Step-by-Step Filter Change-Out for Rooftop Package Units in Shopping Centres

For shopping centres, rooftop package unit filter change-outs need more than a quick swap. Access constraints, nearby plant, public areas and tenant trading all mean the job has to be planned carefully, with good housekeeping and clear communication before anyone opens a unit.

This guide outlines a practical process for mechanical contractors and shopping centre managers who want a cleaner, safer and more controlled filter change-out. Total Air Filtration is a family-owned air filter manufacturer and supplier in Hillcrest, Brisbane QLD, and we work with commercial sites that need the right filters, the right dimensions and a sensible service approach.

Plan the job before anyone goes to the roof

A smooth filter change-out starts well before the hatch is opened. On shopping centre rooftops, the main risks are not just dirt and debris, but disruption to tenants, interference with other services and accidental damage to nearby equipment.

Before the visit, confirm:

• •which rooftop package units are due for inspection or filter replacement
• •the access route, roof safety requirements and permit process
• •whether nearby contractors will also be working on the roof
• •where the old filters will be bagged, stored and removed from site
• •whether there are pressure gauges or monitoring points already installed
• •whether the site uses standard sizes or custom air filters

If the site is part of a larger maintenance programme, it can help to review the wider filter servicing approach before scheduling the works. If the existing filters are unusual in size or construction, check whether custom air filters are needed rather than forcing a standard product into the frame.

Confirm the unit details and filter dimensions

Rooftop package units in shopping centres are often crowded into limited roof space, and not every unit is identical. Even small differences in frame depth, locking arrangement or access panel design can make the change-out slower than expected if the replacement filters have not been checked beforehand.

Before loading replacements onto the roof, confirm:

• •the filter type currently installed
• •the exact length, width and depth required
• •the number of filters per unit
• •the frame or track arrangement
• •airflow direction and any marked side orientation
• •whether the filter is disposable or whether some filters are designed to be washable, in which case check the product instructions

If you are measuring an existing filter or housing, use the guidance on how to measure an air filter so the replacement matches the actual opening, not just the nominal size written on the frame. A small sizing error can lead to bypass, difficult installation or damaged seals.

Protect tenants, services and surrounding equipment

Shopping centres are busy operating environments, so the work area needs to be controlled before the first panel comes off. Dust, loose media and packaging can all travel farther than expected on an exposed roof, especially around condenser coils, electrical gear and intake points.

Practical protection measures include:

• •placing tools and new filters in a clean staging area away from edges and air intakes
• •covering nearby equipment that could be affected by dust or debris
• •keeping packaging, old media and tape contained as the job progresses
• •avoiding open storage of used filters on the roof
• •checking that removed filters cannot blow across the roof in wind gusts

Where the rooftop package units serve common areas or tenancies that are sensitive to interruption, it helps to sequence the work so only one unit or one section is open at a time. That reduces the chance of leaving a system exposed longer than necessary.

If the site has a broader servicing programme, commercial filter servicing can help keep the process organised across multiple units.

Remove the old filters carefully

Once the unit is isolated and safe to access, open the filter section slowly and inspect the condition of the filter bank before removal. This is a useful point to look for dirt tracking, damaged seals, corrosion, loose clips or signs that air has been bypassing around the frame.

Good removal practice is simple, but important:

• •pull each filter out without shaking it loose
• •keep the dirty side contained as much as possible
• •place the old filter straight into a disposal bag or lined bin
• •avoid dragging it across the casing or duct opening
• •check whether the frame or gasket has torn, compressed or shifted

If a filter is heavily loaded with dust, handle it so the debris stays in the bag rather than on the roof. Used filters should not be left near air intakes, doorways or other plant, even for a short time, because wind can move loose material around the rooftop.

Inspect the housing before installing the new filters

A filter change-out is also the right time to check the condition of the filter housing. If the frame is bent, the rails are worn or the gasket surface is uneven, even a good replacement filter may not seal properly.

Look for:

• •damaged holding clips or retainers
• •cracks, gaps or corrosion in the filter frame
• •missing seals or compressed gasket material
• •signs of dust bypass around the edges
• •obstructions that could prevent the new filter seating fully

If the rooftop package unit has pressure gauges fitted, note the readings before and after the change-out so the site can monitor pressure drop over time. Inspection frequency depends on the system, site conditions and dust load, and should follow the filter and equipment manufacturer instructions.

For sites that need to align with ventilation requirements, confirm local expectations with the mechanical services engineer or building owner and consider the site’s needs against AS 1668.2:2024.

Install the new filters correctly

A clean installation matters just as much as a clean removal. The best replacement filter will still underperform if it is fitted backwards, pinched, bowed or left with gaps around the perimeter.

When fitting the new filters:

• •check the airflow direction arrow before installation
• •seat the filter squarely in the frame or track
• •make sure the edges sit evenly and do not buckle
• •secure clips, latches or access panels properly
• •confirm there is no visible gap around the filter perimeter

If the unit uses multiple filters in one bank, keep the same orientation across the set unless the manufacturer specifies otherwise. Where a filter is designed to be washable, follow the cleaning and drying instructions exactly rather than improvising on site.

After installation, close the access panel and confirm it is fully latched. A poor seal at the access point can undo the effort spent on the filter change-out.

Finish with a proper handover

A good rooftop filter change-out does not end when the access door is shut. The contractor and site manager should both know what was installed, what was observed and what needs attention next.

A sensible handover includes:

• •the filter type and size fitted to each unit
• •any damaged frames, seals or retainers noted during the job
• •the gauge or pressure reading at completion, if available
• •any rooftop housekeeping issues that should be corrected
• •any units that may need closer monitoring before the next inspection

This record helps the centre maintain consistency across multiple units and makes future servicing faster, especially when different units have different filter sizes or access arrangements.

Work with a supplier who understands commercial rooftop units

Rooftop package unit filter change-outs are easiest when the replacement filters match the equipment and the site workflow from the start. Total Air Filtration, a family-owned air filter manufacturer and supplier in Hillcrest, Brisbane QLD, can supply the right filters or make the right filters for your site.

If you need help with sizing, product selection or a commercial servicing program, call 07 3800 3448 or request a quote. You can also review our products or contact us to discuss the requirements for your shopping centre rooftop units.