There is a problem cited throughout these reviews that since the mug warmer is not a hot plate, and doesn't reach higher temperatures, it can only help keep a mug warm. It cannot make hot a cup of coffee or tea from a cold start. I wondered about this, and tried it out, and yes, it is a problem. But there is a simple solution, cost about 10 cents, using a solution from physics and proven on long hikes. I tried it, and it works better than expected here as well. I can take a cup of water from a cold start to being just the right temperature for sipping, not quite steaming, but hot! Here's the physics: there are several types of heat, the most important in this case being radiant heat. Radiant heat is called radiant heat because it travels in rays. In this case, it comes up from the surface of the warmer, and yes, there is some other types of warming going on, but most of what seems to be happening to the liquid is that the radiant heat is traveling through it, and then dissipating into space. The cup loses other forms of heat too, but by just solving the radiant heat loss problem, you will have solved the entire problem of your warmer not being able to warm full cups of coffee or tea, or make cool water warm to start with for dissolving the tea or coffee in it. (I even use loose tea with this solution, and it works fine; it gets hot enough that it does not have to be a mix.) So what do you do to overcome radiant heat loss? A burner would just apply more heat. But if you wanted a hot stove in your office you'd buy a burner, for about 5x the cost of this, and then run the risk of injury in tight quarters. In this case, apply a radiant barrier. A radiant barrier can be fancy or expensive, but you can fashion a very serviceable and even decent looking one with practice out of about a foot of aluminum foil. Anyone who has been camping or tried to travel light while distance hiking knows that you can make a light pot cozy of aluminum foil that serves as a shield against win. The surprising thing is that this simple material we are used to using for wrapping pot roast has the amazing property as applied of cutting your need for fuel dramatically on the way to boiling water. So applied to the mug warmer, fill your mug, put it on, then by folding the aluminum foil a few times to a) stiffen it up, and b) fit around the cup, make a loose fitting wrap that sits just outside the mug, not too tight since you want to re-use it many times. Then apply a paperclip, preferably a small binder clip to joining the foil. Of course you can use other things as well. This way it lifts right off, and can be put right down. Of course, just going around the outside of the mug, the most important area is left open. So fold and refold a second piece of aluminum foil into a stiff square that rests on top of the lip of your mug. Actually this part alone is often sufficient to keep your coffee far hotter than the burner alone, and will work to heat up cool coffee. The additional loose wrap around part just makes it that more efficient. This really worked well for me, to the point I am very pleased, and don't have to run down to the microwave to re-heat my coffee or tea, but can do it from scratch, right on the cup warmer. I like the truly functional aspect of it, that I made it myself for ten cents, and can show a little creativity in sculpting it into something that looks alright, plus it recalls some good hikes . . . But if this is too man cave for you, there are pot cozies you can buy on amazon. Just make sure that they have a radiant barrier in them, or put some foil inside them too, tho no one will see it. That way, you keep recapturing radiant heat, and this is probably 90% of the battle. This way, by turning the radiant heat back on the cup, and back again, again and again, you multiply its effect pretty dramatically. IF this proves helpful, or you think it may, please give it the thumbs up. I'd like to see it rise as a helpful review so it can help solve what so many people have complained of.
