💡 Wattage Reduction
Savings Breakdown
Full Calculation Table
| Value | Existing | LED |
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How to Use the LED Retrofit Calculator
Pick the closest match, or use Custom to enter the exact existing system wattage including ballast losses if you know it.
Use the actual wattage from the LED product's spec sheet rather than an estimate, since LED wattage varies widely between products at similar light output.
Mechanical rooms and equipment areas often run lights for long hours or continuously, which has a big effect on the payback calculation.
Enter the total retrofit cost and any utility rebate to see a simple payback period alongside the annual savings.
Why Mechanical Rooms Are Good LED Retrofit Candidates
Mechanical rooms, equipment closets, and rooftop unit access areas often have lighting that runs for long hours, sometimes nearly continuously during business hours or whenever staff might need access. That heavy usage pattern is exactly what makes an LED retrofit pay back quickly, since the savings accumulate every single hour the lights are on rather than just during occasional occupancy.
Comparing Fixture Wattages
A typical 4-foot, 2-lamp T8 fluorescent fixture draws around 59 W including ballast losses, while the older T12 equivalent draws closer to 96 W. A 400 W metal halide HID fixture, common in larger mechanical rooms and equipment bays, draws around 458 W once ballast losses are included. LED replacements for these fixtures commonly land in the 25 to 32 W range for tube replacements and 100 to 200 W range for HID high-bay replacements, though the exact figure depends heavily on the specific product and the light output it's rated to match. Always check the actual spec sheet wattage rather than assuming a generic LED replacement number, since LED products vary more in efficiency than older fluorescent and HID technology did.
The Simple Payback Calculation
Simple payback divides the total upfront retrofit cost, minus any rebate, by the annual dollar savings from reduced energy use. It doesn't account for the time value of money or financing costs, but it's a fast, intuitive way to compare retrofit options and decide whether a project makes financial sense before committing to it. Spaces with long operating hours, like mechanical rooms that run lighting most of the business day or around the clock, tend to show the shortest payback periods because the energy savings accumulate so quickly.
Don't Forget Utility Rebates
Most Canadian utilities offer some form of rebate or incentive program for commercial LED retrofits, and these can meaningfully shorten the payback period. Check with the local utility serving the building before finalizing a retrofit budget, since rebate programs and amounts change periodically and vary significantly by province and even by specific utility territory.
Beyond Energy Savings
LED fixtures also typically last far longer than fluorescent tubes or HID lamps, which cuts down on the maintenance cost and labour of replacing burned-out lamps and ballasts over time. This maintenance saving isn't included in this calculator's payback estimate, but it's worth factoring in separately for a fuller picture of the retrofit's total value, especially in hard-to-access mechanical spaces where a service call to replace a lamp carries real labour cost.
Next Steps
Once you've confirmed the LED wattage, check the lighting power density tool to confirm the retrofit still complies with energy code maximum lighting power limits, and the amperage calculator if you need to confirm the existing circuit can handle the new (typically lower) lighting load.
Frequently Asked Questions
A typical LED retrofit cuts lighting wattage by 40% to 65% compared to T12 or T8 fluorescent fixtures, and by 50% to 70% compared to metal halide or high pressure sodium HID fixtures, while often producing equal or better light output. The exact savings depend on the specific fixtures being replaced and the LED product chosen, so always compare actual wattage and lumen ratings rather than relying on a single rule of thumb.
Mechanical rooms and equipment areas often run lighting for long hours, sometimes continuously, which shortens the payback period compared to spaces used only occasionally. A simple payback of 2 to 4 years is common for these high-usage spaces, though the exact figure depends on the local electricity rate, the wattage reduction achieved, and any utility rebate that offsets the upfront retrofit cost.
Usually not, since LED retrofits almost always reduce the connected load rather than increasing it, meaning existing wiring and breakers stay within their rated capacity. The main wiring consideration is whether the retrofit eliminates the ballast entirely, in which case the fixture's internal wiring needs to be reconfigured for direct line voltage to the LED driver, which is a straightforward but necessary part of a proper retrofit installation.
Most Canadian utilities and several provincial energy efficiency programs offer rebates for commercial LED retrofits, though the exact amount and eligibility rules vary by province and utility territory and change periodically. Check directly with the utility serving the building before finalizing a retrofit budget to get the current rebate amount.
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