The Merrell Thermo Chill Mid WP is a medium-high winter boot that is very lightweight and super comfortable right out of the box. They are also one of the most affordable winter hiking boot options that you will find. We loved how easy they are to use for a lace-up model, and also think that the traction is sticky on a variety of surfaces. However, we also had some complaints, most notably that one of our boots leaked slightly during our waterproof testing, and that they simply weren't very warm compared to many competitors. If you want a comfortable, easy winter hiker that is also affordable, these are a great choice. But if you expect performance in arctic conditions or to be able to tromp through swampy or slushy wetness with impunity, another choice may work out better.
Merrell Thermo Chill Mid WP Review
Compare prices at 2 resellers Pros: Very light, affordable, easy to lace, comfortable
Cons: Not 100% waterproof, not super warm
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Our Analysis and Test Results
A few things were apparent the first time that we put the Merrell Thermo Chill WP on straight out of the box — they are very comfortable, and very light. These two attributes, combined with the lower height of the ankle cuff (only 8"), made for a great first impression. There was no need for any break-in period, and despite their size, these boots felt to us like a larger and well-insulated hiking shoe.
It was only after we performed our comparative side-by-side tests designed to see how boots hold up in the most difficult conditions that we discovered that these boots are better fit for mellow winters as opposed to harsh ones. They were among the least warm that we tested, and one of the boots leaked a bit in our intensive waterproof test. These results bumped them down our rankings a bit, but were still not egregious, especially considering their economical price point. Simply put, we don't think they will hold up well for a winter in a place like Minneapolis, but think they may do just fine in a warmer, milder winter climate such as Denver.
These boots are insulated with 200g of what Merrell describes as their M Select WARM low bulk insulation. We felt that this insulation wasn't exactly low bulk, as these boots are well padded on the inside, and nor was it overly warm. 200g is not generally nearly as warm as the 400g insulation used in some other boots, and this proved to be the case in our comparative ice bath test, where these scored among the lowest. They lost 20.9 degrees over the course of 12 minutes, finishing with a low 42.1F interior temperature. These findings were backed up in testing where we wore the boots on our feet, as they felt significantly colder, and our feet felt chilled much faster than many other pairs. Simply put, these boots are decently insulated for mild cold, but not warm enough for severe cold.
This boot incorporates Merrell's M Select DRY technology, which they claim is an impenetrable waterproof layer that also allows moisture to escape. We aren't sure about the exact dynamics of this technology, but our testing found that one of our boots leaked slowly while standing in five inches of water for 10 minutes. While one boot was totally dry, the other ended with a noticeable amount of water in the bottom. Despite our best efforts, we couldn't discern the point of failure, but we believe it to be the seam between the lower rubber bathtub and the leather upper. Regardless, once inside, the water trickled down to pool in the bottom underneath the insole. This result, combined with the relatively low flood height of 5.75 inches above the ground before the boots would be overtopped, resulted in one of the lowest scores for this metric.
We will admit that our testing was extreme, and that using these boots in average winter conditions, rather than by standing in a deep puddle, would likely result in totally dry feet. They also have a d-ring sewn to the front of the tongue that allows for easy attachment of a gaiter, which will also serve to help keep out water and snow when hiking.
Fit and Comfort
These boots fit true to size and are very comfortable, requiring no break-in time out of the box. We felt that with either a thick or thin sock, the fit of the boot was spot on, with plenty of length and space for wiggling the toes, while also holding the foot securely in place.
The inside of the boot is lined with a fleecy felt fabric that is just as soft as you can imagine. Like all Merrell footwear made recently, the shape of the midsole is such that there is a lot of support under the arch, in a very noticeable way compared to other boots, and we concede that for some people with flat feet this level of support may feel uncomfortable and unwarranted. We also like the "Mid" high ankle cuff, which came up a couple inches less on our calves and shins than similar competition, and thus rubbed us a whole lot less there.
Ease of Use
The Thermo Chill Mid is a lace-up boot, but compared to other lace-ups, it is far easier to very quickly and easily slip on and tie. The laces stay threaded through plastic rings all the way up the top of the foot and the cuff, so do not need to be looped through hooks each time you put them on. Simply slide the foot into the boot, and you can then pull each end of the laces once, and the entire boot will tighten appropriately, there is no need to individually tighten each level moving upwards. One quick pull before tying, and you are good to go. While slip-on designs are still a bit more convenient for those who need to put on boots to go outside repeatedly during the day, these are the most convenient that we have found among the more easily fine-tuned lace-up models.
We also really like the traction offered by this boot. The outsole is made of Merrell's M Select GRIP, a very soft and sticky rubber compound that features deep lugs that are square cut with sharp edges for extra bite. There is an equal amount of negative space to serve as gaps in between the long horizontally oriented lugs, so grip on soft snow or mud is ensured. The softness of the rubber also means that it easily grips to slippery but hard surfaces such as pavement.
These boots have a very affordable retail price in comparison to other winter hiking boots. While they still cost a bit more than our Best Bang for the Buck award winners, which are a Pac-Boot, these are better fits for long days of hiking or snowshoeing. If you want a comfortable lace-up boot at a very reasonable price, we recommend checking these out. However, if you need the warmest and driest boot you can buy for living through harsh winters, then you may not feel like you are getting your money's worth here.
The Merrell Thermo Chill Mid WP are remarkable for how light they are and for how comfortable and inviting they are right out of the box. They're also very affordable, and make for a great boot for places with mild winters, but where protection and traction in the snow are still desired. We wouldn't recommend these for especially cold or damp winter locations, as they scored relatively poorly in our warmth and water resistance testing compared to other choices.
— Andy Wellman