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Two prices for a rooftop replacement are not comparable until you know what is under the unit
The curb, the flashing, the duct connections and the crane are where commercial quotations diverge, and none of them is visible from the car park.
Small commercial across the South Bay
Light industrial units
Units off the arterials with tall doors, high bays and a process that makes heat. Destratification, spot heating and cooling at the workstation, extraction and make-up air, sized for how the space is worked.
Workshops and trade counters
Where a roller door is open half the day and the counter is beside it. We measure the door schedule before we size anything, because it dominates the calculation.
Offices and suites
Small offices and professional suites, often on a rooftop unit and a zoning system somebody reconfigured years ago. Filter programmes, schedules and a written record per unit.
Shops and showrooms
Door-open trading, west glass and one unit expected to handle both. Honest conversations about air curtains and vestibules, including when they are not worth it for your door.
Restaurants and cafes
Where hood exhaust and dining-room comfort are one problem. We measure the make-up air, because a room that cannot hold temperature at service usually has a building being pulled into a vacuum by its own hood.
Landlords and managers
Attend, diagnose, photograph, price, report, and authorise nothing without your written say-so. Annual condition surveys per unit across a portfolio.
Five items that separate two prices for the same rooftop unit
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The curb
Whether the new unit sits on the existing curb or needs an adapter, and who supplies it. An adapter curb is a real cost and it is frequently left out of the cheaper quotation entirely.
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The roofing
Who flashes around the curb afterwards, and whether that affects a roof warranty. This is the item that most often becomes an argument once the crane has gone.
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The crane
Size, where it stands, whether a street closure or a permit is needed, and whether it has to be at a weekend. On a tight site this can be a large share of the price.
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The duct and electrical connections
Whether the existing transitions and disconnect are reused or replaced, and who verifies the supply is right for the new unit. “Connect to existing” covers a wide range of work.
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Start-up and commissioning
Whether airflow, charge and static pressure are measured and recorded on handover, or whether the job ends when the unit runs. The second one is cheaper and you find out why in July.
A schedule with named months
Filters at an interval that suits your building rather than a default. Coils cleaned, drains proved, belts and contactors inspected, charge and combustion measured, run times checked for cycling, and the readings entered against last year’s.
One document per site listing every unit, where it is, what it serves, its age from its serial number and its last readings. If you change contractor, it goes with you.
