Home / Services / Commercial HVAC / Veterinary Clinics & Animal Hospitals
Commercial · Veterinary Clinics & Animal HospitalsVeterinary Clinic & Animal Hospital HVAC
Veterinary clinic and animal hospital HVAC is a pressure and zoning job: the isolation ward is kept negative and exhausted outdoors, the surgery is kept positive, and air from kennels and wards is never recirculated into reception or exam rooms. Ontario clinics are accredited against the College of Veterinarians of Ontario facility standards, which call for adequate ventilation free of offensive odours, humidity and temperature control, and isolation ventilation that minimizes cross-contamination from room to room. A clinic running every room off one rooftop unit with a shared return cannot hold those pressure relationships, and that is the usual starting point for our work.
The accreditation standards approved by the College's Council in December 2023 are written as outcomes, and they leave the method to the facility. For an isolation room, the College's guidelines give examples: a negative-pressure arrangement where air flows into the room and is exhausted outside, away from animal areas; HEPA filtration on the air leaving the room; or an in-room HEPA unit. Hospital enclosure areas must have adequate ventilation, lighting and temperature control, with ventilation removing odour, dampness and gases such as ammonia. We build to those outcomes and give the facility director the airflow readings for the inspection file; the College decides whether the clinic passes, not us.
Pressure is created by an imbalance on purpose. An isolation ward gets its own exhaust fan ducted to the roof and slightly less supply than exhaust, so air leaks in under the door and none leaks out. A surgical suite gets the reverse: more filtered supply than return, a door that closes, and no return grille shared with a ward. Kennel and ward air leaves through exhaust instead of the return duct, which is why these rooms cost more to heat and cool than their floor area suggests, and why a plate-type heat recovery ventilator, which keeps the two air streams apart, is worth pricing on the general ward exhaust.
Animal hair and dander change the maintenance schedule. Return grilles in treatment and grooming areas mat over, filters load in weeks, and a clogged filter cuts airflow, which erases the pressure difference the rooms depend on. Wards need more air changes than an office to keep ammonia and odour down, so we check delivered airflow against the design instead of assuming it. Surgery adds waste anaesthetic gas: the College requires a scavenging system wherever inhalant anaesthetic is used, and an active system needs a dedicated exhaust route to the outdoors, which we install and maintain while the scavenging equipment itself is verified by an independent third-party technician.
Many clinics operate from plaza units or converted houses, not purpose-built hospitals, so the work is usually a retrofit above a finished ceiling while appointments continue. We stage it room by room, make the isolation and surgery changes on a day those rooms are not booked, and keep the reception system running throughout. Boarding and daycare operations have a different, higher-volume odour problem covered under dog daycare and kennel HVAC, and human-health practices are under medical and dental clinic HVAC. Start with commercial HVAC for how we run projects, or send us your floor plan and the rooms that worry you.
Equipment we install and service
A dedicated fan ducted outdoors and discharged away from air intakes and animal areas, with supply trimmed so the room stays negative. A simple pressure indicator at the door frame lets staff confirm the direction of airflow at a glance.
Filtered supply air in excess of return so the suite stays positive to the corridor, with temperature and humidity held steady for patients under anaesthetic. The waste-gas exhaust route for an active scavenging system terminates outdoors.
General exhaust that removes kennel air from the building instead of returning it to the rooftop unit, paired with tempered outdoor air to replace it. Dental stations may get a local extraction fan, which the College's guidelines suggest for aerosols from scalers and handpieces.
The packaged units or split systems serving reception, exam rooms and offices, fitted with the highest-efficiency filter the fan can handle. Hair-loaded filters and matted return grilles are the most common service finding.
What goes wrong in these buildings
- Clients can smell the kennels from the waiting room.
- Our accreditation inspection is coming up and I cannot show how the isolation room is ventilated.
- The surgery is the hottest room in the building once the lights and the warming units are on.
- We change filters and a month later they are grey with hair again.
- Staff get headaches in recovery and I do not know where the anaesthetic exhaust actually goes.
- The whole clinic is on one thermostat in reception.
How it works
We mark every supply, return and exhaust on your floor plan and test which way air moves under each door with a smoke pencil and a manometer. You see which rooms share air today.
Isolation gets dedicated exhaust, surgery gets surplus filtered supply, and ward air is taken off the common return. Changes are made above the ceiling in stages so the clinic keeps seeing patients.
Final airflow and pressure readings, filter specifications and a maintenance interval go into a short report. It is written for your accreditation file and for whoever services the system next.
Common questions
Does the College of Veterinarians of Ontario require negative pressure in isolation?
The standard requires a ventilation system that minimizes the risk of cross-contamination from room to room. Negative pressure with exhaust to the outdoors is one example the College gives of meeting it; HEPA filtration of the air leaving the room is another. Read the current Accreditation Standards for Veterinary Facilities in Ontario and confirm with the College, since its inspector makes the call.
Can you inspect or certify our anaesthetic gas scavenging system?
No. The College asks for documentation that the scavenging system was inspected and verified by a qualified technician from an independent third-party company within the previous 24 months, or the manufacturer's interval. That is an anaesthesia-equipment service firm. Our part is the building side: the exhaust duct, fan and outdoor termination that an active scavenging system discharges into.
Can a standard rooftop unit or heat pump serve a vet clinic?
Yes for reception, exam rooms and offices. The wards, isolation and surgery need their own exhaust and supply arrangements on top of it, because a single unit with a common return mixes every room's air. The usual retrofit keeps the existing unit, adds dedicated exhaust fans and a tempered outdoor-air supply, and rebalances the ducts so each room sits at its intended pressure.
How often should filters be changed in an animal hospital?
More often than the quarterly schedule most plazas run. Hair and dander load filters quickly, and a loaded filter reduces the airflow that keeps surgery positive and isolation negative. Check monthly for the first season, note how fast they load, and set the interval from that. Return grilles in treatment and grooming areas need vacuuming between changes.
Related
Keep the building running.
One licensed team for installs, maintenance contracts and 2 AM calls.