Does a MBP generate enough heat to warm a room?

[Robert Peirce]

I have a small office, about 12'x12' that quickly becomes about 3-4°
warmer than the surrounding area when I am working there. There are two
A/C outlets and an overhead fan. There is nothing in the room
generating heat but me and my MBP. Th MBP gets downright hot above the
keyboard near the screen, but I can't imagine that explains everything.

[Martin Τrautmann]

Post by Robert Peirce
I have a small office, about 12'x12' that quickly becomes about 3-4°
warmer than the surrounding area when I am working there. There are two
A/C outlets and an overhead fan. There is nothing in the room
generating heat but me and my MBP. Th MBP gets downright hot above the
keyboard near the screen, but I can't imagine that explains everything.

The power brick is rated at about 40 to 60 Watts. Your MBP could heat
more than that if the charge would not be higher than its power
consumption. In fact it's the opposite way, during operation the device
will still increase the charge.

Thus the real power consumption is significantly lower than the maximum
rating on your charger. If you want the actual numbers, get a
measurement device for your power socket.

It's your body heat which is significantly higher - I guess about 50 W.
What about the light for your office? Maybe even more...

- Martin

[Robert Peirce]

Post by Martin Τrautmann
It's your body heat which is significantly higher - I guess about 50 W.
What about the light for your office? Maybe even more...
- Martin

I was afraid of that. I'm 6'1" and weigh about 187#. Not much I can do
about me. When I entered the office this afternoon it was still 76° vs.
74° in the hall. Now it is 77° and could easily get to 78°.

I replaced my lights with LEDs on the first go-round. They do generate
a little heat but not a lot and it should mostly be near the ceiling.

I've tried moving air through the room. For some reason or another I
can't make this work very well. Even opening the windows with an
outside temperature below 70° doesn't seem to have much impact.

Oh, well. I've been living with this for three years and it isn't
terribly uncomfortable, just annoying. The overhead fan helps a lot.

[Martin Frost me at invalid stanford daht edu]

Post by Martin Τrautmann

Post by Robert Peirce
I have a small office, about 12'x12' that quickly becomes about 3-4°
warmer than the surrounding area when I am working there. There are two
A/C outlets and an overhead fan. There is nothing in the room
generating heat but me and my MBP. Th MBP gets downright hot above the
keyboard near the screen, but I can't imagine that explains everything.

The power brick is rated at about 40 to 60 Watts. Your MBP could heat
more than that if the charge would not be higher than its power
consumption. In fact it's the opposite way, during operation the device
will still increase the charge.
Thus the real power consumption is significantly lower than the maximum
rating on your charger. If you want the actual numbers, get a
measurement device for your power socket.

Post by Robert Peirce
It's your body heat which is significantly higher - I guess about 50 W.
What about the light for your office? Maybe even more...
- Martin

I was afraid of that. I'm 6'1" and weigh about 187#. Not much I can do
about me. When I entered the office this afternoon it was still 76° vs.
74° in the hall. Now it is 77° and could easily get to 78°.
I replaced my lights with LEDs on the first go-round. They do generate
a little heat but not a lot and it should mostly be near the ceiling.
I've tried moving air through the room. For some reason or another I
can't make this work very well. Even opening the windows with an
outside temperature below 70° doesn't seem to have much impact.
Oh, well. I've been living with this for three years and it isn't
terribly uncomfortable, just annoying. The overhead fan helps a lot.

An average person gives off about 100W of heat, same as a 100W bulb.
You're a little bigger than average, so maybe you generage 125W. The
MBP generates heat up to it's power brick's rating, so maybe 50W,
given that you say it gets hot. The LED lights probably are around
10W each, so unless there are lots of them, they won't add much heat
(but turning them off when possible will reduce the heat a little).
(That heat "near the ceiling" does spread to the room.)

Opening the window is certainly useful if it's cooler outside, but
what would help more is to run a fan in the open window to bring in
more cool outside air. That's exactly what I do.

Martin

[Davoud]

Post by Robert Peirce
I've tried moving air through the room. For some reason or another I
can't make this work very well. Even opening the windows with an
outside temperature below 70° doesn't seem to have much impact.
Oh, well. I've been living with this for three years and it isn't
terribly uncomfortable, just annoying. The overhead fan helps a lot.

If you move outside air at 70°F into a room where the temperature is
76°F the room *has* to get cooler. The key idea, however, is moving the
air, not simply opening the window.

[Jolly Roger]

Post by Robert Peirce
I have a small office, about 12'x12' that quickly becomes about 3-4°
warmer than the surrounding area when I am working there. There are two
A/C outlets and an overhead fan. There is nothing in the room
generating heat but me and my MBP. Th MBP gets downright hot above the
keyboard near the screen, but I can't imagine that explains everything.

Yes. Most electronics generate heat. In the absence of some sort of
cooling or air conditioning, a computer in an enclosed space will
naturally increase warmth in the space.

[nospam]

Post by Jolly Roger

Post by Robert Peirce
I have a small office, about 12'x12' that quickly becomes about 3-4°
warmer than the surrounding area when I am working there. There are two
A/C outlets and an overhead fan. There is nothing in the room
generating heat but me and my MBP. Th MBP gets downright hot above the
keyboard near the screen, but I can't imagine that explains everything.

Yes. Most electronics generate heat. In the absence of some sort of
cooling or air conditioning, a computer in an enclosed space will
naturally increase warmth in the space.

a single macbook won't make much of a difference.

[Davoud]

Post by Robert Peirce
I have a small office, about 12'x12' that quickly becomes about 3-4°
warmer than the surrounding area when I am working there. There are two
A/C outlets and an overhead fan. There is nothing in the room
generating heat but me and my MBP. Th MBP gets downright hot above the
keyboard near the screen, but I can't imagine that explains everything.

Layman's understanding: the zeroth Law of Thermodynamics requires that
the MBP heat the room to some extent unless the room is already at a
higher temperature than the MBP produces when operating, in which case
the room will heat the MBP. The MBP would make a discernible
contribution to the ambient temperature in a closed, unventilated, 12'
square room, as would your body heat if it is higher than the room's
ambient temperature (otherwise the room will heat you). Self-contained
cooling systems take for granted that the environment in which the
cooling system operates is cooler than the device being cooled.
Remember that a fan can move air around, but it cannot cool it.
Standing in front of a fan can cool a person to an extent, as it causes
perspiration to evaporate, and evaporation draws heat away from the
surface (one's skin) from which the liquid is evaporating. In a closed,
unventilated room, however, a fan would add heat due to the heat
generated by its motor.

[Doc O'Leary]

For your reference, records indicate that

Post by Robert Peirce
I have a small office, about 12'x12' that quickly becomes about 3-4°
warmer than the surrounding area when I am working there. There are two
A/C outlets and an overhead fan. There is nothing in the room
generating heat but me and my MBP. Th MBP gets downright hot above the
keyboard near the screen, but I can't imagine that explains everything.

While all electronics are going to generate some excess heat, laptops are
intentionally designed to be relatively low on that scale. You are likely
the largest contributor (if there truly isn’t any other heat source, like
incandescent lighting or the Sun streaming in through the windows.

It’s a simple enough experiment to run: at the start of the day just set
up your computer to run some normal software and go out for a cup of
coffee or a nice walk. Come back in 15-30 minutes and see how much
hotter the office has gotten. Or do the reverse by keeping the Mac off
and just sit at your desk reading the paper or a book for the same amount
of time.