Service
Frequently asked questions
Answers on ordering, delivery and lighting technology. If something is missing, reach us on +49 241 99001621 or at sales@wsulights.com.
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01 Ordering
Purchase, terms, account
Are there terms for business customers?
Yes. Electrical contractors, planning offices and resellers get volume and project terms, special sourcing and on-site service. In B2B mode all prices are shown net. More on the page For Business & Trade.
From which quantity do volume prices apply?
Depending on the item, tiers often start at 4 to 10 units and are shown directly on the product. For larger project quantities (typically from 200 units or recurring annual demand) we prepare an individual quote.
How do I apply for a B2B account?
Register as a business customer. We check the business details and usually activate the account within 24 hours. An existing private account is upgraded with the same e-mail address; history and wishlist are kept.
Do you calculate with or without VAT?
The incl. VAT switch at the top of the header controls the display. The default for private customers is gross, for business customers in B2B mode net. The actual calculation in the cart follows your account status.
02 Delivery
Shipping, abroad, returns
How fast do you deliver?
Items of our own WSU Lights brand are usually ready to ship within 24 hours; orders placed before 17:00 leave the same working day. For traded goods the delivery time shown on the item applies.
Do you ship abroad?
Yes, EU-wide as standard, worldwide on request. Orders from other EU countries with a valid VAT ID are invoiced net. Freight costs for non-EU destinations are presented transparently for approval before shipping.
What does shipping cost?
For B2B customers standard shipping within Germany is free from a net order value of 250 €. Bulky goods (floodlights, large high bays) and freight shipments are charged separately; the amount is shown in the cart at the latest.
What happens with a return?
Within 30 days you can return unused goods in their original packaging. Project and custom-made items are excluded from withdrawal; we point that out before order confirmation.
03 Planning
Photometric data, samples, consulting
Do I get photometric data (IES / LDT) for planning?
For every luminaire relevant to planning we provide IES and LDT files for DIALux and Relux. The download sits on the product and works without an account or order.
Can I order samples in advance?
For projects we provide samples so you can check colour, glare control and build quality before the series order. Request via sales@wsulights.com; feedback usually within 24 hours.
Do you take on the complete lighting design?
Yes. We calculate your area in DIALux to EN 12464-1, select the right luminaire and propose quantity and spacing. This is free even without a subsequent order.
Do you also advise on retrofits of other manufacturers?
Yes. For retrofits the existing installation is the starting point anyway. We tell you what has to be replaced and what can stay, and calculate the payback from the energy savings.
04 Lighting technology
Colour temperature & colour quality
What does Kelvin (K) mean?
Kelvin (K) is the unit of colour temperature. The value describes how warm or cool the light appears. Low values around 2700 to 3000 K look warm white (yellowish, for hospitality, living areas, hotels). 4000 K is neutral white and the standard for offices, retail, practices and education. From 5000 K the light becomes daylight white, used in industry, production and security areas.
4000K neutral white
Standard for offices, retail, practices and education. Good balance of warmth and clarity.
Which colour temperature suits which application?
Rule of thumb: the more concentrated the work, the more neutral or cooler the light. Living areas (homes, restaurants) get 2700 to 3000 K, offices and sales floors 4000 K, technical environments and outdoor lighting 5000 to 6500 K. Within one building keep one colour temperature consistent, otherwise adjacent rooms look restless.
What does the CRI value (Ra) tell me?
The CRI (Color Rendering Index, stated as Ra in Germany) measures how naturally colours are rendered under a light source. Sunlight = 100. From Ra ≥ 80 rendering is sufficient for offices, retail and industry. For textile retail, photo studios, practices and museums we recommend Ra ≥ 90. You will not find values below 80 in our range.
What is UGR and when does it matter?
UGR (Unified Glare Rating) describes the psychological glare of a luminaire. For screen workplaces DIN EN 12464-1 requires UGR < 19. General rooms without screen work need UGR < 22 to 25, warehouses UGR < 28. UGR is always calculated for a specific room and is not a property of the luminaire alone; we provide the manufacturer's figure as a reference.
