Review: SmartWool PhD HyFi Half Zip merino top

Today we are reviewing the SmartWool PhD HyFi Half Zip top. When I heard about SmartWool’s new PhD products for this winter and looked at the HyFi and the SmartLoft jackets, I immediately thought they would be ideal to take climbing. I always climb in merino baselayers but none can cut it for winter. Although temperatures are mild in Spain, a heavy-weight baselayer is not enough in anything but mid-day sun.

How it was tested

The SmartWool PhD HyFi Half Zip was tested mainly bouldering and rock climbing around Tarragona, south of Catalonia. It was also used for skiing, cycling, hiking and around town.

La Riba

Photo credit: Predo L.

SmartWool PhD HyFi Half Zip features

The PhD HyFi Half Zip is composed of two layers. On the outside a nylon fabric gives the top better resistance to abrasion and wind. Inside is a layer of SmartWool’s super fine merino.

It has an outside chest pocket with an opening for a headphone cable and thumbs holes on the sleeves. In size S the SmartWool PhD HyFi Half Zip weights 468g / 16.5oz. This is about 100g heavier than the average Polartec Power Stretch mid layer, which have a similar construction.

Resistance of the outer fabric

The nylon layer proved very resistant to rock abrasion. While working on some bouldering problems it is not uncommon to brush with the rock but the HyFi Half Zip handled it well with still no snags to be found.

The outer fabric also gives the jacket some wind resistance but don’t expect it to replace your softshell. Anything more than a gentle breeze will be felt, depending on what you have layered under it.

HyFi Half Zip side

Photo credit: Predo L.

Comfort and looks

The semi-form fit of the PhD Hyfi Half Zip turned out to be perfect. Enough room to land the hardest moves but still easy to layer under a warmer jacket. Also the size S in this case is spot on unlike other shirts I tried before from SmartWool (see my review of the Teller Tech Zip).

SmartWool PhD HyFi Half Zip

It is perfect as a second layer, worn above a baselayer. It provides warmth comparable to a good quality fleece but with the added perks of merino wool, namely odour resistance and moisture and heat management. Plus the half zip allows for great ventilation control. The sleeve are just the right length and the thumb holes very handy when you stop moving and put on an extra jacket while spotting your mates.

Photo credit: Predo L.

Photo credit: Predo L.

The combo long sleeve merino baselayer, SmartWool PhD HyFi Half Zip and a softshell was perfect for all day snowboarding in sunny weather. Never got cold on the lift nor too hot going down. Around town I also found the HyFi Half Zip to be very practical, the black version being smart enough to be used as a laid back top.

Bottom line

I personally think this an awesome mid-layer that has almost no drawbacks except its weight and very high price. Merino usually comes with a premium but at twice the price of some similarly specced synthetic midlayers like the The North Face Isotherm Half Zip Top or the Mountain Hardwear Beta Power 1/4 Zip it is a hard sell. Now saying that, do shop around because some online stores have it on sale for around $115 / £70.

[note]The SmartWool PhD HyFi Half Zip was given to us for the purpose of this review. We try our best to not let this affect our views in any ways. Our gear tests are done in real life, during our own outdoor activities.[/note]