Read the luminaire's technical specifications: diameter, base, class, IP rating
A lighting product sheet lists a dozen technical specifications, yet most buyers only read two: the price and the diameter. However, that is where the information is found that determines whether the light will fit in your home, whether it will be installed without issue, and what kind of light it will provide. Here is how to read each line, and the five points to check before ordering.
Dimensions: diameter, height, adjustable height
The diameter is compared to your room: add the length and width in meters, multiply by 10, and you get the recommended diameter in centimeters. As for the height, it should be read carefully: some spec sheets provide the height of the fixture body alone, while others provide the total height including the cable.
When a spec sheet mentions an adjustable height, the cable or chain can be shortened during installation: this is a real convenience, especially under a low or sloped ceiling. The rules for room-by-room proportions are included in our guide on choosing the right chandelier size.
Weight: the line that determines the mounting
This is the information most often ignored, and the one that causes the most unpleasant surprises. A glass chandelier commonly weighs between 5 and 25 kg. Under two or three kilos, a plasterboard ceiling with suitable wall plugs may suffice; beyond that, you must reach the framework or structure.
Therefore, always compare the stated weight with what your ceiling can support, as explained in our articles on mounting on a stretch or plasterboard ceiling and on fixtures under exposed beams.
The base: E14, E27, G9 or integrated LED
The letter indicates the type of connection, the number the diameter in millimeters. E27 is the large screw base, E14 the small screw base found on the majority of multi-arm chandeliers, and G9 a small pin base used on compact models.
A mention of "integrated LED" means that the light source is not replaceable: the lifespan of the fixture becomes the lifespan of its LED. This is not a deal-breaker, but it changes the calculation over fifteen years, as we detail in our article on the consumption of a chandelier.
Number of sources and maximum wattage
The number of sockets determines the distribution of light more than its quantity. The maximum wattage indicated per socket, often 40 W, corresponds to a technical limit inherited from incandescent bulbs: with 4 to 5 W LEDs, you are nowhere near that.
To estimate the actual light, multiply the number of sockets by the lumens of the chosen bulb. Eight sockets equipped with 470-lumen LEDs provide about 3,760 lumens, enough to light a large living room.
Electrical class: I, II or III
A Class I fixture includes accessible metal parts that must be connected to the ground: it therefore requires an installation equipped with a green and yellow wire. A Class II fixture, indicated by a double-square symbol, operates without a ground thanks to double insulation. Class III concerns extra-low voltage.
In older homes without grounding on lighting points, this line becomes decisive. The subject is covered in detail in our article on replacing an old light fixture.
IP rating: two digits, two protections
The first digit indicates protection against solid objects, the second against water. An IP20 rating, common for an indoor decorative fixture, does not protect against water splashes. An IP44 rating resists splashes and becomes necessary in the volumes of a bathroom or under an open outdoor shelter.
Our blown glass fixtures are designed for dry indoor use: they are suitable for a closed conservatory, but not for an open terrace or the immediate vicinity of a shower. For damp or sheltered rooms, refer to our article on conservatory lighting.
Lumens, Kelvin and CRI: light quality
Lumens measure the quantity of light, watts the consumption: you should look at the former. Kelvin gives the color temperature, 2,700 K for warm living room light, 3,000 K for a kitchen, and higher for an office. The Color Rendering Index, or CRI, indicates the fidelity of the colors produced: aim for 90 or more, especially with colored glass.
These three values often depend on the bulb you choose, not the fixture itself. The details are in our article on bulbs, Kelvin and dimmers.
Dimmer compatibility and glass type
The term "dimmable" or "dimmer compatible" concerns either the fixture with integrated LED or the bulb to be installed. Some models include built-in dimming, such as this textured glass and brushed brass pendant chandelier.
Finally, the nature of the glass—opaline, textured, fluted, or transparent—determines glare: opaline glass masks the light source, while transparent glass leaves it visible. This line, often described in words rather than data, counts as much as the numbers. A model like this textured glass and gold metal LED wall lamp combines both pieces of information.
The five-point check before ordering
Diameter compared to your room dimensions. Total height compared to your ceiling, keeping 2.10 m of clearance. Weight compared to what your ceiling can support. The base, so you can buy the bulbs. And the electrical class, if your installation does not have a ground. These five lines appear on every sheet for our blown glass chandeliers and our wall lamps; if you have doubts about a model, our article on the price of a blown glass chandelier also explains what distinguishes two seemingly similar models.