05 Lighting technology
Output, lumen, efficiency
What is the difference between watts and lumens?
Watts (W) state the power consumption, lumens (lm) the emitted luminous flux. With LED the two decouple: a 36 W LED now produces 4000 to 5000 lm, an old 60 W incandescent bulb only reached about 700 lm. Comparing by watts is therefore no longer meaningful for LED; lumens and colour temperature decide the choice.
What does lm/W (luminous efficacy) mean?
Luminous efficacy (lumens per watt) is the efficiency figure of a luminaire. Current LED panels reach 100 to 130 lm/W, high bays and tubes sometimes 150 lm/W and more. The higher the value, the less power for the same light. For retrofits lm/W is the decisive figure for the payback calculation.
How do I calculate how many luminaires I need?
As a rough estimate: required illuminance (lux) × area (m²) ÷ lumens per luminaire × loss and reflection factor (typically 1.3 to 1.7). For a reliable design to DIN EN 12464-1 we calculate your area in DIALux free of charge. From one sample room the rest can usually be extrapolated.
Which energy class do your luminaires have?
The new EU energy class (2021) ranges from A to G and is shown as a label on every single item. Most of our range is currently in the C to E range; some highly efficient tubes reach B. You will find the EPREL registration number in the data sheet.
06 Lighting technology
Design, protection & dimming
What does the IP rating mean?
IP stands for "Ingress Protection" and describes protection against solids and water with two digits. The common levels:
- IP20 touch protection, no water protection. Dry interiors.
- IP44 splash water. Bathrooms, sheltered outdoor areas.
- IP54 dust protection and splash water. Damp rooms.
- IP65 dust-tight and water jets. Halls, wash rooms.
- IP66 powerful water jets. Outdoor installations, industrial washing.
What is the difference between back-lit and edge-lit panels?
Back-lit panels have the LEDs directly behind the diffuser, which gives higher efficacy and usually a better UGR value. Edge-lit panels guide the light from LEDs at the edge through a light guide plate, giving a slimmer build (often only 9 to 12 mm) but slightly lower efficiency. For screen workplaces with UGR requirements back-lit is the standard today.
Do I need an external driver?
It depends on the luminaire. Panels, high bays and floodlights usually have the driver integrated. LED modules, track systems, ceiling sails and continuous-row systems need an external driver, whose type depends on power and dimming requirement. It is stated explicitly on each product.
What does "dimmable" mean and which protocols exist?
A dimmable luminaire can be adjusted continuously in brightness. Common protocols: phase cut (TRIAC) for simple residential installations, 1–10 V as the analogue B2B standard, DALI as a digital bus system for entire installations (addressable, groupable). The supported protocol is stated on the product. Check compatibility with your controls, otherwise the luminaire flickers or only dims down to 20 %.
07 Warranty
Warranty, genuine products, lifetime
How long is the warranty?
Most of the range comes with a 5-year warranty. For some industrial series (high bays, floodlights) 7 or 10 years are possible; this is stated on the product. Warranty handling runs directly through us, without a detour via the manufacturer.
Are these genuine branded products?
Yes, we only sell genuine branded products sourced directly from the manufacturer or an authorised distributor. No no-name goods, no grey imports. Data sheet, EPREL number and manufacturer warranty are available for every series.
How long does an LED luminaire last?
Current branded LEDs reach 50,000 to 100,000 hours at L70/B10 (after this time 90 % of the luminaires still have at least 70 % of their original luminous flux). At 12 h of operation per day that is about 11 to 22 years. The value is stated on the product.
What happens at the end of life?
Used LED luminaires are electronic waste and belong in separate collection, not in household waste. For larger retrofits we collect the old luminaires on request and hand them to the manufacturer take-back system (per ElektroG). Business customers without collection can use the municipal collection point.
Contact
Question not answered?
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