At 7 pm, many offices are still fully lit despite only a small cleaning crew remaining on site. That single operating pattern can turn an otherwise efficient lighting upgrade into a missed savings opportunity. This office retrofit savings example shows how a considered LED upgrade, supported by suitable controls and realistic operating data, can reduce electricity and maintenance costs without compromising workplace illumination.
The figures below are indicative only. Electricity tariffs, operating hours, fitting selection, access requirements and available energy-efficiency incentives vary by site. A lighting audit is required to establish an investment case for a specific building.
Office retrofit savings example: a 2,000 m² workplace
Consider a two-level, 2,000 m² metropolitan office occupied by approximately 180 staff. The existing lighting system comprises recessed 4 x 18 W fluorescent troffers, with many fittings operating at roughly 80 W once ballast losses are included. The building has limited local switching, no occupancy sensing in meeting rooms or amenities, and lights are routinely left on after business hours.
The facilities team reports rising maintenance call-outs for failed tubes and ballasts. Staff have also raised concerns about inconsistent light levels, particularly around workstations near the perimeter of the floorplate.
A retrofit design replaces 500 fluorescent troffers with LED office panels selected to meet the required illuminance and glare criteria for desk-based work. The new fittings have a system load of 36 W each. Occupancy sensors are installed in meeting rooms, utility rooms and amenities, while time scheduling is applied to general office areas.
Baseline and proposed energy use
The existing installation draws approximately 40 kW:
| Measure | Existing fluorescent system | Proposed LED system | |—|—:|—:| | Number of fittings | 500 | 500 | | Average system wattage per fitting | 80 W | 36 W | | Connected lighting load | 40 kW | 18 kW | | Annual operating hours | 3,000 hours | 2,700 hours | | Annual lighting energy use | 120,000 kWh | 48,600 kWh |
The LED system reduces connected load by 22 kW. Controls also reduce annual operating hours by 10 per cent, reflecting better shutdown of lightly used spaces and reduced after-hours operation.
Annual energy consumption falls from 120,000 kWh to 48,600 kWh. That is a reduction of 71,400 kWh each year, or approximately 59.5 per cent. The result comes from two sources: lower wattage and fewer unnecessary operating hours. Either measure has value, but together they produce a more meaningful commercial outcome.
Converting kWh savings into dollar savings
For this example, assume a blended electricity cost of $0.28 per kWh. This should include the site’s applicable network and retail charges where possible, rather than relying on a simple headline energy rate. Large commercial customers may have more complex tariff structures, including demand charges, so the financial model should reflect actual invoices.
At $0.28 per kWh, the annual electricity saving is:
71,400 kWh x $0.28 = $19,992 per year
Energy savings alone do not tell the whole story. Fluorescent lighting creates an ongoing maintenance burden, particularly where fittings use multiple tubes and electronic ballasts. A failed component can also leave a workstation poorly lit until access, parts and labour are arranged.
Assume the current installation requires $7,500 annually for replacement tubes, ballasts, labour and access. The LED installation is expected to require $1,800 per year for periodic servicing and isolated failures over the same early operating period. This produces an estimated maintenance saving of $5,700 annually.
The combined annual operating saving is therefore approximately $25,692.
| Annual cost item | Existing system | LED retrofit | Annual saving | |—|—:|—:|—:| | Electricity | $33,600 | $13,608 | $19,992 | | Maintenance | $7,500 | $1,800 | $5,700 | | Total annual operating cost | $41,100 | $15,408 | $25,692 |
What does the payback look like?
Assume the supply, installation, controls, commissioning and disposal of the existing fittings cost $82,000. This budget must be treated as an example, not a standard project rate. Office access conditions, ceiling type, electrical switchboard capacity, emergency-lighting requirements and the need for after-hours works can materially affect installed cost.
With annual savings of $25,692, the simple payback is approximately 3.2 years.
