Laptop overheating or the fan always loud? What is going on and how to fix it

Normal heat versus a problem

Laptops are designed to run warm, and fans speed up when you ask a lot of them — video calls, games, exports, big spreadsheets. The signs that it has gone past normal are below.

• Hot and loud while idle — fans racing with nothing open usually means something is running in the background
• Slows down when warm — processors deliberately throttle to protect themselves, so a hot laptop is also a slow one
• Shuts off by itself — a sudden power-off under load is a thermal safety cut-out, not a random crash
• Too hot to rest on your lap — a base that is uncomfortable to touch during light use is running hotter than it should

Find out what is working it — Windows and Mac

Before blaming the hardware, check whether software is keeping the processor busy. A stuck process, a runaway browser tab or malware can keep a laptop hot all day.

Fixes you can do yourself

Once software is ruled out, airflow is the next thing to check. These are the simple changes that make a real difference.

• Hard, flat surfaces — beds, couches and doonas block the intake vents underneath — a desk, tray or book helps immediately
• Clear the vents — with it switched off, a few short puffs of compressed air across the vents can shift loose dust
• Keep it out of the sun — a laptop on a sunny desk or in a hot car starts the day already overheated
• Lift the back — a simple stand or cooling pad gives the underside room to breathe; it helps a little, not a lot

When it needs opening up

On a laptop a few years old, the usual cause of constant heat is inside: a fan clogged with years of dust, or the thermal paste between the processor and its heatsink dried out so heat no longer transfers properly. Both are bench jobs — the laptop has to be opened, the cooling cleaned and the paste replaced — and they often make an older machine noticeably quieter and faster. A fan that grinds, rattles or clicks is wearing out and is a straightforward part replacement.

Heat warning signs to take seriously

Some heat-related symptoms are a reason to stop using the laptop rather than keep troubleshooting.

• A bulging case or lifting trackpad — a swelling battery — stop using and charging it, and keep it away from heat; see the battery guide
• Burning or chemical smell — switch it off and unplug it straight away
• Repeated shut-downs — regular thermal cut-outs stress the board and can damage it over time

See also: Laptop battery dying or swelling? · Why is my computer so slow?