Chill mats can make a laptop PC more comfortable to use, especially in the height of summer. But just how much does their effectiveness get compromised if you take the fan out of the equation?
Last month, I ran a selection of current USB-powered chill mats through their paces, noting that the Logitech N700 which had been my office staple did a good job of cooling, but was too bulky to travel with and not entirely comfortable if you actually rested it on your lap. After that roundup got published, Logitech offered to send me a selection of their more recent models, so I've been putting three of its newer designs through their paces.
The N100 Cooling Pad ($59.95) is for all practical purposes identical to the Belkin Cooling Lounge F5L041 which I tested out last time: it's a similar size (portable enough for flying, though a little bulky), it has the same overall design, and it sells for the same price. It's easy and comfortable to rest on your lap, and a good choice if cooling is your primary aim.
The most obvious alternative for the N700 is the Speaker Lapdesk N550 (around $80), which incorporates a set of speakers but cuts down some of the mammoth bulk found in the N700 and sells for less as a consequence. Despite that, there are two reasons you might prefer the bigger model: it would be an essential for larger notebooks, and it actually incorporates a fan. Yes, the N550 doesn't have any direct cooling technology, though it's solid enough that you certainly won't feel any heat when it sits on your lap. That might help your skin, but it won't do much to stop your PC having a heat overload if (like my main laptop) it's already running at the warm end of the spectrum.
The same approach is taken to near-minimal extremes by the Portable Lapdesk N315 ($49.95), which is essentially just a rectangle of plastic to rest on your lap, with a slide-out area for use with a mouse. The latter might be handy if you are heavily reliant on an external mouse with your laptop, but again there's no actual cooling of your machine. While this is the most portable lapdesk I've seen and well-suited to netbook users, it isn't much smaller than the cheaper Targus Chill Mat, which does incorporate a fan.
One obvious advantage of the no-fans approach is that it cuts down on the noise produced by the chill mat and doesn't drain your battery drawing power for the fan. That could be important if you regularly use your device in a public space such as on a train, if you don't want the audio output from your speakers compromised by noise, or if you're trying to squeeze out as much battery life as possible. However, with a hot-running laptop, you may well find that the lack of noise from the chill mat fan is more than made up for by the whine of your PC itself whenever it starts grunting through more processor-intensive tasks.
There's no such thing as the one perfect chill mat for everyone: what suits you will depend on your working habits, the size and age of your PC, and the degree of thermal resistance in your legs. For myself, anything without a fan really isn't worth the hassle, but I can see how mouse users might like the N315 in particular. What works best for you? Tell us in the comments.
Lifehacker Australia editor Angus Kidman is glad his PC doesn't spend much time in the outback. His Road Worrier column, looking at technology and organising tips for travellers, appears each week on Lifehacker.