Home / Services / Commercial HVAC / Commercial HVAC Installation & Replacement
Commercial · Commercial HVAC Installation & ReplacementCommercial HVAC Installation & Replacement
Most of a commercial HVAC installation and replacement is settled before the crane arrives: the permit question, the electrical supply, the roof curb and the weight of the new unit. A like-for-like rooftop swap is typically a one-day lift once the equipment is on site, while anything that changes capacity, ductwork or ventilation needs an Ontario Building Code permit first. We make the gas connection under CSA B149.1 with TSSA-licensed technicians, coordinate the electrical and crane work, and hand over a commissioning report with measured airflow.
Three approvals can apply to one commercial unit, and they come from three different places. The municipal building department — City of Burlington, Town of Oakville, City of Hamilton, City of Mississauga and the rest — issues an Ontario Building Code permit when the work changes equipment capacity, ductwork or ventilation; a true like-for-like replacement is often exempt, but the building department makes that call, not the contractor. The Electrical Safety Authority is notified by the licensed electrical contractor who disconnects and reconnects the unit. The gas piping and appliance connection are done under CSA B149.1 by a TSSA-licensed gas technician whose licence class covers the appliance's input.
A commercial replacement has four problems a house never does. The unit goes up by crane, and if the crane has to set up on a public road the municipality wants a road occupancy permit and traffic control arranged ahead of time. The new unit rarely matches the old roof curb, so we measure the curb and order a curb adapter with the equipment, not on lift day. The electrical supply has to match as well — most commercial units are three-phase at either 208 V or 575 V, and the wrong voltage on the order means a unit that goes back on the truck — and when the replacement is heavier than what it replaces, a structural engineer reviews the roof before anything is set down.
Setting the unit on the curb is the midpoint, not the end. Start-up means gas pressure and combustion checked on the heat section, refrigerant readings recorded, supply airflow verified against the design figure, the economizer set up so it brings in free cooling when outdoor conditions allow, and the thermostat schedule programmed to your hours. All of it goes into a commissioning report with model and serial numbers, and we register the manufacturer's warranty while the paperwork is in front of us. On split systems, new condensing units use R-454B or R-32 refrigerant, so the matching indoor coil is replaced along with them.
Incentives for commercial equipment run through different programs than the ones homeowners use. The residential Home Renovation Savings Program does not apply to a business; the routes are the IESO's Save on Energy Retrofit program and Enbridge Gas commercial incentives, and you should confirm each program's application timing before equipment is ordered — our commercial HVAC rebates page tracks them. Cost is driven by tonnage, gas heat input, curb and electrical changes, crane time and controls, so we quote in writing after a roof visit, and what a commercial rooftop unit costs explains the line items. For the wider picture see commercial HVAC, or contact the shop with the model and serial number of the unit you want replaced.
Equipment we install and service
Gas heat and electric cooling in one cabinet on a roof curb, the standard equipment for plazas, offices and light industrial units. We have installed Hisense rooftop units and service the commercial lines from Lennox, Carrier, Trane and York, so a replacement can stay in the family the building already has.
The curb is the raised, flashed frame the unit sits on, with the supply and return duct openings inside it. A curb adapter bridges an old curb to a new unit's footprint without re-cutting the roof, at the cost of some added height and weight that has to be accounted for.
Where there is no roof access or the space has its own furnace or air handler, the cooling is a condensing unit outside and a coil inside joined by a refrigerant line set. Line length, lift and the route through a tenant's ceiling drive the labour more than the equipment does.
The roof gas line, shut-off and regulator, the weatherproof electrical disconnect at the unit and the thermostat or controller inside. Gas piping is pressure-tested before the appliance is fired, and the disconnect is the electrician's scope under the ESA notification.
What goes wrong in these buildings
- The unit is nineteen years old and the latest repair quote is a third of the price of a new one.
- I have three quotes and none of them mention a permit, a crane or the curb.
- The tenant cannot close for a day, so the lift has to happen before they open.
- The crane can only set up on the street side and nobody has said who arranges the road occupancy.
- Our last installer left no start-up report and the manufacturer is asking for one on a warranty claim.
- I was told there is rebate money for this and I do not know which program it is or who applies.
How it works
Nameplate data, curb dimensions, supply voltage, gas line size, duct connections and where a crane can stand. The quote lists permit, crane, curb adapter, electrical, refrigerant recovery and disposal as separate lines so competing quotes can be compared item by item.
Permit application where the building department requires one, road occupancy if the crane needs the street, and the landlord's roofer booked for any flashing work. Refrigerant in the old unit is recovered by an ODP-certified technician, then the old unit comes off and the new one goes on in the same lift.
Gas pressure, combustion, refrigerant readings and supply airflow are measured and written down, the economizer and thermostat schedule are set, and the warranty is registered. You receive the commissioning report, the permit closure if there was one, and the first filter-change date.
Common questions
Do I need a building permit to replace a rooftop unit in Ontario?
Often not for an identical-capacity replacement on the existing curb, gas line and ductwork, and usually yes when capacity, ductwork, ventilation rates or the structure change. Municipalities interpret this differently, so we ask the building department for your address before ordering. The gas work and the electrical notification apply either way, permit or no permit.
How long is the space without heating or cooling during a replacement?
For a like-for-like rooftop swap, plan on one working day: the old unit is disconnected and lifted off, the new one is set, connected, started and tested. Curb changes, gas re-piping or an electrical upgrade can add a second day. The longer wait is equipment delivery, so a failing unit is often kept running with a temporary repair until lift day.
Should I replace one failing unit or every unit on the roof at once?
Replace only the failed unit when its neighbours are under about twelve years old and in sound condition. When several are past fifteen years, group them: the crane, the road occupancy and the roofer are paid for once instead of three times, and the units share a warranty start date and a service schedule. We price both options side by side.
Can a new unit sit on the existing roof curb?
Only when the new cabinet's footprint and duct openings match, which is rare across manufacturers and even across generations of one brand. Otherwise a curb adapter is built to the two sets of dimensions. Before relying on the old curb we check that its flashing is sound and its frame is not rusted through, because a new unit on a leaking curb is a roof claim waiting to happen.
Related
Keep the building running.
One licensed team for installs, maintenance contracts and 2 AM calls.