Typical Energy Savings for Lighting Retrofit Measures
Summarised from the IEA SHC Task 50 review of real-world lighting retrofits.
Source: IEA SHC Task 50 – Technical Report T50.D2 (2016)
For reducing energy use in buildings, lighting is often one of the simplest and most measurable places to start. But how much can you actually save — and which measures deliver the biggest impact in real projects?
To find out, we looked at the IEA SHC Task 50 Technical Report, one of the most comprehensive international reviews of lighting retrofits conducted across Europe and beyond. The report gathered results from field studies, lab tests, and post-occupancy evaluations to quantify how different retrofit strategies perform in practice.
1. Lighting accounts for a large share of building energy use
The review found that lighting makes up anywhere from 15% to 60% of total energy use in non-residential buildings, depending on type and operating hours.
Offices and schools sit near the lower end of that range; retail and healthcare facilities are often much higher.
That means improvements here have a visible impact on the overall carbon footprint of a building — particularly when electricity is still generated from a mixed grid.
2. LED replacement remains the single biggest opportunity
Across dozens of studies, LED retrofits consistently delivered around 50% energy savings compared with older fluorescent or HID systems.
This figure aligns with what we see in practice at Lumenloop when older T8 and T5 fittings are replaced with high-efficacy LED luminaires.
However, it’s not just about wattage: modern LED systems offer better optical control and lumen maintenance, meaning fewer fittings can often achieve the same visual performance.
3. Smarter lighting layouts save more than you think
One of the most interesting findings from the IEA review was the benefit of task-ambient design — providing higher light levels only where they’re needed and reducing background illumination elsewhere.
These schemes delivered 22–25% energy reductions compared with standard efficient general lighting, without compromising comfort or usability.
In other words, layout and design strategy matter almost as much as the technology itself.
Where Lighting Energy is Used
Based on the IEA SHC Task 50 analysis of lighting system energy use components.
Source: IEA SHC Task 50 – Technical Report T50.D2 (2016)
4. Controls work — but context is everything
Occupancy sensors, daylight dimming, and presence detection were also studied extensively. Reported savings ranged from 20% up to over 90%, depending on the building type and how the system was commissioned.
That range highlights a key point: controls can be transformative, but only when they’re configured for how people actually use a space. Poorly tuned sensors or overrides can quickly erode those expected gains.
5. Paybacks are typically under two years
Perhaps the most persuasive figure from the IEA analysis: most lighting retrofit projects achieved payback in less than two years.
That’s a compelling statistic in any energy management plan — and a reminder that efficiency doesn’t have to be a long-term gamble.
Turning research into action
At Lumenloop, we believe the best lighting strategies start with real data and end with practical results.
Whether you’re looking to upgrade an existing estate or design new lighting around energy targets, the evidence is clear: thoughtful retrofit design delivers rapid, measurable savings.
If you’re interested in reviewing your current setup or exploring a lighting plan aligned with the findings above, you can get in touch with our team — we’re happy to share insights or model what those savings could look like for your buildings.
Sources:
IEA SHC Task 50, Technical Report T50.D2 — Daylighting and Lighting Retrofit to Reduce Energy Use in Non-Residential Buildings, 2016.
