Replacing HQL, HQI and Sodium Lamps with LED: Wattage Table and Savings
Replacing mercury vapour, metal halide and sodium lamps with LED: wattage table, retrofit lamps versus new luminaires, extra benefits and a savings example.
Many halls, yards and sports pitches still have luminaires with mercury vapour (HQL), metal halide (HQI) or high-pressure sodium (NAV/HPS) lamps. They take minutes to reach full brightness, use two to three times as much electricity as LED, and replacement lamps are getting scarce. This guide shows which LED wattage replaces which lamp, whether a lamp swap or a new luminaire makes more sense, and how much you save.
- Mercury vapour lamps may no longer be placed on the EU market since 2015; metal halide and sodium lamps are getting scarcer under ecodesign rules.
- Rule of thumb: 250W HQL/HQI → 100W LED, 400W → 150W LED, 1,000W → 300–400W LED.
- System power of the old luminaire is around 8–10% above lamp power because of ballast and ignitor.
- LED retrofit lamps (E27/E40) are possible but often tricky: heat build-up in closed reflectors, ballast must be bypassed.
- A completely new LED luminaire is the safer, longer-lasting solution in most cases.
Which LED replaces which lamp?
| Old lamp | System power (approx.) | LED replacement | Saving |
|---|---|---|---|
| HQL / HQI 150W | approx. 170W | High bay 70W | approx. 60% |
| HQL / HQI 250W | approx. 270W | High bay 100W | approx. 63% |
| HQL / HQI / HPS 400W | approx. 430–440W | High bay 150W | approx. 65% |
| HQI / HPS 600W | approx. 650W | High bay 200–240W | approx. 65% |
| HQI / HPS 1,000W (floodlight, mast) | approx. 1,080W | LED floodlight 300–400W | approx. 65–70% |
The values apply for comparable illuminance on the floor. Because LED is directional and loses no light in the reflector, much less power is needed. In very high halls or with high requirements, a recalculation is worthwhile (see LED High Bay Lighting).
Lamp swap or new luminaire?
LED retrofit lamp (E27/E40)
There are LED lamps with E27 or E40 bases that screw in instead of the HQL lamp. It sounds simple, but there are catches: ballast and ignitor usually have to be bypassed (a job for an electrician), heat builds up in closed reflectors, and the old reflector's light distribution rarely suits the LED. Many retrofit lamps therefore don't reach their promised lifetime.
New LED luminaire
A new LED high bay or floodlight replaces luminaire, ballast and lamp in one go. The suspension is usually identical, and installation takes hardly longer than a lamp swap with rewiring. In return you get optics designed for LED, a defined protection rating, a 5-year warranty and no legacy components in the housing. For larger installations it is almost always the more economical solution.
LED replacements for HQL, HQI and HPS
Benefits beyond electricity
- Full light instantly: HQL and HQI need 3–10 minutes to warm up and even longer after a power cut. LED is on immediately.
- Switching and dimming: Motion sensors and daylight control hardly work with discharge lamps but are easy with LED.
- Maintenance: No more lamp changes every 2–3 years from a cherry picker (see LED Lifetime Explained).
- Better light quality: Sodium light is orange (Ra ~25); LED offers Ra 70–80 and more.
Worked example: warehouse with 30 HQL luminaires
30 × HQL 400W (approx. 430W system power), 4,000 operating hours, €0.28/kWh. Replaced by 30 LED high bays of 150W:
- Saving: 30 × 280W × 4,000 h = 33,600 kWh, around €9,400 a year
- Plus no more lamp changes with a cherry picker every few years
- At typical investment costs, the retrofit usually pays back in 1–2 years
Calculate with your own values: LED Payback Period Calculator.
Frequently asked questions
Can I still buy mercury vapour lamps?
Only remaining stock. High-pressure mercury lamps may no longer be placed on the EU market since 2015.
Which LED replaces a 400W HQL lamp?
Usually an LED high bay of 150W. In very high halls or with high illuminance requirements, 200W can make sense.
Can I simply screw an LED lamp into the old luminaire?
Often technically possible, but the ballast usually has to be bypassed and heat dissipation in the old housing is poor. A new luminaire is the better choice in most cases.
How much does switching from metal halide to LED save?
Typically 60–70% of electricity costs, plus lamp replacement and maintenance costs.
Does this also apply to floodlights on sports pitches?
Yes. Old 1,000W metal halide floodlights are usually replaced by 300–400W LED floodlights. How much light a pitch needs is covered in How Many Lux Does a Football Pitch Need?
Send us the number and wattage of the old luminaires and the mounting height. We recalculate the right LED wattage in DIALux and prepare a no-obligation quote at direct-import prices 2–4× below comparable branded products. 5-year warranty.
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