A beautiful scheme can lose its authority the moment a pendant is hung too low, a bathroom fitting lacks the correct IP rating, or a decorative lamp is asked to provide task lighting. This lighting specification guide for interior designers sets out the decisions that turn a visual concept into a considered, buildable and commercially sound lighting plan.
Lighting should be specified alongside joinery, finishes and furniture, not introduced when the room is nearly complete. The fixture is only one part of the decision. Light quality, beam direction, mounting detail, switching, maintenance and compliance all shape how a space feels and performs.
Start with the room, not the fitting
The most successful decorative lighting has a clear role within the architecture. Before selecting a finish, silhouette or brand, establish what the room needs to do at different times of day. A kitchen may need focused illumination for preparation, soft ambient light for dining and low-level evening light once guests arrive. A bedroom needs a gentler hierarchy, with practical reading light that does not flatten the atmosphere.
Ask where people enter, pause, work, eat and relax. Consider sightlines from adjoining spaces, the amount of daylight and which surfaces will reflect light. Pale plaster, polished stone and glazed tiles can amplify brightness; dark timber, deep paint colours and textured fabrics absorb it. The same fitting can feel crisp in one setting and insufficient in another.
A lighting plan is strongest when it uses layers. Ambient light establishes the room’s general level, task light supports a particular activity, and accent light gives depth to art, materials or architectural details. Decorative fixtures often sit between these categories. A chandelier may provide a focal point and ambient glow, but it rarely replaces the carefully placed task lighting required around a kitchen island or dressing table.
Build a lighting specification with purpose
Every item on a schedule should answer a practical question. What is it lighting? How bright should it be? Where will its light fall? How will it be controlled? These questions prevent the common habit of specifying matching fittings across every room, even where their performance requirements differ.
Start with lumens rather than relying solely on wattage. Wattage describes energy use; lumens describe the useful quantity of light produced. The right output depends on room dimensions, surface finishes, available daylight and the desired mood. A compact cloakroom with dark finishes may require more considered illumination than a larger, pale hallway.
Colour temperature is equally influential. For most refined residential schemes, warm white light between 2700K and 3000K creates a welcoming, flattering result. Around 2700K is especially effective in living rooms, bedrooms and dining spaces, where relaxed ambience matters. Kitchens, utility spaces and home offices may suit 3000K where a slightly cleaner appearance supports concentration and detail. Consistency matters, particularly across open-plan rooms where differing colour temperatures can make finishes appear mismatched.
Colour rendering should not be an afterthought. A high CRI helps fabrics, artwork, timber and skin tones appear more natural. Where the project centres on carefully chosen materials, specify light sources with a CRI of 90 or above where possible. It is a small technical line in a schedule, yet it has a noticeable effect on the finished interior.
Select the right fixture for each layer
Ceiling lights and recessed downlights can establish a practical base level, particularly in circulation spaces, kitchens and bathrooms. Their value is discretion, but a ceiling filled with evenly spaced downlights can make a room feel flat and overly bright. Use them sparingly, place them according to furniture layouts and architectural lines, and avoid casting shadows where work takes place.
Pendant lights are ideal for dining tables, islands, stairwells and bedside arrangements because they bring illumination closer to where it is needed. Their scale must relate to both the furniture below and the volume around them. Over a dining table, a single sculptural pendant can feel purposeful; over a long table, a linear piece or a considered cluster may be more balanced.
Wall lights give rooms a more layered, residential character. They are particularly effective in hallways, beside beds, around mirrors and within living spaces where they can wash a wall with warm, indirect light. Consider the direction of the light carefully. An exposed source can create sparkle, while an opal diffuser gives a calmer glow. Neither is universally better - the choice depends on whether atmosphere, visual drama or precise illumination leads the scheme.
Table lamps and floor lamps bring flexibility and intimacy. They should be treated as part of the electrical plan, with switched sockets positioned for the furniture layout rather than added as an afterthought. In hospitality-inspired residential interiors, portable lighting can also create the low-level pools of light that make an evening setting feel composed rather than uniformly lit.
