LED Retrofit for Outdoor and Street Lighting

Replacing high-pressure mercury vapour, sodium vapour or halogen outdoor luminaires with LEDs.

How does converting street lighting to LED work?

In the conversion, outdoor luminaires with high-pressure mercury vapour lamps (HQL), sodium vapour lamps or halogen are replaced by LED luminaires. A classic 125 W mercury vapour luminaire draws around 145 W including ballast; the LED luminaire for the same lighting task manages with 35 to 45 W. Street lights typically operate around 4,000 hours a year; in Austria, 4,100 h/a is used as the standard value. Usually only the luminaire head on the existing column is replaced, occasionally the control cabinet is modernised too. LED luminaires also offer functions that were not possible with discharge lamps: they can be dimmed during the night hours, for example to 50 % between 11 pm and 5 am, and their asymmetric light distribution directs the light onto the carriageway rather than into the sky. This reduces light pollution and energy consumption at the same time.

Which operators benefit from LED street lighting?

Typical users are municipalities and operators of industrial sites, car parks and larger outdoor facilities. The existing column must be suitable for the new luminaire; existing LED lighting is excluded. For municipalities, the measure is particularly relevant, because street lighting accounts for a substantial share of their electricity costs. In Austria, the domestic environmental support scheme (Umweltförderung im Inland), administered by Kommunalkredit Public Consulting, supports the LED conversion of street and outdoor lighting; some federal states have complementary programmes. Professional lighting design to ÖNORM EN 13201 is a prerequisite for funding and standard-compliant illumination.

What does LED street lighting actually deliver?

Electricity consumption falls by 60 to 80 %. A municipality replacing 200 HQL luminaires of 125 W with 40 W LED saves around 86,000 kWh/a and 13.4 t CO2/a. Further savings are possible with night-time dimming. An LED street luminaire costs €200 to €450 plus €100 to €200 for installation. Payback is 5 to 10 years, with a service life of 20 years. On top come significantly lower maintenance costs, because the regular lamp replacement required for discharge lamps is eliminated.

Energy carrier

Strom → Strom

Savings potential

60-80 %

Worked example

A municipality operates 200 street lights with 125 W HQL mercury vapour lamps, each drawing 145 W including ballast. The luminaires operate on astronomical time control from dusk until morning, in line with the Austrian standard value of 4,100 hours per year. As part of the conversion, the luminaire heads on the existing columns are replaced by 40 W LED luminaires that meet the same lighting class under ÖNORM EN 13201. The saving is derived from the power difference, operating hours and number of luminaires: (145 − 40) × 4,100 × 200 / 1,000 = 86,100 kWh/a. Street lighting electricity consumption therefore falls by around 86,000 kWh/a, which at 0.156 kg CO2/kWh corresponds to roughly 13.4 t CO2 per year. Additional night-time dimming would increase the figure further.

Investment & payback

Straßenleuchte LED 200-450 € + Montage 100-200 € · Service life: 20 a · Payback: 5-10 a

Applicability

Requirements

Exclusion criteria

Typical buildings

Frequently asked questions

How much electricity does LED street lighting save?

Converting to LED reduces street lighting electricity consumption by 60 to 80 %. A 125 W HQL luminaire draws 145 W including ballast, the LED replacement only around 40 W. With 200 luminaires and 4,100 operating hours a year, that comes to around 86,000 kWh/a. Night-time dimming increases the saving further.

How much does converting street lighting to LED cost?

An LED street luminaire costs €200 to €450, with installation adding €100 to €200 per luminaire. For 200 luminaires, the investment is therefore €60,000 to €130,000 before subsidies. Payback is 5 to 10 years over a 20-year service life; eliminated lamp replacements and subsidies shorten it.

Are there subsidies for LED street lighting in Austria?

Yes, the domestic environmental support scheme (Umweltförderung im Inland), administered by Kommunalkredit Public Consulting (KPC), funds the LED conversion of street and outdoor lighting for municipalities. Individual federal states such as Lower Austria, Upper Austria and Burgenland offer complementary programmes. A prerequisite is generally professional lighting design to ÖNORM EN 13201 before conversion.

Can LED street lights be dimmed at night?

Yes, unlike mercury or sodium vapour lamps, LED luminaires can be dimmed continuously. Night-time reduction to around 50 % between 11 pm and 5 am is common, either via a profile stored in the driver or via a control system. This saves additional energy, reduces light pollution and is compatible with ÖNORM EN 13201 if the lighting class is adjusted for low-traffic periods.

Does the column need replacing when switching to LED?

In most cases, no. If the existing column is structurally sound and suitable for the usually lighter LED luminaire, only the luminaire head is replaced. This keeps costs and construction time low. Checking the column structure and wiring is nevertheless advisable, since with very old installations corrosion or unsuitable mountings may require replacement.

Standards & sources

Metering points in the EDM Toolbox

Zentrale Steuerschränke mit Zähler ausstatten; Astro-Zeitsteuerung dokumentieren. Optional Dimmungsprofile via Leitsystem - LineMetrics-Logger ergänzt Lichtmast-Zähler über Modbus.

All measures