manage frost protection if needed
Retrofit Tips
Start with a crossflow plate core for simplicity. Verify the fan can handle the added static pressure before committing, and model the savings at your actual operating hours.
Payback
Retrofits in continuously ventilated buildings often pay back within a few seasons because the duty runs year round.
Background
Questions about Can I Add Heat Recovery to an Existing System? usually come from engineers and facility managers weighing the cost of wasted energy against the price of recovery equipment. Heat that leaves a building or process as warm exhaust is not lost forever if it can be captured at the source. Understanding where that energy goes is the first step to controlling it.
Why It Matters for Heat Recovery
Make-up air must be heated or cooled to comfort or process setpoints, and doing that from scratch is expensive. By preconditioning the incoming air with heat taken from the exhaust, a plant can cut heating and cooling loads by half or more. The effect compounds in cold climates and in continuous processes that run around the clock.
Practical Takeaway
Start by measuring airflow and temperature on both streams, then calculate the available energy and the realistic recovery rate. Compare that saving with equipment and installation cost to get a payback period. If the payback is acceptable, specify a core sized for the duty and arrange filtration and drainage so the unit keeps performing.
Frequently Asked Questions
Where do I start? Measure the two airstreams and the temperature difference, then size from those numbers. What saving is realistic? Most systems recover 50 to 80 percent of the sensible heat in the exhaust.
Practical Selection Checklist
For the Can I Add Heat Recovery to an Existing System? duty, confirm the measured airflow and the temperature difference between the two airstreams before specifying any unit. Choose the core type that matches the exhaust cleanliness and the recovery target, allow margin for fouling, and verify the pressure drop stays inside the fan curve. Place filtration ahead of the core and provide a condensate drain where the supply side may fall below the dew point.
When to Specify This Solution
Energy recovery suits any plant or building that expels warm exhaust continuously while drawing in fresh air that must be conditioned from ambient. Common candidates include make-up air units, drying rooms, commercial kitchens, paint booths, and general process ventilation. Where the annual cost of heating or cooling make-up air is material, a correctly sized exchanger usually pays back within one to three operating seasons.
Next Steps
Start by logging the supply and exhaust conditions for a full duty cycle, then size the core from those numbers rather than from nameplate estimates. Compare the projected energy saving with the equipment and installation cost to get a payback figure, and review the comparison and product guides for the specific configuration that fits your site.