Lighting a room

Lighting affects how a room feels more than colour or furniture, and most homes have the arrangement that developers install rather than one anybody chose.

Why the single ceiling light fails

It lights everything from one direction and one height.

Which flattens the room, produces unflattering downward shadows on faces, leaves corners dark, and provides no variation between activities.

A room lit this way looks smaller and less inviting than the same room with several sources, at no additional structural cost.

The three layers

The framework that professionals use.

Ambient light — the general illumination that lets you move around.

Ceiling fittings, uplighters, or several lamps together.

Task light — directed at what you are doing.

Reading lamps, a light over a work surface, a desk lamp, a mirror light.

Accent light — highlighting something specific.

A picture, a shelf, a plant, an alcove.

A room with all three feels considerably better than a room with only the first, and adding the other two generally means two or three lamps.

Colour temperature

Where a great deal of unpleasant lighting comes from.

Measured in kelvin, with lower numbers warmer and higher numbers cooler.

Around two thousand seven hundred kelvin is warm, resembling traditional incandescent light, and suits living rooms and bedrooms.

Around three thousand to four thousand is neutral, and suits kitchens and bathrooms.

Above five thousand is cool and daylight-like, and in a domestic living space generally reads as clinical.

Consistency within a room matters more than the specific choice, since mixed temperatures look wrong even when nobody can identify why.

Brightness

Now measured in lumens rather than watts, since energy-efficient sources use very different power for the same output.

Rough equivalents worth knowing: an old sixty-watt incandescent bulb produced around eight hundred lumens, and a hundred-watt around sixteen hundred.

Which is the figure to look for when replacing.

More lumens is not better: a living room lit at kitchen levels is uncomfortable, and the useful approach is several moderate sources rather than one bright one.

Colour rendering

An overlooked specification.

The colour rendering index indicates how accurately a light source shows colours, on a scale to a hundred.

Cheap sources may be in the seventies, which makes fabrics, food and skin look wrong.

Ninety and above is noticeably better, and the difference is visible in kitchens, bathrooms and anywhere colour matters.

Dimming

Worth arranging where possible.

The ability to reduce light in the evening changes how a room functions and aligns with the natural decline in light that the body responds to.

The practical caution: not all light sources dim, and those that do require a compatible dimmer.

Incompatible combinations flicker, buzz or fail to dim to a low level, which is the most common complaint after installing dimmers.

Smart bulbs dim without any wiring change, which for a rented property is the practical route.

The practical improvements

In order of effect for the cost.

Add two or three lamps at different heights and turn the ceiling light off.

Replace any cool-white bulbs in living spaces with warm ones.

Add a light on a shelf or behind furniture, which produces the indirect light that makes a room feel larger.

Put lamps on switched sockets or smart plugs, so they are actually used.

Add task lighting where you read, cook or work.

And use lampshades that direct light rather than bare bulbs, which glare.

Outside and circulation

Two areas usually neglected.

Hallways and stairs benefit from light at low level as well as overhead, both for appearance and for safety.

And an outdoor light at an entrance, on a sensor, is a small change with a disproportionate effect on how a house feels to approach.

Colour temperature and rendering

Two numbers on the box that determine how a room feels.

Colour temperature, in kelvin, describes how warm or cool the light appears.

Roughly 2700 kelvin is the warm domestic light most people want in living rooms and bedrooms; 3000 is slightly crisper and suits kitchens and bathrooms; anything above 4000 reads as clinical in a home.

Mixing temperatures within one room looks wrong, and it is worth buying all the bulbs for a room together.

Colour rendering index describes how accurately colours appear under the light.

Above 90 is good, and cheap bulbs with poor rendering are why some rooms make skin, food and fabric look grey regardless of how bright they are.

General information only, not professional advice. Electrical installation is regulated in most jurisdictions — consult a qualified electrician for wiring work.