Heat is one of the biggest factors manufacturers must account for when designing a computer. As processors have evolved, added more cores and become more powerful, the amount of heat generated by them has increased. In addition to the CPU, graphics processing units (GPU) have grown in power almost exponentially. As a result, in many modern computers, GPUs can put off as much or more heat than the CPU.

Laptops have few options in terms of naturally cooling themselves. Once you add memory, a hard drive, ports, keyboards and an optical drive, there isn’t much room left for fans or heat sinks. To make matters worse, the components are crammed into a tight space where there’s very little airflow. Power is also a limitation unique to laptops.

These limitations have real-world implications, especially for heavy users. Some laptops with high-end chips have been shown to perform worse under a heavy load than models using less powerful chips due to the high-end CPU slowing down, or throttling, to reduce heat. If you use a laptop, and are worried about excess heat, a laptop cooling pad may be an option to help keep your computer cool.

The biggest factor to consider when looking at a laptop cooling pad is how you use your computer. If you mainly use your laptop for email, web browsing and working with documents, there’s a good chance you don’t need a heavy-duty option. If you use your laptop for graphics, video or gaming, you may need to look for a more robust model.

Another thing to consider when purchasing a cooling pad is the climate and temperature where you live. If you live in a warmer climate or don’t use air conditioning, you’ll need a more powerful cooling pad than if you live in a colder climate or run your air conditioning all the time.

Portability may be a concern to some users. While some cooling pads are designed to be used exclusively on a desk or similar flat surface, others are designed to be taken with you and can even be used on your lap.

Noise level should factor into your decision when shopping for a cooling pad. Many laptop fans can be relatively loud by themselves, so you should try to find a cooling pad that has silent fans.

Look for a model that has the option to use an external power source. Almost all cooling pads rely on power from one of your computer’s USB ports. Many units also include support for an external power source, giving you additional flexibility.

Because cooling pads often use one of your USB ports, some pads come with an integrated USB hub. If you’re already USB-poor, this is a good option to expand your usable ports.

Many cooling pads come with feet or some way to change the viewing angle. Compared to a desktop computer, laptops have never been known for good ergonomics. A desktop separates the computer’s components so each one can be placed at the optimal position and angle, as opposed to a laptop where you have a single focal point. If you spend hours a day using your laptop, choose a cooling pad that offers multiple viewing angles to help improve ergonomics and alleviate neck strain.

Cooling pads measure the amount of air pushed by the fans in cubic feet per minute (CFM). For best results, try to find a model with a high CFM rating. The more air its fans push, the more heat is transferred and the more it will cool your laptop.

Look for a cooling pad that has multiple ventilation openings and airflow channels. This will provide more flexibility if you want to use your laptop in an environment where one or more channels may be blocked, such as on the couch or laying in bed with blankets.

Some high-end pads include a display that gives you control over the fans. You can put them in automatic, or lock them on high or maximum cooling. Some models also include temperature sensors to help you pinpoint where your laptop is the hottest.

Inexpensive: Entry-level models cost $20 to $25 and include one or two fans.

Mid-range: Mid-range models cost $25 to $35 and will often include additional fans, as well as upgraded materials to make the pad more comfortable to use.

Expensive: High-end units will range from $35 to $100 or more. These units have multiple fans, USB hubs, multiple viewing angles and premium materials. These units are ideal for gamers and heavy users who need the most cooling and options available.

• Although multiple fans can mean more airflow, that’s not always the case. In some cases, a single large fan may provide more airflow than multiple smaller fans. When in doubt, check the CFM rating to see what models provides the most airflow.

• While rubber feet that add additional clearance are good if you plan on using a laptop cooler on your desk or flat surface, they can be uncomfortable while using it on your lap. If that’s the case, try finding a model with collapsible feet or a model without feet.

• Some cooling pads have fastening methods to keep your laptop secure. This is a useful feature if you use your pad on-the-go.

• Many laptops get uncomfortably warm to the touch. In addition to keeping your laptop cool, a cooling pad is a good option to help keep you comfortable while using it.

If your cooling needs are minimal, the TopMate TM-3 12-15.6" Laptop Cooling Pad is an excellent value. It includes five fans: one large central fan and four smaller satellite fans. It also includes an LCD screen and five height settings.

The Targus Chill Hub and Chill Mat is aimed at more demanding users. It includes a four-port USB hub, fits up to 17-inch laptops and is designed to be equally usable on your lap or desk.

Q. How much will a cooling pad drain my computer’s battery?
A. That depends largely on the individual model and the features it has. For best results, try to buy a cooling pad that allows you to control the fans so you can turn them off during light use.

Q. Will the cooling pad turn off when my computer is asleep?
A. Some models will. If one doesn’t, and it doesn’t have an off switch, simply unplug it from the computer’s USB port to turn it off.

Q. How much will a laptop cooling pad help?
A. Much of that depends on your laptop and the cooling pad. Some users report a few degrees difference, while others see temperatures as much as 30 degrees cooler.

Q. How much will a few degrees help?
A. Every little bit helps. Because of the nature of laptop design, the cooler you can make them the better. The hotter a laptop runs, the more its internal fans have to work and the shorter its lifespan will be.