LED lamps: how to choose the right replacement (base, colour temperature, flicker)

Short Answer

To replace an incandescent or halogen bulb with an LED version, you only need to check four things: the base (most commonly E27 or E14), the luminous flux in lumens instead of the traditional wattage, the colour temperature suited to the room's purpose (2700–3000 K for living areas, 4000 K for workspaces), and—if the luminaire is controlled by a dimmer—a clear "dimmable" indication on the packaging. A standard LED bulb will not work with a dimmer.

When calculating power requirements, use lumens as your guide. Based on typical product ranges, a 60 W incandescent bulb (approx. 700 lm) can be replaced by an 8 W LED; a 75 W bulb by a 10 W LED; and a 100 W bulb by a 13–15 W LED. The "divide wattage by ten" rule is only an approximation for modern lamps: models with the same wattage can have luminous fluxes that differ by a factor of 1.5 to 2, so always check the lumens specified on the packaging.

Step 1. The Base: What fits your luminaire

The base is the only parameter where an error means the bulb physically will not fit. Within the "LED lamp" category, there are dozens of base types; here are the most common ones:

If you are replacing an old lamp, simply check the marking on the base or measure it: E27 has a 27 mm thread diameter, E14 has 14 mm, and for pin-type bases, the number in the name indicates the distance between the pins in millimetres (e.g., 5.3 mm for GU5.3, 9 mm for G9).

Step 2. Watts and Lumens: A Reliable Replacement Guide

For LED lamps, wattage represents power consumption, not brightness. Brightness is measured by luminous flux in lumens (lm). We have compiled the actual luminous flux values from manufacturers' data for each power level; the table below shows the median values:

Incandescent lamp	Required luminous flux	LED replacement	Median flux for LED lamps of this power in the catalogue
40 W	approx. 400–450 lm	5 W	450 lm
60 W	approx. 700–750 lm	8 W	720 lm
75 W	approx. 900–950 lm	10 W	900 lm
100 W	approx. 1300–1400 lm	13–15 W	1200–1435 lm
150 W	approx. 2100 lm	20–25 W	1890–2400 lm

Important note: there is a significant variance within a single power rating. Among 10 W lamps in the catalogue, the luminous flux ranges from 650 to 1600 lm—a 2.5-fold difference. A budget 10 W lamp may perform as poorly as a high-quality 7 W lamp. Therefore, when replacing bulbs, compare lumens; use wattage only as an estimate for energy consumption. The typical luminous efficacy of modern lamps in our range is approximately 90–100 lm/W.

A flux margin of 10–15% during replacement is advisable: for some lamps, the stated flux is specified for cool white light, whereas the same model in a warm colour temperature may produce slightly less light.

Step 3. Colour temperature: which light for which room

Temperature	Shade	Application
2700 K	warm, like an incandescent lamp	Bedroom, living room, floor lamps and wall lights, evening lighting
3000 K	warm white	Living areas, kitchen-dining areas, corridors — a versatile "home" option
4000 K	neutral white	Kitchen work areas, study, bathroom, office, retail space
6500 K	cool, with a bluish tint	Garage, workshop, warehouse, technical and industrial premises

Two practical rules. First: do not mix lamps with different colour temperatures in a single room, and especially not within the same luminaire—the difference between 3000 K and 4000 K is immediately noticeable and looks like a defect. Second: 6500 K cool light is rarely appropriate for home use—it feels subjectively brighter, but makes it harder to relax in the evening. For living areas, choose 2700–3000 K; for workspaces, choose 4000 K.

Step 4. Flicker: the invisible parameter you can feel

The flicker coefficient indicates how much the luminous flux "flickers" at the mains frequency and its harmonics. While the eye cannot perceive flicker above ~100 Hz, high flicker levels cause faster eye fatigue and can trigger headaches in sensitive individuals. Furthermore, a stroboscopic effect may occur—rotating parts of machinery might appear stationary, which is a direct safety hazard in a workshop.

