What does a bathroom heat lamp (4× bulbs) cost to run?

Those cluster bathroom heat lamps, usually four bulbs in a ceiling fitting and often combined with an extractor fan, pull a serious amount of power. At 275W per infrared bulb, all four running together come to 1,100W, and with fancier units it can be up to around 1,375W. That is a lot of wattage aimed at one small room.

They feel efficient because the warmth is instant and aimed straight at you rather than at the whole room. That directness is genuinely their strength, but it hides how much power is being drawn, because the heat arrives so quickly that people assume it must be modest.

They are meant for short bursts. A few minutes while you shower and dry off, not continuous heating. Used that way, for the handful of minutes it takes to get warm and dressed, they cost very little over a year despite the big wattage, because the run time is so short.

The trouble comes from leaving them running. At over a kilowatt, a heat lamp cluster left on for an hour is drawing like a small heater, and in the combined units the problem is worse, because people forget that the fan and the lamps share a switch and leave the lot going long after they have left the bathroom.

The simplest fixes are habit and hardware. Switch the lamps off as you leave, or fit a timer switch so they cannot be left running by accident, the same trick that tames a heated towel rail. A short run is cheap, an all-day run is not.

There is also a quieter saving in how many bulbs you use. Many models let you run one or two bulbs instead of all four, which is plenty for a quick warm-up and roughly halves the draw. To see it in dollars, put the total wattage and the few minutes a day you really use it into the calculator at your own rate, then try it again with half the bulbs or double the minutes, and the pattern is clear.