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Merrell Thermo Chill Mid WP Review

An affordable and comfortable winter boot solid enough for milder winters.
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Price:  $110 List | $109.95 at Backcountry
Compare prices at 2 resellers
Pros:  Very light, affordable, easy to lace, comfortable
Cons:  Not 100% waterproof, not super warm
Manufacturer:   Merrell
By Andy Wellman ⋅ Senior Review Editor  ⋅  Nov 26, 2019
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69
OVERALL
SCORE


RANKED
#14 of 14
  • Warmth - 25% 6
  • Water Resistance - 25% 5
  • Fit and Comfort - 25% 8
  • Ease of Use - 15% 8
  • Traction - 10% 9

Our Verdict

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.


Compare to Similar Products

 
Awards  Editors' Choice Award  Best Buy Award Top Pick Award 
Price $109.95 at Backcountry
Compare at 2 sellers
$199.00 at REI
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$109.95 at Backcountry
Compare at 3 sellers
$68.44 at Amazon$70.80 at Amazon
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Pros Very light, affordable, easy to lace, comfortableWarm, completely waterproof, comfortable, good traction, supportiveSupportive, good traction, very warmWarm, comfortable, affordable, great tractionInexpensive, warm, super user-friendly, good traction, made in USA
Cons Not 100% waterproof, not super warmSizing runs a bit small, expensiveMore difficult to pull on and off, relatively complicated lacing system, break-in periodNot completely waterproof, more labor intensive to put on than othersClunky loose fit, not for hiking, leaking seam between upper and lower
Bottom Line An affordable and comfortable winter boot solid enough for milder winters.Oboz combined comfort, warmth, waterproofness, and traction, making the Bridger 10 our new Editor's Choice Award winner.A high quality boot that is a warm and comfortable choice for winter hiking and snowshoeing.A very comfortable boot at the most affordable price.The Greenbay 4 is an incredibly user-friendly and utilitarian winter boot.
Rating Categories Merrell Thermo Chill Mid WP Oboz Bridger 10" Insulated Vasque Snowburban II UltraDry Kamik NationPlus Kamik Greenbay 4
Warmth (25%)
10
0
6
10
0
10
10
0
9
10
0
9
10
0
9
Water Resistance (25%)
10
0
5
10
0
10
10
0
9
10
0
5
10
0
6
Fit And Comfort (25%)
10
0
8
10
0
6
10
0
8
10
0
9
10
0
6
Ease Of Use (15%)
10
0
8
10
0
6
10
0
5
10
0
6
10
0
10
Traction (10%)
10
0
9
10
0
9
10
0
8
10
0
9
10
0
8
Specs Merrell Thermo... Oboz Bridger 10"... Vasque Snowburban... Kamik NationPlus Kamik Greenbay 4
Maximum puddle depth before major leaking 5.75 in 8.5 in 7.25 in 4.5 in 3 in
Appropriate Activity All activities, from chores to hiking All activities, from chores to hiking All activities, from chores to hiking All activities, from chores to hiking Chores, errands
Width Options Regular Regular Regular Regular, Wide version available Regular, Wide version available
Fit Details True to size Runs 1/2 size small True to size True to size Roomy
Measured Shaft Height (from bottom of sole to top of shaft, Size 10) 8 in 10 in 8.5 in 11 in 14 in
Weight (Per Pair, size 11) 2.6 lbs 3.6 lbs 3.4 lbs 3.6 lbs 4.4 lbs
Lining/Insulation 200g M Select Warm 400g 3M Thinsulate synthetic fibers 400g 3M Thinsulate Ultra Insulation Removable 200B 3M Thinsulate 6 mm Thermal Guard
Upper Material Leather, mesh Waterproof nubuck leather 1.8mm Waterproof Leather Waterproof suede and ballistic nylon Waterproof 600D nylon
Toe Box Rubber Rubber Durable rubber toe rand Rubber Rubber
Outsole Merrell Select Grip Winterized Rubber Vasque Nordic Rover outsole with ColdHold Technology SNOWTREAD Synthetic Rubber Prime Rubber
Company-claimed cold-weather rating Not listed Not listed Not listed -40 F -25 F
Animal products used? Yes - Leather Yes - Leather Yes Yes No
Sizes Available 7 - 14 8 - 14 7 - 14 7 - 14 6 - 15

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.

