What is the single most important thing about a lamp?

The shade, not the base. An opaque shade directs light down onto what you are doing; a glass or open shade sends it into your eyes and up the wall. Most lamps sold as 'design pieces' have the second kind, which is why they photograph well and read badly in a room.

How bright should a living-room lamp be?

Bright enough to read by at the chair, not bright enough to light the whole room. Around 400–600 lumens at the seat is a workable target. If one lamp lights the entire room evenly, it is a ceiling light wearing a floor lamp's clothes.

Is warm light always better?

For evenings, yes — 2700K or below. For a desk or a task light, 3000K is more comfortable for detail work. What matters most is that all the lamps in one room share a temperature; mixing 2700K and 4000K in the same sightline makes both look wrong.

One Lamp Decides What the Room Is After Dark

At seven in the evening a room either works or it does not, and by eight it is too late to fix. The ceiling light goes on, the room gets brighter, and somehow it also gets worse — flatter, more exposed, more like an office at the end of the day. Nothing in the room has changed. The light has.

This is the cheapest, most reversible improvement available to any home, and almost nobody does it deliberately. People buy a lamp because a corner is dark, put it where the socket is, and live with whatever it does.

Why one lamp beats five ceiling bulbs

A ceiling light comes from above, which is where daylight does not. Daylight arrives low and horizontal in the morning and evening, and only from directly overhead around noon — the hours most people are at work. A bulb in the middle of the ceiling reproduces the one moment of the day nobody is home for.

It also lights everything equally, and equal light is the visual signature of a public building. A room reads as domestic when light is uneven: bright at the chair, dim at the walls, a pool of warmth on one side and shadow on the other. That unevenness is what a single lamp gives you for free.

The practical consequence: turn the ceiling light off in the evening and use lamps only. If the room is then too dark to use, the answer is a second lamp, not the ceiling switch.

Three numbers decide whether a lamp works

Height. A floor lamp's shade should sit at or just below eye level when you are seated — around 100–110cm from the floor for most chairs. Higher, and you are looking into the bulb; lower, and it lights your knees. A table lamp should put its shade at roughly the same height when it stands on the table beside you, which means a 40cm lamp on a 60cm table is usually right and a 60cm lamp is usually wrong.

Shade material. Opaque, always, for anything you will sit beside. Fabric, metal, ceramic — all fine. Glass and open wire shades throw light sideways and upward, which is beautiful in a photograph and useless in a room: the light goes where your eye is, and the page stays dim. If you love a glass-shade lamp, use it as a background light in a corner, never beside a chair.

Colour temperature. 2700K for evenings. Not 3000K, which is fine in a kitchen and slightly clinical in a living room, and never the 4000K that cheap bulbs default to. And keep it consistent: two lamps in one sightline at different temperatures make both look wrong, no matter how good each is alone. Buy the bulbs in one batch and write the number inside the shade.

The one thing worth spending on

Lamps divide into two parts with two different failure modes. The base fails by being ugly or unstable; the shade fails by being translucent. Almost every lamp that reads as expensive and looks cheap in a room has the same problem — a shade that leaks light.

So: spend on the shade if you spend anywhere. A modest ceramic base with a well-made opaque linen shade will look better than a designer base with a paper shade. And when the shade discolours — and it will, linen yellows — replace the shade rather than the lamp. It is a £25 part and it resets the object for another decade.

How to test a lamp before you pay for it

Three tests, all of them free, none of them requiring the shop's permission.

The hand test. Hold your hand 30cm in front of the shade at the height where your head would be. If you can see the shadow of your fingers on your palm, the shade is translucent and the lamp will put light in your eyes. A good opaque shade gives a soft, almost shadowless glow.

The phone test. Turn the lamp on in the shop, then look at the shade through your phone camera. Cameras exaggerate hotspots, which is useful: a shade that looks even to the eye but shows a bright band on screen will show that same band on your wall at night, because the bulb is closer to one part of the shade than the other.

The reach test. Sit in a chair at the height you would sit at home — most shops have one — and check where the switch is. A switch on the cable at 30cm from the floor means bending down in the dark every night. An inline switch at 90cm, or a touch dimmer on the base, is the difference between using the lamp and not.

What it costs to run, and what to do with the old bulbs

A 7W LED at 2700K, on for five hours a night, uses about 13kWh a year. At a typical tariff that is roughly £4. Three lamps in a house is £12. The old 60W incandescent it replaced would have used 110kWh a year each — around £33 per lamp, or £100 for the same three. The bulbs pay for themselves in the first winter and then keep paying.

Two things worth knowing when you replace them.

Buy in one batch, from one brand. Colour temperature is nominal: two "2700K" bulbs from different manufacturers can differ by 200K, and side by side in one room that difference is visible as one lamp looking pink and the other looking green. Buying six at once costs the same per bulb and guarantees they match.

Do not throw the old ones away in the room. Incandescent bulbs contain no mercury, but compact fluorescents do — a broken CFL needs ventilating for fifteen minutes, not vacuuming. Take them to a household waste site. And keep one incandescent bulb in a drawer: it is the only bulb that dims smoothly on an old dimmer circuit, and it is useful for testing whether a flickering lamp is the bulb or the wiring.

What a room looks like when it is lit properly

One light at the chair, one small light in the corner that used to be dark, the ceiling off, and the walls doing less than they did at noon. The room is dimmer and larger at the same time, because the eye stops reading it as a box and starts reading it as a place.

That is the whole trick. Not a lighting scheme, not layers, not a designer. One lamp in the right place, at the right height, with a shade that keeps the light where the work is — and the decision about what the room is after dark is made.