Does my laptop hate my table?

September 29, 2005 9:24 AM

I have a laptop computer that is used almost exclusively on a glass table. It has had problems with overheating in the past; one the fans has gone out and had to be replaced. Does it make a difference what kind of surface I have the laptop on and is glass a poor choice for a its workspace?
posted by Ber to computers & internet (9 comments total)

From my experience as long as the surface is flat it doesn't matter what type it is. What is more important is where the fans blow. Do they have lots of room, or is there something up near them (a wall, a a lamp, a box of tissues or even a cable)...if they have poor circulation or are blowing back on themselves it wont help.

Most notebooks have rubber nubs on the bottom to allow air to circulate underneath...have you made sure you're aren't missing?
posted by furtive at 9:34 AM on September 29, 2005

It does make a difference, but it's probably not a substantial one. Most laptops are designed to dissipate heat entirely through the top and sides of the unit, because it may be placed on many heat-unfriendly surfaces, such as a sofa or comfy chair.

Make sure your laptop's feet are intact, like furtive suggests, so there's a layer of air that can move under it.

As far as different materials to place it on, you're looking for the coefficient of thermal conductivity. According to this page, here are some examples:

Aluminium 236 W m-1 K-1
Steel ~50 W m-1 K-1
Glass ~1.0 W m-1 K-1
Wood 0.15 W m-1 K-1
Air 0.024 W m-1 K-1

So glass is actually better than wood in this respect, but also considerably worse than metals. (Don't let the low value for air confuse you; that would only apply if the air was unable to move. Air also moves heat via convection--the moving of actual molecules--which solids are unable to do.)

It may help if you let us know which laptop model you have.
posted by trevyn at 9:44 AM on September 29, 2005

Not really. I once melted a laptop battery (circa 1993) by leaving it to charge on a couch. I don't think the glass, IMHO, could matter much. Some laptops just run hot. I think you best bet if you are concerned with heat I have seen these.
posted by Livewire Confusion at 9:45 AM on September 29, 2005

If you want to get an aluminum stand, per trevyn's post, there's the Kool Sink. No fans, but the maker claims that it moves air by convection currents.

Plus it would look wicked scifi when combined with a glass desktop.
posted by nathan_teske at 10:34 AM on September 29, 2005

I use a CoolPad and it definately makes a difference - in addition to swiveling.
posted by jkaczor at 12:09 PM on September 29, 2005

At home, I stick an empty cigarette pack underneath the back edge of my laptop. At work, it's a pack of post-its or a couple of old floppies taped in a stack.
posted by Lyn Never at 1:56 PM on September 29, 2005

I use CD cases, two on each side so there's a channel under the machine, and my laptop is way hot.

(not in a good way)
posted by pompomtom at 4:46 PM on September 29, 2005

I have a G3 Dual USB iBook. It is on all the time. I have it on a wooden desk, but I have the back edge (the screen edge of the base) propped up on phone books so that there is about 3" of space beneath the back edge of the laptop and the desk. The fan almost never comes on, unless I am burning multiple CD's.

If I place the laptop flat on the desktop, the fan comes on within an hour.

Prop it up. You'll be doing your body a service by bringing the screen up higher. I forgot to mention that I use a USB keyboard while at home (which is when the machine is running all the time).

Make sense?

You could get a nifty stand, but I find the phone books work fine. Get the stand if you are sitting in cafés or libraries a lot (for hours at a time) and need to be mobile.
posted by al_fresco at 7:42 AM on September 30, 2005

OK, thanks for the tips. There are small feet under it but they're maybe a quarter inch high. I am going to try a temporary prop underneath and see if it makes any difference. If it does, then I'll look into one of those stands. Thanks folks.
posted by Ber at 11:52 AM on September 30, 2005