Whether you're going on an early morning ski tour or boarding a plane, an insulated mug to keep your coffee hot is an invaluable companion. Here are our favorites.听
The Test
First, I tested how well the following five mugs kept drinks hot. I filled the vessels with 200-degree water, sealed them, left them on my kitchen counter, and waited four hours听before measuring the water temperature. 听

But I also wanted to test thermoregulation in a real-world situation (you know, one where you're drinking from the mug), so I determined how quickly I tend to drink coffee (about a quarter of a cup every five minutes). Then I filled each mug with 200-degree water and set an alarm for five minutes. After the time was up, I poured out a quarter cup of liquid. I repeated this process three times before taking the temperature of the remaining water.
Zojirushi SM-KHE48 16-Ounce Stainless Steel Mug

Temperature Loss After Four Hours: 25 degrees
Temperature Loss After 15-Minute Drinking Test: 7 degrees
Verdict: Thermally, the kicked ass. It performed nearly twice as well as any other mug on this list. This might be thanks in part to its overbuilt lid, which has a button to fling back the top and uncover the spout. The lid also features a locking mechanism to keep it closed in the event of a fall.
For Your Commute: The Zojirushi SM-KHE48AG was the skinniest travel coffee container of the group, which made it unwieldy in the cup holder of my 2000 Toyota Camry.
Stanley 16-Ounce One Hand Vacuum Mug

Temperature Loss After Four Hours:听43 degrees
Temperature Loss After 15-Minute Drinking Test: 13 degrees
Verdict: The took second in the four-hour thermoregulation test. The lid operates by a simple one-finger push system (like the Avex, below), which lets you drink by simply pressing down a button on the front of the lid. It also automatically seals the mug when the button's not depressed.
For Your Commute:听This mug fit perfectly in my cup holder thanks to its robust build. Bonus: The textured retro-looking exterior makes the Stanley the most stylish vessel on this list.
Hydroflask 18-Ounce Insulated Coffee, Tea, and Water Bottle

Temperature Loss After Four Hours:听56 degrees
Temperature Loss After 15-Minute Drinking Test: 12 degrees
Verdict: While the has the least high-tech lid of the bunch, it held its own when it came to temperature regulation. Credit that to Hydroflask's sterling reputation for making double-walled, stainless steel, vacuum-sealed water bottles. The Hydroflask is your best bet if you prefer a simple mug: to use it as a water bottle, all you have to do is change the lid.
For Your Commute:听The Hydroflask is thick (although not as thick as the Stanley) and short, which means it fit nicely in my cup holder.
Avex 20-Ounce Highland Autoseal Stainless听Travel Mug

Temperature Loss After Four Hours:听55 degrees
Temperature Loss After 15-Minute Drinking Test: 12 degrees
Verdict: I've used the as my daily mug since I brought one rafting听down the Grand Canyon in May. I absolutely love the design. I found the lid to work very well, with a single easy-to-use button that kept coffee from spilling when I tossed the mug into a raft.
It has the largest volume of any other mug I tested鈥攇reat for a caffeine addict like me鈥攂ut it's not cumbersome thanks to a slim shape. My only complaint: the interior of the lid is difficult to scrub clean, and I found I had to soak it in soapy water to get coffee residue off it.
For Your Commute:听The Highland is skinny and tall, and it didn't fit in the cup holder well. It was especially top-heavy when full.
Oxo听Stainless Steel LiquiSeal Travel Mug

Temperature Loss After Four Hours:听71 degrees
Temperature Loss After 15-Minute Drinking Test: 18 degrees
Verdict: The didn't keep the liquid nearly as warm as the other mugs on this list. But it's still a pleasure to drink from. The Liquiseal has an inch-wide curved silicone strip between the main body and the lid, which gives drinkers a solid grip on the mug.
The Liquiseal has a robust lid that features three layers of silicone seals to prevent spills and a sturdy button that snaps the spout closed. The lid also has the largest lip to drink from, which meant my nose didn't squish into the top during a long sip.
For Your Commute:听The already wide base of the Liquiseal tapers out to a wider middle, which made it sit the most firmly in my car's cup holder听of all the mugs I tested.听