For many property and facilities teams, that is a reasonable starting point rather than the final decision metric. A stronger business case also considers the expected LED service life, reduced disruption from maintenance activity, improved light consistency and the potential effect of controls on future operating costs. Where an eligible project can access support through an applicable state energy-savings scheme, the upfront cost may reduce further. Scheme eligibility, certificate values and compliance requirements must be confirmed before they are included in financial forecasts.
Why the design matters as much as the fitting wattage
A low-wattage fitting does not automatically deliver a successful office upgrade. Offices need appropriate illumination for screens, paper-based tasks, meeting spaces, circulation zones and shared amenities. Poorly specified panels can create glare, uneven distribution, excessive contrast or an appearance that occupants find uncomfortable.
The design process should begin with the activities performed in each zone. Open-plan work areas commonly require a different lighting arrangement from boardrooms, reception areas, kitchens and enclosed offices. Ceiling height, surface reflectance, daylight availability and desk layouts all influence the final fitting layout.
Colour temperature also needs a practical assessment. A neutral white output is often selected for commercial office environments, but the preferred result depends on the organisation’s existing fit-out, finishes and the nature of the work undertaken. Uniformity, glare control and colour rendering should be assessed alongside watts and lumens.
Emergency lighting must be addressed separately. A general lighting retrofit may affect existing emergency fittings, circuit arrangements or compliance documentation. The project scope should identify whether emergency lighting is being retained, upgraded or tested as part of the works.
Controls are not optional in the right spaces
In the example above, controls contribute around 5,400 kWh of the annual saving. Their value will differ between buildings. A densely occupied office operating predictable hours may gain most from reliable time scheduling, while meeting rooms, amenities, storage areas and breakout spaces are well suited to occupancy sensing.
Daylight harvesting can also be effective in perimeter zones with consistent natural light. However, it requires careful commissioning. If sensors are poorly positioned or programmed too aggressively, occupants may experience noticeable brightness changes or feel that their work area is underlit. The objective is controlled reduction, not constant visible adjustment.
Facilities teams should retain straightforward override options for cleaners, security personnel and approved after-hours users. Controls must support how the building operates in practice, not impose a theoretical schedule that staff work around.
Inputs that can change the savings result
This office retrofit savings example uses conservative, understandable assumptions, but every site will produce a different result. Higher operating hours increase the value of reduced wattage. A building with fluorescent fittings operating 14 hours a day, six days a week will generally produce a faster payback than a lightly used tenancy with short weekday hours.
Electricity pricing has the same effect. Sites with higher blended energy costs may see a stronger annual saving, although tariff structures should be reviewed carefully. In some buildings, lighting also contributes to cooling load. Lower lighting heat output can reduce air-conditioning demand, but that benefit depends on the HVAC system, climate, occupancy and building controls. It should not be assumed without assessment.
Maintenance savings likewise depend on access. Replacing a failed fitting above standard office ceilings is relatively straightforward. Servicing lighting in high atriums, active trading areas or restricted-access spaces can be substantially more expensive, making reliable LED equipment more valuable.
Building a defensible retrofit proposal
A useful proposal starts with measured site information rather than catalogue comparisons. Record the existing fitting types, actual wattages, quantities, operating schedules, room uses and switching arrangements. Review recent electricity invoices, identify maintenance history, and confirm any tenant, landlord or base-building responsibilities.
The proposed design should show fitting locations, lighting levels, control zones, emergency-lighting treatment and installation assumptions. It should also state the basis for energy calculations, including operating hours and electricity rates. This allows a facilities manager, asset owner or procurement team to test the assumptions rather than accept a broad percentage-saving claim.
Installation planning is equally important in occupied workplaces. Staged after-hours works, dust management, access coordination and communication with tenants can protect productivity while reducing project risk. The supplier should also provide commissioning, relevant compliance documentation and a clear point of contact for post-installation support.
For commercial portfolios, the best next step is usually a site audit that turns broad savings potential into an accountable project scope. EO Lighting can assess existing lighting, model likely energy savings and develop a design that balances operational cost reduction with the lighting quality people need to work effectively.