A Night Light for an Old Cat: 2 Lux, 3 Spots, 6 Meters

A 2 lux light, 3 plug-in units and a 6 m route solve one specific problem: an old cat that cannot read the floor after dark. It is not a treatment for night yowling, and it does nothing for a cat that is loud because of pain, thyroid disease or high blood pressure. It is the cheapest change on the list, it takes about 20 minutes to install, and it needs 4 weeks before you can judge it.

Why 2 lux and not 20

2 lux is roughly the brightness of one candle at 1 m, or a landing-strip marker. That is enough to show the lip of a step and the rim of a litter tray, and dim enough that the pupil stays wide. Plug-in hallway night lights are usually 15 to 30 lux; at that level the pupil narrows and the far corner of the same room gets harder to read, not easier. Cats lose contrast sensitivity before they lose sharpness, so what helps is a pool of light on the floor, not light washing the ceiling. Check with a phone lux meter at floor level, 30 cm out from the lamp, and aim for 2 to 3 lux; move the unit rather than buy a brighter one. On a matte floor 2 lux lights a pool about 1.5 m across; on gloss tile the same light throws a glare line that reads as a wet patch, which is why a 60 by 90 cm rug under the route is often the second purchase.

3 positions on 1 route

Walk the night route yourself and measure it. A common senior-cat route is 6 m: 2 m from the bed to the doorway, 2 m from the doorway to the water bowl, 2 m from the bowl to the tray. Put 1 light at each turn, 20 cm above the floor, angled down, and 30 cm to one side of the walking line so the cat is never looking into the source. Never light the middle of a room. Light the decision points: the threshold, the step, the tray edge. If the route crosses a room wider than 3 m with no furniture, add a 4th unit or reroute the cat with a 40 cm stool, because a dark gap of 3 m is where most old cats stop and call. The table lists 5 candidate spots for the 3 units; keep the ones that sit on the cat's real 6 m route and drop the rest.

Position	Height above floor	Offset from route	Target lux	On at
Beside the bed	20 cm	30 cm	2	18:00
Doorway turn	20 cm	30 cm	2	18:00
Water bowl	15 cm	40 cm	3	18:00
Tray edge	15 cm	30 cm	3	18:00
Hall midpoint	20 cm	50 cm	2	18:00

12 hours on, dusk to dawn

On at 18:00 and off at 06:00 gives 12 hours and covers the 2 hours of dusk when most night waking begins. In winter shift to 16:30 and 07:00. Use a plug-in timer rather than a switch, because a schedule that depends on somebody being awake fails on exactly the nights it is needed. Three units at 0.5 W each draw 1.5 W, which is about 0.5 kWh a month, under a dollar in most places. Check the timer once a month: a 30-minute drift is harmless, a unit switched off for 3 nights is not, because the cat relearns the dark faster than it relearns the light.

2700 K, and nothing at face height

Choose 2700 K to 3000 K warm white. A 6500 K cool white lamp carries 2 to 3 times more blue, and blue light at night delays sleep onset in cats as it does in people. Keep every unit below 25 cm so the beam lands on the floor instead of the cat's eyes, and keep the level under 6 lux anywhere the cat sleeps. If the bed is in a lit room, leave a 1 m dark band between the last light and the bed edge.

The 4-week adaptation

Week 1: lights on the timer, nothing else changed, note the time of the first waking each night. Week 2: add a 30 cm non-slip mat at each turn; most night misses are slips rather than confusion. Week 3: if the log shows less drinking after dark, move the water bowl to the lit side of the room. Week 4: count the nights out of 7 with no waking before 05:00. Five or more is a result worth keeping; 2 or fewer means light is not the lever, and the next step is a vet visit, not a brighter lamp. Between week 2 and week 4, also note how long the cat takes to cross the 6 m route: 40 seconds at week 1 and 20 seconds at week 4 is the shape of a cat that has stopped guessing.

What light cannot fix

Persistent night yowling has 5 common causes and only 1 is vision. If the cat is losing weight, drinking more, or the noise started less than 2 weeks ago, the light will not help: kidney disease, an overactive thyroid and high blood pressure all present this way in cats over 12. Weigh monthly and write the number down, because 200 g lost in 30 days is easy to miss by hand. If the cat has stopped jumping onto a 40 cm chair, the problem is joints, not light, and a floor pool at 2 lux will not change the score. A cat that walks the route fine at 2 lux but still calls at 03:00 is telling you the problem is not the floor.

Set it up in 5 steps

Measure the route with a tape: bed to bowl to tray, in meters, at night.
Mark the 3 turns with tape on the skirting board before buying anything.
Buy 3 units rated 2 to 3 lux at 1 m, or 3 dimmable units and turn them down.
Set one timer for 18:00 to 06:00 and plug all 3 units into it.
Log the first waking time for 28 nights, then decide on week 4.

If the noise continues after 4 weeks, work through the 5 causes in old cat yowling at night and take a monthly weight trend to the appointment, as described in weighing a senior cat monthly. Power and timer cost is small enough to ignore, but the full monthly care budget is worth pricing in the cost calculator.

Frequently asked

How bright should a night light be for an old cat?

About 2 to 3 lux at floor level, measured with a phone meter 30 cm out from the lamp. That is one candle at 1 m. Standard hallway night lights at 15 to 30 lux narrow the pupil and make the far corner of the room harder to read.

Where exactly do the lights go?

At the turns of the route the cat already walks, roughly 3 units across 6 m, each 20 cm above the floor, angled down, and 30 cm off the walking line so the cat never looks into the source. Light the thresholds and the tray edge, not the middle of the room.

How long before I know whether it worked?

Four weeks. Log the first waking time each night, then count the nights out of 7 with no waking before 05:00. Five or more is a result worth keeping; 2 or fewer means the light is not the lever and the cat needs a vet visit.