Lighting requirements for indoor spaces are governed by local hygiene standards and lighting regulations: for most workspaces, the flicker coefficient is limited to 10–20% depending on the nature of the visual task, while for computer workstations, it must not exceed 5%.

How to apply this when choosing:

• High-quality lamps with built-in drivers (stabilised constant current sources) have flicker levels of only a few per cent—these can be used anywhere, including offices with monitors.
• Cheap lamps with simple capacitor-based ballasts can flicker by tens of per cent. This is not always stated in the markings; an indirect sign of the problem is "rainbow" bands appearing when filming the lamp with a smartphone camera.
• For children's rooms, offices, and workstations, look for an explicit indication of low flicker in the technical specifications; for storerooms or outdoor luminaires, this parameter is less critical.

Step 5. Dimming and other special cases

A standard LED lamp will not work with a dimmer (brightness regulator): it will flicker, hum, or simply fail to ignite at low brightness, while both the lamp driver and the dimmer undergo accelerated wear. For adjustable lighting, you need a lamp explicitly labelled as "dimmable"—these are available on the market, ranging from 7 W E14 candle shapes to 11–12 W A60 pear shapes. The dimmer itself must be compatible with LED loads: pay close attention to the regulator's minimum load capacity.

Three more specific cases:

• Switches with indicator lights. The leakage current from the indicator light passing through the switched-off lamp can cause certain models to flash or glow dimly in the dark. This can be resolved by disabling the switch's indicator light or by selecting a lamp designed to be resistant to this effect.
• Enclosed and high-temperature luminaires. LEDs are sensitive to overheating; in a small, tightly enclosed luminaire, the lamp's service life is significantly reduced. While most lamps on the market have a rated lifespan of 25,000–30,000 hours, this is only achievable with adequate cooling.

Common selection errors

1. Matching by wattage "as before". An advertising claim like "10 W = 100 W incandescent" actually delivers only 650–900 lm, which is equivalent to a 60–75 W bulb. Always compare lumens instead.
2. Different colour temperatures in a single chandelier. Purchasing a "matching 10 W lamp" only to find it is 4000 K instead of 3000 K will make the chandelier look faulty. Check the Kelvin rating, not just the power.
3. Standard lamps on a dimmer. This leads to flickering and premature failure. Use only models explicitly marked as "dimmable".
4. 12 V MR16 in a 230 V socket (or vice versa). While the GU5.3 base may look identical, the voltage is different. Always check if the luminaire contains a transformer.
5. 6500 K in living areas. "Cool" lamps may appear brighter at the same luminous flux, but this light is fatiguing for domestic environments. For living rooms, use 2700–3000 K.
6. Neglecting flicker for workspaces. For computer desks or children's rooms, select lamps with low flicker ratings, as requirements for these areas are the most stringent (typically up to 5%).
7. Ignoring dimensions. An LED "A-shape" or reflector bulb may be longer than the incandescent bulb it replaces, causing it to hit the shade. Always verify the length and diameter in the technical specifications.

Example: three E27 lamps for different tasks

A practical comparison from manufacturers' data: three E27 "A-shape" or "globe" bulbs with different colour temperatures and colour rendering indices (CRI) — warm for a living room, neutral with high CRI for a kitchen/study, and cool for utility rooms.

Conclusion: Replacement Checklist

1. Identify the base type using the markings on your old lamp (E27, E14, GU5.3, GU10, G9, G4, GX53, G13, E40).
2. Find the required luminous flux: a 60 W incandescent equivalent is approximately 700 lm, 75 W is 900 lm, and 100 W is 1300 lm.
3. Select the colour temperature: 2700–3000 K for living areas, 4000 K for workspaces, and 6500 K for technical areas.
4. For dimmable setups, use only dimmable models; for workspaces, choose low-flicker options; for visible lamps, consider filament LEDs.
5. Check dimensions and operating conditions: enclosed fixtures, humidity (ensure appropriate IP rating per EN 60529), and temperature.