Dimensions, drop heights and visual weight
A specification needs more than a product name and finish. Record the fitting dimensions, overall drop, ceiling rose or fixing plate size, lamping requirements, weight and any driver location. This is especially important for large-scale chandeliers, multi-pendant arrangements and fittings installed into sloping ceilings or bespoke joinery.
Over a dining table, the lower edge of a pendant is commonly positioned around 75 to 90 centimetres above the tabletop. This is a starting point, not a rule. Raise it where the fixture is visually substantial or where views across the table need to remain open; lower it when a smaller fitting needs more presence. On kitchen islands, account for standing eye level, sightlines to the hob and the practical need to see the worktop clearly.
For wall lights, centre height is often around 150 to 170 centimetres from finished floor level, but furniture, artwork and ceiling proportions should guide the final position. Bedside wall lights need to work from a seated position, while mirror lights require careful coordination with the basin, mirror dimensions and the user’s eye line.
Visual weight matters as much as physical size. A fine smoked-glass pendant may disappear in a double-height space, while a dense metal fitting can dominate a compact room. Use scaled drawings, elevation studies and samples where possible. A fitting that looks appropriately proportioned online can read very differently once placed against substantial joinery or richly patterned wallcovering.
Bathroom, outdoor and safety considerations
Technical suitability is essential wherever water, weather or heat are involved. In bathrooms, specify fittings with the correct IP rating for their zone. The closer a fitting is to a bath or shower, the greater the protection required. Decorative choices should follow this requirement, never override it.
Outdoor lighting also needs to be selected for its exposed environment. Consider the IP rating, material durability, coastal conditions, mounting surface and access for future maintenance. Powder-coated finishes, treated metals and suitable glass can all perform well, but no exterior fitting is entirely maintenance-free. A sheltered entrance presents a very different condition from an open garden wall facing prevailing weather.
Always confirm whether a fitting requires an electrician, a separate driver, a transformer or a particular dimming system. If the project includes integrated LED, record the expected lifespan, driver access and replacement route. A concealed driver that cannot be reached without damaging joinery is an expensive detail to resolve later.
Controls create the atmosphere
Good lighting is not simply bright enough. It is controllable enough. Divide a room into useful circuits so ambient, decorative and task lighting can be adjusted independently. In an open-plan kitchen-living space, pendants, under-cabinet lighting, wall lights and general ceiling lighting should rarely all operate from one switch.
Dimming adds flexibility, but compatibility must be checked between the luminaire, light source and dimmer type. Do not assume that a dimmable LED lamp will work perfectly with every existing dimmer. Flicker, limited dimming range and audible buzz can undermine an otherwise premium installation. Specify the intended control method early, particularly where smart home systems or scene setting are part of the brief.
For bedrooms and guest spaces, provide convenient control at the entrance and beside the bed. In hallways and staircases, two-way switching improves daily use. These quiet details make an interior feel resolved long after the first impression of the fittings has settled.
Create a schedule that protects the design intent
A professional schedule keeps decisions clear between designer, client, contractor and electrician. Alongside product imagery and finish, include the item reference, quantity, location, dimensions, IP rating where relevant, lamp or integrated LED details, colour temperature, CRI, dimming compatibility, mounting requirements and lead time. Note the desired switching group and any site-specific installation instruction.
It is also wise to distinguish between a product’s decorative finish and its light output. A brass wall light may be central to the visual scheme, yet its shade, diffuser and lamp choice determine whether it delivers useful illumination. Present both aspects so approvals are based on performance as well as appearance.
The final measure of a lighting specification is the experience it creates after dark. When every layer has a purpose, every finish belongs in the room and every control feels intuitive, the interior gains the depth, comfort and quiet confidence that exceptional design deserves.
For trade projects, Designer Lighting Store can support the sourcing process with a curated selection of contemporary and luxury lighting, helping designers bring decorative ambition and practical suitability together. Allow time for samples, client approval and delivery coordination, particularly for statement pieces or multi-room schemes.
Learn how to layer your indoor lighting in our blog post "A Guide to Layering Light".