Why hospitals recover heat
Hospitals run 24/7 with very high fresh-air rates – operating theatres, isolation rooms, and wards all demand conditioned outdoor air. Ventilation can be 30-50% of a hospital’s energy bill. Air-to-air recovery cuts that load sharply, but infection control sets a hard rule: supply and exhaust must never mix.
The safe choice: plate exchangers
Because cross-contamination is unacceptable, fixed-plate air-to-air heat exchangers are the standard. They keep streams physically separated while transferring sensible heat. Rotary wheels are used only where a small carryover is acceptable and a purge sector is specified.
What you recover
- Heating-season sensible heat from warm exhaust.
- In humid climates, enthalpic cores also recover latent load.
- Pressure drop must stay low – fans run constantly, so every Pascal costs money.
Integration and payback
Recovery is best designed into the AHU, but a retrofit unit can be added to existing exhaust risers. Most hospital projects pay back in 3-5 years. Size to winter design and verify with our pressure-drop guidance to protect fan energy.
Infection control sets the boundary
Hospital ventilation is governed by the need to protect patients, so any recovery device must respect pressure relationships between rooms and keep exhaust and supply isolated. Fixed-plate exchangers satisfy this because the streams never contact. Where a rotary wheel is used, the purge sector and leak-class specification must be documented as part of the infection-control risk assessment.
Pressure drop and continuous operation
Hospital air handling units run around the clock, so the fan energy tied to recovery pressure drop is paid every hour of every day. Selecting a core with a low, stable pressure drop, and confirming filter loading does not push the fan beyond its head, protects both energy cost and the reliable airflow that clinical spaces require. A small Pascal saved here is worth more than in an intermittent office system.
Validation and monitoring
After commissioning, trend supply and exhaust temperatures and the pressure drop to confirm the designed effectiveness is maintained. Any drift may indicate fouling, seal wear, or bypass leakage, and in a hospital that also means re-checking that isolation is intact. Size to the winter design condition and revisit the pressure-drop guidance to keep fan energy in check.
Frequently Asked Questions
Can hospitals use rotary wheels?
Only where a small carryover is acceptable and a purge sector is specified. A plate exchanger is the safe standard for infection control.
Why are plate exchangers preferred in hospitals?
They keep supply and exhaust physically separated, satisfying the no-mixing rule that infection control requires.
How does recovery affect hospital energy bills?
Ventilation can be 30 to 50 percent of a hospital energy bill. Recovery cuts that load, and because fans run 24/7, pressure drop control matters.
What payback do hospital projects see?
Most pay back in 3 to 5 years. Size to the winter design condition and verify pressure drop to protect fan energy.