What is the purpose of the heat lamp in the bathroom?
 

Ever since I first discovered the heat lamp in the ceiling of a hotel bathroom when I was a child, I was fascinated by this oddity. And thirty years later, I still fail to see any purpose for these things. The most plausible explanation I can envision is that this is some poor substitute for a sauna. Although I can't imagine any self-respecting Finn on holiday, no matter how desperate for a sauna, sitting forlornly on the closed lid of a toilet under a red light bulb.

Clearly this "amenity" has fallen out of favor, as I don't see them in hotels built after the early 1990s, and usually only in those older properties that haven't been renovated for decades.

Can someone please provide some historical background on the mysterious hot light bulb?

I believe it's a quick warm-up without a heat fan blowing hot air
It always has looked sinister to me - red, bright, hot
And the lovely accompanying ticking of the timer switch

I have one in my bathroom (built post-1990). I believe the idea is to help dry the moisture on the person and elsewhere in the room when a person has finished their bath/shower.

As a self-respecting Finn, I thank you for this amusing mental image :D

Surely as a simple, economic to install (not sure about to run) heat source that only needs to be on for the time someone is in the room?

If the hotel room is chilly, the heat lamp is welcome when stepping out of a warm shower into the colder air.

It is used by hotel security for hotel room interrogations... just ask DSK.:D

Interesting thread... I used to wonder what on earth those lamps were for!

But now that you mention it, it has been ages since I last had a hotel room that had one in the bathroom (or maybe more accurately, since I noticed the heat lamp...). I can't recall seeing any in the past few years.

The warmer the air in the bathroom the more moisture the air can hold which means less condensation of the walls and mirror.

Yup. I've used them a couple of times.

Their primary function is to heat surfaces, such as floor. Specific heat of air is so low that little heat is need to heat air. In other words, air cannot store much heat due to is low specific heat. The heat lamp heats surfaces, which help keep the air at a higher temp. If surfaces were cold, hot air would lose its heat rapidly and get cold.
It's tru that warmer air can hold more moisture, but that alone is not enough to reduce condensation. Moisture in the air would still condense on cold surfaces, not so easily on warmer services, other things being equal. But, it's not just the air temp and the temperature of surfaces that determine condensation. When you take a shower, condensation WILL occur, regardless of temperatures, as RH is close to 100%. Slightly higher temperatures can delay onset of condensation. Excess moisture in the air will condense even at high temperatures, and more will condense and at faster rate when the lamp is turned off and surfaces and air begin to cool. Since specific heat of air is low, air does not pl;ay dominant role in heat exchanges.

I haven't seen those heat lamps in places other than older hotels. If you are looking for something warm after a shower then consider a heated towel rack. Otherwise just open the furnaace vent a bit more.

I really like the effect of a heat lamp vs. a towel rack, underfloor heating or a heater fan. I'm going to look around and see if anyone is marketing things that are not circa-1980s in style and if I come up with anything I'll report back.

I don't like to step on cold surfaces bare feet. Gives me chill-blains. The air is comfortably warm just after a leisurely shower, provided the bathroom is not huge. I like heated floor.

They are still available for installation.

They usually take less power than a heater and a fan (two 250 watt bulbs instead of a 1,200 watt heating coil).

The purpose, get this, is to heat you up. Infrared heats surfaces (think grill warming lights), so that when it's on and you step out of the shower, it warms your body, it warms the floor, etc.

In many locations it's a direct replacement for the ceiling fixture, where other fan driven heaters may not be.

Many hotels have replaced it with a flood light bulb or a regular bulb, which will do nothing to heat you up.

If you've ever backed into a heated towel rack when naked and dripping wet, you'd appreciate a heat lamp even more :D