Performance Comparison


The Thermo Chill Mid are a very lightweight boot that are super comfortable to hike in  have a lower ankle cuff than most that we compared them against  and are easy to lace up.
The Thermo Chill Mid are a very lightweight boot that are super comfortable to hike in, have a lower ankle cuff than most that we compared them against, and are easy to lace up.

Warmth


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.

These boots kept our feet warm on this mild day hiking in shallow snow just fine  but our intensive testing revealed that the 200g of insulation used was not up to the task of super frigid temperatures.
These boots kept our feet warm on this mild day hiking in shallow snow just fine, but our intensive testing revealed that the 200g of insulation used was not up to the task of super frigid temperatures.

Water Resistance


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.

Standing in this shallow lake for ten minutes revealed a slow leak in one of our boots  that wasn't from over-topping. We couldn't be exactly certain where it came from  and regardless we still consider these boots pretty water resistant  but not up to the extreme challenge of hanging out under water.
Standing in this shallow lake for ten minutes revealed a slow leak in one of our boots, that wasn't from over-topping. We couldn't be exactly certain where it came from, and regardless we still consider these boots pretty water resistant, but not up to the extreme challenge of hanging out under water.

We suspect that the small and slow trickle leak during our testing took place at either the seam between the black rubber bathtub on the bottom of the upper and the black leather above it  or between the glued seam between the black and grey rubber  although we couldn't be totally certain.
We suspect that the small and slow trickle leak during our testing took place at either the seam between the black rubber bathtub on the bottom of the upper and the black leather above it, or between the glued seam between the black and grey rubber, although we couldn't be totally certain.

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 lining of this boot is rather thick and bulky  which actually does a good job of cradling and cushioning the foot. The material is soft fleece which reminds us of the texture of puppies ears. These comfortable boots require no break in time.
The lining of this boot is rather thick and bulky, which actually does a good job of cradling and cushioning the foot. The material is soft fleece which reminds us of the texture of puppies ears. These comfortable boots require no break in time.

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.

One of the best attributes of this boot is its light weight. In fact  this is the lightest boot in this review  which certainly makes hiking long distances far more pleasant.
One of the best attributes of this boot is its light weight. In fact, this is the lightest boot in this review, which certainly makes hiking long distances far more pleasant.

For a lace up  the Merrell Thermo Chill are among the easiest to use. Simply pull the ends of the laces once  and the whole boot tightens up as desired. This is far easier than boots where you must loop the laces through hooks  but not as easy as slip-on models.
For a lace up, the Merrell Thermo Chill are among the easiest to use. Simply pull the ends of the laces once, and the whole boot tightens up as desired. This is far easier than boots where you must loop the laces through hooks, but not as easy as slip-on models.

Traction


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.

The outsole of this boot features a very aggressive lug pattern that is deep  has sharp cut lugs  and grips very well on pretty much any surface  including soft snow.
The outsole of this boot features a very aggressive lug pattern that is deep, has sharp cut lugs, and grips very well on pretty much any surface, including soft snow.

Value


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.

While they aren't as waterproof or as warm as some of the other competitors  the Merrell Thermo Chill Mid WP are super comfortable and very affordable  making them in ideal choice if you need winter boots only occasionally  or live in a relatively mild winter location.
While they aren't as waterproof or as warm as some of the other competitors, the Merrell Thermo Chill Mid WP are super comfortable and very affordable, making them in ideal choice if you need winter boots only occasionally, or live in a relatively mild winter location.

Conclusion


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.

Tromping through the snowy woods in the Thermo Chill is a pleasant experience  especially if the snow isn't too deep  and it isn't too frigid outside. Basically  we loved it for the mild conditions we had this day.
Tromping through the snowy woods in the Thermo Chill is a pleasant experience, especially if the snow isn't too deep, and it isn't too frigid outside. Basically, we loved it for the mild conditions we had this day.


Andy Wellman