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Why are these doorknobs warm? Answered

Hello world! I have a random issue that has been stumping my class since it began: the doorknob is warm. No other doorknob there is warm. There are a few other knobs in the room and they aren't warm, so I don't think it has to do with the heat difference.

They aren't just a little warm, they are significantly warmer than other doorknobs. I'm in a room full of engineers and none of us have any idea why they're so warm!


Hello buddy

gata brothers.jpg

Has it ever been accessed regularly by a company executive? We have doors in our building that are accessed by the CEO. He hates cold door handles, so some handles are kept warm. I don't know what the warming method is, though.

Does it have any electrical components such as a keypad, or remote locking system?

I think the knob has a different color than other ! The black color absorbs more heat and others absorb less in comparison to black. And may be it faces the window from where the sunlight comes!

What is on the other side of the door with the warmer knobs?
Are all the other knobs on the same side of the room?
What is under the room? is there perhaps a boiler room, plant room or other source of heat that could be rising through the floor & absorbed by the door?
Is the door with the warmer knobs in a south facing wall or corridor?
Are all the knobs made from the same materials?


4 years ago

Is that door used more frequently than others?
Is any electrical equipment assembled (central locking, release buzzer, electric strike, theft protection ...)?

Instead of just FEELING IT... do an investigation. Measure it's temperature with a no-touch digital thermometer. If the surface of the doorknob is SHINY, then the laser type thermometer will not work when looking at a reflective surface. Use a contact thermometer. See if the temperature is constant or is slowly going down. If it is constant, something is acting on it like a hidden wire/heating element or an infra-red light beam is shining on it. If the temperature is going down... down.... down as the hour passes.... that means someone is warming it up with a hair-dryer or something before class starts. Do various experiments like that to figure out what is going on. If nobody is playing a trick... then it might be possible if the door is metal that some electrical wire in the wall has a nail through it or a pinched wire causing the door to be "hot" and the doorframe is "ground" causing heating. MOST likely... in a room of engineers.... someone is a JOKESTER.

Perhaps they are absorbing microwave energy,
or maybe they are radioactive?

Or something similar to what Vyger said.
Does the room on the other side have windows?
Is it possible that sunlight is directly hitting the knob on the other side?
Is it warm at all times of the day?


4 years ago

Because the room on the other side is hot. ------ Basic fire safety, if you believe there is a fire in the building and you reach for the door and the knob is hot, DO NOT OPEN it as the fire is likely in the room on the other side. Find another way out. Metal doorknobs transfer heat.

I can confirm that !
When  we had a fire in our living room years ago as I touched that door
the knob was hot and I got low to open my way to reach the outside hose on the other side.

1. really measure the temperature and make sure it isn't subjective.

2. As MP says take it apart. Analyse.

Well your engineers so bring in some tools and pull it apart. See if there is anything inside the door causing the added heat. Or keep an eye on your teacher and see if he/she is using a torch on it between classes.